HOW BIG OF TB DO YOU NEED FOR YOUR MOTOR? INFO HERE.......

[GoFast.....]

I was doing some research for my 107 and got some reliable info on cfm TB, This is what I like about HTT and the willingness of everyone to share what they know and learn. The TB is sometimes the reason why no matter what you do to your bike you can't get it to run bigger numbers

01-05 TB  184cfm

This Tb is 44mm
but chokes down
to a 38mm behind
the 44mm plate

06-07 TB  217cfm

08- 09 touring models
have 50mm which will
add a little more but
the rest will be like
the 06-07

Screamin  232cfm
eagle

YourStock 246cfm
TB modifed HPI
200.00 PRICE

HPI 51 TB 253cfm
(will out flow a 58
WT TB) 10% off now
The flow changes the bigger
the intake ports are like
1.710 and 1.8

For Most GUYS wanting more over 100hp Sending your TB to HPI for 200.00 is some of the best money you will spend.

http://www.horsepowerinc.net/products/big-bore-throttle-bodies/



HPI 51 AND 07 STOCK TB

[Admiral Akbar]

So where dis you get the data from? What pressure? Max.

[JAFHR]

How can I tell if I have the 50 or other TB on my 08 Ultra. Are you saying that I can send my TB in and have it modified to a larger diameter for $200. How does this differ from buying one of there's?

[ViennaHog]

How can I tell if I have the 50 or other TB on my 08 Ultra. Are you saying that I can send my TB in and have it modified to a larger diameter for $200. How does this differ from buying one of there's?

The 2008 - touring models all have the 50 mm TB, it's a part of the FBW throttle system. All other TC TBs remain unchanged from 2007 AFAIK

[wfolarry]

Sending out a 1 piece [late style] throttle body for any work is a total waste of money. If you need more power put that money in a piggy bank & save up some more & do it right.

[Admiral Akbar]

"after this post Eric should have a 100 of them to do."

Should also ask. Do you get a cut? Max

[Flat Dog]

With all due respect, I've still not seen a group of engineers use flow testing to PROVE that larger or modified venturi throttle bodies will increase the amount and quality of the charge introduced into the air pump on a normally aspirated engine. I am not saying it's not true, but I still haven't seen anyone PROVE beyond a doubt that it is true. Engine building is science, not voodoo.

All I see are dyno sheets showing me nothing-no comparisons, no explanation of HOW these modified TBs are making more HP, etc. Heck-it's a shuck and jive job so far. Prove to me that your product works-don't just tell me it's popular on the internet. So is donkey porn.

If I am wrong, I am more than happy to eat my words and apologize.

[se]

we have seen a 3-5 hp diffrence with a Bored T/b.
the motor was a 95 in, woods tw6g, 10.1 compression, and baisley heads.
a lot of money for little return.
.

[GoFast.....]

we have seen a 3-5 hp diffrence with a Bored T/b.
the motor was a 95 in, woods tw6g, 10.1 compression, and baisley heads.
a lot of money for little return.
.

There is a diffrence between a bored TB and a Modifed TB. The Modifed has porting work done to it

[GoFast.....]

"after this post Eric should have a 100 of them to do."

Should also ask. Do you get a cut? Max

I wish I got a cut. HPI has probably the best afthermarket TB out there and has done extremely well on the dyno with people like Larry, Mike and many others on HTT

[GoFast.....]

With all due respect, I've still not seen a group of engineers use flow testing to PROVE that larger or modified venturi throttle bodies will increase the amount and quality of the charge introduced into the air pump on a normally aspirated engine. I am not saying it's not true, but I still haven't seen anyone PROVE beyond a doubt that it is true. Engine building is science, not voodoo.

All I see are dyno sheets showing me nothing-no comparisons, no explanation of HOW these modified TBs are making more HP, etc. Heck-it's a shuck and jive job so far. Prove to me that your product works-don't just tell me it's popular on the internet. So is donkey porn.

If I am wrong, I am more than happy to eat my words and apologize.

Increaseing TBs has been proven to increase HP on normally aspirated Highperformance Car engines some many times it's not even worth talking about it. Words are hard to eat. Here's some popcorn

[Quick_2s]

Can going to large for your motor hurt you the same as under sizing it? 

[grnrock]

I found my 06 TB Produced 124hp on my 103.I do have a 57mm but sheeeeeeeeeeeeeee run's so fine.mpg is 43@3k
Bill

[tireater]

So HPI can modify my stock 06 T.B. and get me 246 cfm...for $200..right?

[mtnmotorrider]

You guys that don't like the one piece TB on '07's, can you explain what the difference is from the earlier one piece models?  Is it runner design, length, what?  And can an earlier two piece modified by a compedent company be retro fitted to an '07?

[Flat Dog]

Can going to large for your motor hurt you the same as under sizing it? 

Most definitely. A too large TB can cause off the line bogging, tuning nightmares, etc...


Again-no disrespect to the OP or HPI, but as stated-a 2-3HP gain is big stuff at the track, but show me the under redline usable street torque/hp large curve improvement for that 6-700 bucks. I'll eat my popcorn while waiting. I bet I am going to get really fat... That's a lot of money to some people for a tiny little gain.

Yeah, cars have used large CFM double pumper bla bla bla carbs for years, but most of the time it's overkill done by ignorant 'bigger is better' types that haven't really done the math.

[se]

we have seen a 3-5 hp diffrence with a Bored T/b.
the motor was a 95 in, woods tw6g, 10.1 compression, and baisley heads.
a lot of money for little return.
.

There is a diffrence between a bored TB and a Modifed TB. The Modifed has porting work done to it

have not had the opportunity to hear about the modified results but i know if we could send one out i think it is going to Dan Baisley. i beleive he is doing a modified one am i correct as HPI..
i can only speak for what i have saw on the dyno now if you were doing a few other changes such as trying diffrent cams and exhasuts you will most likely see more of an increase then 2-3. 

[se]

Can going to large for your motor hurt you the same as under sizing it? 

Most definitely. A too large TB can cause off the line bogging, tuning nightmares, etc...


Again-no disrespect to the OP or HPI, but as stated-a 2-3HP gain is big stuff at the track, but show me the under redline usable street torque/hp large curve improvement for that 6-700 bucks. I'll eat my popcorn while waiting. I bet I am going to get really fat... That's a lot of money to some people for a tiny little gain.

Yeah, cars have used large CFM double pumper bla bla bla carbs for years, but most of the time it's overkill done by ignorant 'bigger is better' types that haven't really done the math.

with my 120 build we went from a 55mmhpi to a 58/62 hpi. seen a 1-1 gain all the way to the end overlayed the graphs and it was identical just 1hp 1tq higher of a diffrence...
let me get you another bag.......

[Faast Ed]

All I see are dyno sheets showing me nothing-no comparisons,

Here are some comparisons posted just tonight on this board:


http://harleytechtalk.net/htt/index.php?topic=1125.0  (2 into 1 pipe string)

[se]

All I see are dyno sheets showing me nothing-no comparisons,

Here are some comparisons posted just tonight on this board:


http://harleytechtalk.net/htt/index.php?topic=1125.0  (2 into 1 pipe string)

Thanks Ed.

[FLTRI]

But George,
There is a +or- 2hp/tq error in these dynos. So a 1-1 improvement, I think would = 0? 
Bob

[Faast Ed]

I was waiting for someone to say that Bob! 

From one run to the next, you can have that difference without even touching the motor.

[se]

well Bob im sure if i brought it to you you could get better # out of it maybe you could get the +2 out of it for me.
what do you think it was just swapped out and the afr tuned in and then run.
tried that could not get the low speed hesitation tuned out
with that t/b the whole map had to be redone.
but then again Bob you knew that.

oh yes 1 other thing also we tried tuning the motor in the same conditions as the previous day just incase that was your next dig

[skyhook]

I like hpi, got me 11 hp vs stock tb & injectors...latus motors soon to have variable venturi fly by wire, already have cable operated...my friend al is developing dual throat

[Flat Dog]

Thanks skyhook!

[FLTRI]

well Bob im sure if i brought it to you you could get better # out of it maybe you could get the +2 out of it for me. HUH? Where'd that come from?
what do you think it was just swapped out and the afr tuned in and then run.
tried that could not get the low speed hesitation tuned out
with that t/b the whole map had to be redone.
but then again Bob you knew that.

oh yes 1 other thing also we tried tuning the motor in the same conditions as the previous day just incase that was your next dig

George, didn't mean to light you up just made a comment that there was no improvemnt with the larger TB. Sure wasn't trying to indicate it wasn't tuned right, just sometimes mods are made that do not produce the increase(s) expected.
Yes I do know EFI has to be recalibrated for a larger T/B, but every tuner knows that I.

[GoFast.....]

well Bob im sure if i brought it to you you could get better # out of it maybe you could get the +2 out of it for me. HUH? Where'd that come from?
what do you think it was just swapped out and the afr tuned in and then run.
tried that could not get the low speed hesitation tuned out
with that t/b the whole map had to be redone.
but then again Bob you knew that.

oh yes 1 other thing also we tried tuning the motor in the same conditions as the previous day just incase that was your next dig

George, didn't mean to light you up just made a comment that there was no improvemnt with the larger TB. Sure wasn't trying to indicate it wasn't tuned right, just sometimes mods are made that do not produce the increase(s) expected.
Yes I do know EFI has to be recalibrated for a larger T/B, but every tuner knows that I.

One thing about a flow bench is it does not very like a dyno. Come on guys, Matching the cfm of a TB to the cfm of a motor is the basics of engine building.

It does not make any diffrence if it is takeing a Carb Harley to 120hp or a FI . Sonner or later the small hole holds the bike back. The debate should be when it happens, not if

Here is a blast from the past post of Larrys

From: WFOLARRY Sent: 4/5/2008 1:01 PM
in your opinion what is the biggest difference in this combo compared to what you have been building?
anything different in the way the heads were done?

Didn't do anything special with the heads. The biggest hurdle is that stock throttle body IMO. Haven't seen any big #'s with a stocker. The older 2-piece were a lot better. This new style just don't get it. It's OK for what most people want- 100/100 but for the guys that want the big #'s it would be the 1st thing I changed. And that goes for any cam not just this one.


From: WFOLARRY Sent: 4/6/2008 8:40 AM
The 1 piece TB flows about 235 @ 28". The heads on this bike were flowing 276 with a 1" radius fixture on the head. With the stock TB [ported] it pulled 245 & with the HP51 it pulled 276. If you listen to that throttle body when it's on the flowbench it sounds terrible. Probing it you find out why. Looking at the cfm #'s doesn't tell the whole story. This was our biggest problem with this build IMO. But that's what happens when the customer doesn't want to spend the money upfront. After riding it all last year come winter he said 'do whatever it takes'. He's a lot happier now. If a customer doesn't want to change out the TB for a better one I keep the cams on the small side because I haven't seen one yet that made it over 110. They usually come in at 100-106 hp.   

[se]

i apologize for coming off harsh Bob. as far as the tuning goes a lot of guys dont know that.. when i mean change the whole map had to re-tune the bike as it was a new tune. but one thing we did find out that was very imporant was the larger t/b used less fuel in areas then the 55mm did. the stumbling in the low end was a real rich condition. we tried to do a basic swap but the stumbling continueed to get worse the more we tried to adjust the afr. there forth a new tune was needed stumbling stopped bike ran great. and it took approx 2 days to get the 1-1 out of it. 2 hrs one day 2-3 the next. we also determined that the spoke wheels on the deluxe just were not up to par for the bigger build.
also  the quiet baffle came out of the borzilla and the standard baffle went in. we spent approx a week of mornings doing all these tests to try and keep the conditions as close as possible.



ED how much does a good flow bench go for. i see it mentioned a lot.   

[Flat Dog]

Thanks for the info everyone, and I am getting fat on popcorn!

Anyone know who might be working on a FBW TB besides Latus?

Thanks!

-John

[hdtuner23]

Just my opinion here, but it seems only a few are doing the math here. Asking a larger T/B to introduce more air into a motor that does not need or require it, wont make more power.  Simply stating, a t/b is not a super charger. If your heads, cams, combination of parts are done, well a larger t/b wont help.  Remember a build is the sum of parts. JD cycle I'm sure did a great job tuning, but proves again that the heads, cam, displacement, and exhaust were done. Again as GoFast stated, air flow requirements should be matched to achieve great results. Not sitting on a couch eating popcorn, which by the way approximately 1lb. of wt.is equal to 1hp. JD needs to put the stock T/B back on and post his results from that!  By the way, what did the heads flow, and did anyone ever ask what test pressures were used?  WOW!

[GoFast.....]

Just my opinion here, but it seems only a few are doing the math here. Asking a larger T/B to introduce more air into a motor that does not need or require it, wont make more power.  Simply stating, a t/b is not a super charger. If your heads, cams, combination of parts are done, well a larger t/b wont help.  Remember a build is the sum of parts. JD cycle I'm sure did a great job tuning, but proves again that the heads, cam, displacement, and exhaust were done. Again as GoFast stated, air flow requirements should be matched to achieve great results. Not sitting on a couch eating popcorn, which by the way approximately 1lb. of wt.is equal to 1hp. JD needs to put the stock T/B back on and post his results from that!  By the way, what did the heads flow, and did anyone ever ask what test pressures were used?  WOW!

If your heads, cams, combination of parts are done, well a larger won't make more power.

This true and false depending on the combination. If you have serious flowing heads and a bigger cam and the right Exhaust I will lay money on the table that says a bigger TB will help. I was talking to Chris at HPI and he was saying on my 107 that the HPI would deliver 7 to 10 hp over the stock TB. To me that is a lot. IF CAN LIST YOUR COMBINATION WITH THE SIZE OF VALVES AND THE FLOW RATE OF THE HEADS, PLUS THE CAM AND PIPE. There are a lot of guys on HTT that can tell you if a bigger TB will help you includeing myself

[FLTRI]

"approximately 1lb. of wt.is equal to 1hp"
I believe you meant 10lbs per 1hp.

[GoFast.....]

Just my opinion here, but it seems only a few are doing the math here. Asking a larger T/B to introduce more air into a motor that does not need or require it, wont make more power.  Simply stating, a t/b is not a super charger. If your heads, cams, combination of parts are done, well a larger t/b wont help.  Remember a build is the sum of parts. JD cycle I'm sure did a great job tuning, but proves again that the heads, cam, displacement, and exhaust were done. Again as GoFast stated, air flow requirements should be matched to achieve great results. Not sitting on a couch eating popcorn, which by the way approximately 1lb. of wt.is equal to 1hp. JD needs to put the stock T/B back on and post his results from that!  By the way, what did the heads flow, and did anyone ever ask what test pressures were used?  WOW!

If your heads, cams, combination of parts are done, well a larger won't make more power.

This true and false depending on the combination. If you have serious flowing heads and a bigger cam and the right Exhaust I will lay money on the table that says a bigger TB will help. I was talking to Chris at HPI and he was saying on my 107 that the HPI would deliver 7 to 10 hp over the stock TB. To me that is a lot. IF CAN LIST YOUR COMBINATION WITH THE SIZE OF VALVES AND THE FLOW RATE OF THE HEADS, PLUS THE CAM AND PIPE. There are a lot of guys on HTT that can tell you if a bigger TB will help you including myself

[se]

Just my opinion here, but it seems only a few are doing the math here. Asking a larger T/B to introduce more air into a motor that does not need or require it, wont make more power.  Simply stating, a t/b is not a super charger. If your heads, cams, combination of parts are done, well a larger t/b wont help.  Remember a build is the sum of parts. JD cycle I'm sure did a great job tuning, but proves again that the heads, cam, displacement, and exhaust were done. Again as GoFast stated, air flow requirements should be matched to achieve great results. Not sitting on a couch eating popcorn, which by the way approximately 1lb. of wt.is equal to 1hp. JD needs to put the stock T/B back on and post his results from that!  By the way, what did the heads flow, and did anyone ever ask what test pressures were used?  WOW!

like you said it was just your opinion also if you look at the dyno sheets in the dyno forum the conditions are in print on the dyno sheet.. WOW
oh yea why would I put a stock T/B on a fully modified motor? it has been proven time and time again that a larger t/b will help impriove #.
and as far as the math goes we contacted HPI and asked Questions about the motor. their suggestion was to go ahead and try it. the price i paid for the new T/B was very reasonable since we brought a few of them .
the heads ,cam ,pipe and displicment  were not done as you state. once we got the bike running after changing parts , baffle clutch ,rear rim then the bike became easier to tune because the harmonics were better.
once she tuned up we then put the larger t/b on and like i mentioned before had to totally re-tune the bike.

[Faast Ed]

I was talking to Chris at HPI and he was saying on my 107 that the HPI would deliver 7 to 10 hp over the stock TB.

we contacted HPI and asked Questions about the motor. their suggestion was to go ahead and try it.

I've heard more than one person mention that they spoke with HPI and were told that the throttle body would help.  (Likely would, but....)

I ain't doubting their word,......  I also learned long ago to consider the source of any information.  (They just so happen to sell the item they told you you'd benefit from).

I'm pretty sure the local smoke shop would tell me that I need cigarettes,.... LOL  "What size lungs you got?  Oh, you will benefit from these..."   

[se]

I've heard more than one person mention that they spoke with HPI and were told that the throttle body would help.  (Likely would, but....)

I ain't doubting their word,......  I also learned long ago to consider the source of any information.  (They just so happen to sell the item they told you you'd benefit from).

I'm pretty sure the local smoke shop would tell me that I need cigarettes,.... LOL  "What size lungs you got?  Oh, you will benefit from these..."   

absolutely 100%correct. did we need it the answer is NO.. did i want it YES.

[roadglide65]

This maybe a dumb question???

But where dose the intake runner size come into play on this IE 1.6, 1.7, 1.8 as far as CI or build size?

[Billy]

Not sitting on a couch eating popcorn, which by the way approximately 1lb. of wt.is equal to 1hp.

It might be cheaper (for me) going to Jenny Craig and losing 50 lbs to make my bike faster.

[kevmac]

layoff that jack black Billy

[kevmac]

You'll drop that weight in no time

[maineultraclassic]

I've always debated going with a larger TB on my build, like a HPI 48mm or a Hillside bored 46.5 or Dakota Kid bored 48mm.
Almost all the people I spoke with and asked this question to told me not to with my build. I like torque over hp........because without torque there is no hp.

95", 10-1CR, Big Boyz heads with 1.9" intakes, Woods TW-6G cams, Doherty PowerPacc air cleaner, Fatcat 2-1 w/quiet baffle. This is with the stock '05 44mm TB.

So I've always listened to them and kept the stock TB..........and I'm happy with the results and power.

So what's the general thought..........were they right?

Steve

[ameagle13]

Bike is 07 FLHX, MILEAGE 4768, SE HEAVY BREATHER, STOCK THROTTLE BODY W/ SE 4.89 GMS/SEC INJECTORS, 103CI, SE 260 CAMS, COMETIC .030 HEAD GASKET, HTCC PORTED HEADS, HTCC HI COMP PISTONS, RINEHART TRU-DUALS, 6-SPEED, SERT
CHECK B4 THROTTLE ADDITION
5TH GEAR

We knew there was power left on the table with this build and we also knew that the stock throttle body was probably the culprit.  Installed an HPI 55mm throttle body with the stock components and ran it again.  There was no tuning involved b/c we were going to change the exhaust as well to a D&D FatCat(gained 4hp with that addition after tuning).

[attachment removed after 60 days by system]

[ejk_dyna]

nice  10hp increase with no tuning.  and no tq decrease anywhere with the bigger tb.

[GoFast.....]

Bike is 07 FLHX, MILEAGE 4768, SE HEAVY BREATHER, STOCK THROTTLE BODY W/ SE 4.89 GMS/SEC INJECTORS, 103CI, SE 260 CAMS, COMETIC .030 HEAD GASKET, HTCC PORTED HEADS, HTCC HI COMP PISTONS, RINEHART TRU-DUALS, 6-SPEED, SERT
CHECK B4 THROTTLE ADDITION
5TH GEAR

We knew there was power left on the table with this build and we also knew that the stock throttle body was probably the culprit.  Installed an HPI 55mm throttle body with the stock components and ran it again.  There was no tuning involved b/c we were going to change the exhaust as well to a D&D FatCat(gained 4hp with that addition after tuning).

Thanks for backing up what most of us know, The more your build will flow cfm the more the stock TB becomes a restriction. The HPI TB are 10% now and NO I do not get a cut but I am going to recommend it the next time I call. The next best thing could be the your Modifed Stock TB but we do not have HTT PROVEN results.

[GoFast.....]

I've always debated going with a larger TB on my build, like a HPI 48mm or a Hillside bored 46.5 or Dakota Kid bored 48mm.
Almost all the people I spoke with and asked this question to told me not to with my build. I like torque over hp........because without torque there is no hp.

95", 10-1CR, Big Boyz heads with 1.9" intakes, Woods TW-6G cams, Doherty PowerPacc air cleaner, Fatcat 2-1 w/quiet baffle. This is with the stock '05 44mm TB.

So I've always listened to them and kept the stock TB..........and I'm happy with the results and power.

So what's the general thought..........were they right?

Steve

One thing EVER GUY NEEDS TO GET WITH HIS HEADS ARE THE FLOW NUMBERS. All 1.9 ported heads are not equal in flow numbers. 44MM IS Probably on the small side but for 200 bucks you can send it in to hpi. We need someone here to verify that a modified

[tireater]

OK...I am going to buy a HP inc T.B. for my 06 103" St Bob...
WT26, SE forged Pistons, 04 Hals speed shop pro st heads with grooves, Ness BS2...10.4CR...ThunderTrapp ex.
Should I get the 51mm or the 55mm...? And what runner size...Thanks

[Showdog75]

Runner size should depend on your heads . If you ever plan on going any bigger than 103 I'd go for the 55mm . I'd probably go with the 55 anyway. You need to get a GOOD tuner to tune that puppy .

[GoFast.....]

OK...I am going to buy a HP inc T.B. for my 06 103" St Bob...
WT26, SE forged Pistons, 04 Hals speed shop pro st heads with grooves, Ness BS2...10.4CR...ThunderTrapp ex.
Should I get the 51mm or the 55mm...? And what runner size...Thanks

Tireeater I am going to say something right here about the WT 26 BUILD. A lot of people do ok with this build who throw parts together and then there are those who know how to make the most of the WT 26 Mike and showdog really know how and have built several of them and has got impressive results. I want you to be happy with this build so the heads need to be done right and the compression has to also be done right,
If you want me to help I need the cc of the heads, valve sizes of the heads and the flow bench on them first.I would call Eric on the size of the TB.It's his Day Job

[Bagger]

Check out my dyno in dyno section.  Dyno shows 95" w/stock 44mm TB and 98" w/HPI 48MM TB.  No gains on the dyno or on touring performance.

http://harleytechtalk.net/htt/index.php?topic=942.msg7490#msg7490

[Admiral Akbar]

What's you point? You've got a low mechanical compression and wimpy cam.. Not sure you'd see any difference on the bore.. Max

[Faast Ed]

Kind of fits the words Ed E said over on the groove string (whether they help or not):

"Depends on the build".


I too was going back/forth on whether to get a HPI 51 for my build, but I think I am in the same boat as Bagger with not enough cam to benefit from a bigger TB. So I think I shall buy lots of beer instead.

[Don D]

Ed
It would help a little as did the pipe but just at the top and a through retune would be needed. I agree likely not worth it.

[FLTRI]

So, can we all agree that simply bolting a bigger TB onto a build will NOT always produce expected results?

Can we all also agree that simply increasing the ci doesn't necessarily warrant a larger TB?

If so, we can then agree that the entire engine build is what dictates TB size, not individual mods, ie: ci, cams, etc.

If we can all agree with those statements then we know bigger is not always better, no matter who makes it or how much it costs, or how shiney it is.

Just my deduction from this thread,
Bob

[skyhook]

bob I mostly agree...however I've come to believe the one piece t/b's are crap...I would change to hpi 51mm even if I was running a 96" with andrews 21 cams and mild headwork...why?...I just think the area behind the throttle blade is so restrictive that the hpi would significantly improve throttle response...this is something that may not show up on a dyno chart, but is worth doing nonetheless if the customer has the cheese!

[Faast Ed]

...this is something that may not show up on a dyno chart,

I sure wouldn't want to pay for something that won't show on the dyno chart (not a big ticket item).
However, I can see how it would make one feel better about their build (eliminating a known bottleneck) and also it could be helpful if some future mods can benefit from it.

So, can we all agree that simply bolting a bigger TB onto a build will NOT always produce expected results?

I surely agree. (but I still get the urge to consider a bigger TB). LOL   I doubt that it will happen while running this particular cam.
besides, my tuner is likely sick of me taking up all his dyno space!  LOL

[FLTRI]

"however I've come to believe the one piece t/b's are crap...I would change to hpi 51mm even if I was running a 96" with andrews 21 cams and mild headwork...why?...I just think the area behind the throttle blade is so restrictive that the hpi would significantly improve throttle response..."

AKAIK, the smaller the TB the more throttle response.
I have had my 117ci with a stock 2003 TB. Guess what? The throttle response was incredible, however the top end HP was down about 15. When I put a 58mm TB on it the power above 4000 went up considerably but the throttle response (SOP) went down.

I'm going to a 51mm TB because for my touring bike build (big ci, low compression) because I think it will outperfom the 58mm everywhere except where I do not ride (>5500)

So, IMO, the smallest TB that will feed the engine what it wants will outperform a TB that is bigger than necessary.

It's kinda the same as with a carb but the fuel is precisely metered and dictated unlike a velocity sensitive carb.

We discount velocity is still as important with EFI as with a carb for VE quality (cylinder fill)

As always, JMHO, Bob

[GoFast.....]

What's you point? You've got a low mechanical compression and wimpy cam.. Not sure you'd see any difference on the bore.. Max

Let me say it a little nicer than MAX  The small cam and low compression do not have a strong enough signal or is not calling for more air than what a stock TB has. A 31 closings is to small of cam to take advantage and it also is to small of a cam to take advantage of the larger cubic inches. If you keep it like this you mize as well sell the hpi to someone that needs it

[Lovetoride007]

I also am putting together a 107Ci on a 2004 bagger, heads are ported flowing approx 155 cfm on intake ,going with HQ575 cams, compression is 9.9 to 1 , will this set up benefit enough to warrent spending the money for a bigger TB, and how big

[skyhook]

another thing about dyno charts they are at wot...how much time do you spend there?...how much does wot power have to do with normal riding?...my chart with hpi 55 shows I lost a lot of tq at wot, but it is just as strong at 2, 5, and 10% as it was with the stock 50...and the larger throttle blade improves throttle response significantly...so I am not convinced that a smaller t/b with a bad intake(the stocker) is going to work better than a work of art hpi AT ANY throttle position

edit: I'm talking about one piece t/b's being crap...and I believe velocity is controlled by the port and valve, not the tb, especially at part throttle

really not trying to pick a fight with you sir, I do respect your considerable experience with these motors

[GoFast.....]

another thing about dyno charts they are at wot...how much time do you spend there?...how much does wot power have to do with normal riding?...my chart with hpi 55 shows I lost a lot of tq at wot, but it is just as strong at 2, 5, and 10% as it was with the stock 50...and the larger throttle blade improves throttle response significantly...so I am not convinced that a smaller t/b with a bad intake(the stocker) is going to work better than a work of art hpi AT ANY throttle position

edit: I'm talking about one piece t/b's being crap...and I believe velocity is controlled by the port and valve, not the tb, especially at part throttle

really not trying to pick a fight with you sir, I do respect your considerable experience with these motors

I think we also have to remember that the stock head is going to restrict flow also

[skyhook]

yes, definitely depends on the build...I also believe in running baby cams in '06 and later motors unless you upgrade EVERYTHING

but I still believe throttle response will improve with a totally stock, correctly tuned motor with a 48 or 51 hpi

I'm not selling anything here, do not work for hpi, just voicing my opinion

[Bagger]

GoFast, IMHO a HPI 48mm - 51mm versus stock TB IMHO would complement your build and provide quick and smooth throttle response.  It would not be over throttle bodying your build.  The HPI TB is a quality piece of workmanship.  To some it may not be cost effective, but for me, it was money I didn't mind spending. 

Well, I agree with what FLTRI said about velocity and cylinder fill relating to throttle response - don't want to over TB a build for the sake of a few HPs in an rpm range not ridden in.   

In my bagger build, the throttle response is immediate and smooth, no high revving to get it moving.  This bagger with it's wimpy cam (9.0:1 corrected CR), immediate acceleration and the 1700 to 3000 rpm TQ is well suited for an annual ride from Florida to Maine and on into Canada.  It's ideal for riding up through the Smokey and Pocono Mountains, pulling out of corners on winding back country roads, accelerating past semi-truck on the interstate and riding through the streets of Manhattan.   And after I put 100,000 miles on the bike, I may take the engine to 106" or 107", and the 48mm TB will be ideal match IMHO.

[GoFast.....]

yes, definitely depends on the build...I also believe in running baby cams in '06 and later motors unless you upgrade EVERYTHING

but I still believe throttle response will improve with a totally stock, correctly tuned motor with a 48 or 51 hpi

I'm not selling anything here, do not work for hpi, just voicing my opinion

I was talking to Eric at HPI and he reminded me of something I had forgot about earlier than 06 stock TBs.The throddle plate is 44mm but they are really 38 mm because they are two pieces. The intake manifold behind the the throttle plate norrows to 38 mm restricting the flow. To see this all you have to do is take a flash light and open up the throddle and as you look down the TB you will see it choke down behind the Throddle plate. Someone shold be able to post a picture of it here on HTT.These TBs really need improved as the cfm increases with High perfomance upgrades. Trying to make serious horsepower with these is really like beating a dead.......

[Bagger]

To beat  just a bit more, here's some additional V-Twin Forum comments made by a respected engineer.  Although comments primarily relate to a 95", the same philosophy can be applied to larger cubic inch builds.  Increased velocity seems to be objective.

05-24-2004, 02:56 PM 
GRock 
Premium Member   Join Date: Apr 2004
Location: connecticut
Posts: 1,897

http://www.v-twinforum.com/forums/showthread.php?t=37459&highlight=48mm
clive,
You are probably ok, but I've tuned a few EFI's in my time and we are finding that stock delphi is marginal for 95". Your cam is not too radical, but as long as you are headed to the dyno I will give you a hint. Record MAP readings on Race Tuner while doing 4th gear roll on. If graph starts to get jumpy in higher RPM range (4700 RPM and up), motor needs more air. For 95" you probably only need to have stock throttle body bored out. It's cheaper than whole new unit and air box. However, if you are going to continue the quest for more power by going larger cubes, you will absolutely require more air. Zeus, with all due respect anything above 100" benefits from larger than stock. My 107" was limited in HP with bored delphi. Went to dual runner and just re-tuned and gained 6 HP and about 8 lbs TQ. And got smoooooother running in the lower ranges. By the way I have a couple BC Gerolamy re-worked Dephi units with manifolds that I'll sell cheap if you find you need one.

I've been researching V-Twin, HP Inc and others for opinions on upgrading TB.  HP Inc recommended their 48mm for the 98" kit.  I'll be running this to the ground to learn pros/cons, especially to low end TQ.

http://www.v-twinforum.com/forums/showthread.php?t=65094&highlight=48mm

11-04-2005, 01:03 AM 
GRock 
Premium Member   Join Date: Apr 2004
Location: connecticut
Posts: 1,897


Just to let you guys and the rest that are considering EFI builds know.....

When you go to nicely ported heads like Baisley and keep the stock TB, you are definitely holding back the flow.

MAP almost always will start to drop from anywhere from 4100 to 4700 on a decent 95 and higher build with the Delphi. BUT.... the difference in HP is maybe 3 to 4 HP with a cam like the 37. And some of that may be caused by front to rear fuel reversion at high R's. So not a big deal on the TB size. Remember that you aren't hanging around in the 4000 to 5000 rpm range for very long anyway. The most that you can bore out of the stock Delphi is about 3mm MAX, and although that will move your MAP drop up a few hundred R's, it doesn't completely solve the issue you are having. Again, I'm not calling it a problem because it really isn't on a cam like the 37. This is for up to 2005 models.

The 06's have their own problems in this arena, but some of those are influenced more by the smaller injector size that simply will not support high HP engines because of the limited pulse width. This, COMBINED with the TB bore, WILL cause problems on 06's that are trying to make big power.

Anyway, don't everyone go crazy buying big TB's, because in most cases you will never feel the difference. Really a nice alternative is to send them out to a guy like Dakota Kid who will not only increase the bore but also increase intake velocity due to his re-work. And that, my friends, is the real key!

As for the quote from Daytona Twintec on the inadequecy of the stock TB, while Chris Schroeder is a pretty sharp guy, his numbers on the limitations of the Delphi show that it is inadequate to maintain MAP gain. But it really does not affect streetability of most 95" builds. And his limitation on the HP number is really not a limitation at all. (BTW, you can get more that 105). MOST 95" street builds are not making too much more than 105 HP anyway. And TQ is always on the way down by the time that MAP drop occurs anyway. So what are you losing? Not much.
Take that quote with a grain of salt!

FYI

All the best

03-23-2005, 08:32 PM 
GRock 
Premium Member   Join Date: Apr 2004
Location: connecticut
Posts: 1,897 

Quote:
Originally Posted by SYCLONE
Do you think with the numbers he's already making now with his build that a larger T-B will make improvements worth the cost. Seems pretty stout right now. You have fooled with these as much as anybody...where and what kinds of gains do you think he'll see. Especially interested in what you have found to be the advantages/disadvantages of dual vs siamese manifolds when you have run them on the same motor. I would guess that a properly sized dual runner would be easier to tune, make more torque sooner, and be less prone to reversion with big cams running lots of overlap. Grock..time to spill the beans !!

Unfortunately, with the price of these things it is rarely worth the cost for this mod on a 95". Your gains are only going to be in the higher rpm ranges anyway, as the MAP pressures begin to go a little squirrely when you hit aroung 5200 - 5400 RPM. You will get a few more ponies out of a build like this, but, like SYCLONE says you are running real nice for a 95 and nothing will be noticed in the normal riding ranges with the TB mod.. If mores cubes and bigger HP numbers are in the future, then look into it, otherwise it is a want item and not necessarily a need item.

SYCLONE,
You make a good point, but I was simply giving the poster where to's on getting a larger throttle body. I would think that the money should stay in his pocket OR, if he likes to spend, have his TB bored for around $325 at a couple of different shops that I know of. But the 48mm bore is really nominal for the build he has and will not hold up for bigger mods later. As for your assessment of dual runner vs. siamese, yes, I do prefer the dual runner design for larger motors and cams with long duration and high overlap where they definitely are easier to tune and eliminate front to rear fuel reversion. Seems to give smoother running and when larger injectors are used, low speed operation and idle are easier to control. In short, for all you guys and gals that have done the 95's, it is rarely worth the cost of a new TB to justify the cost unless the 95 build is just temporary medicine for the performance fever.

[Bagger]

FWIW, J.E.T comments regarding velocity.  The J.E.T website shows their dyno testing results.


http://www.cyclespot.com/forums/showthread.php?t=14729

Modified Throttle Body??? Thoughts?

--------------------------------------------------------------------------------

I was checking this out on the J.E.T. website and was thinking about this as a mod but wanted to hear from some of the wrench experts...Below is their performance claims. The 48mm is $170.00 and the 51mm is $366.00 Thoughts please...

J.E.T Website:  http://www.johnsonenginetechnology.com/JETPAGES/parts/twin-cam-throttle-body.html

Our goal when we started our project was to offer our customer’s a high horsepower throttle body option for a lower cost than what is currently available. Right now, big throttle bodies are available from Screamin’ Eagle and other aftermarket manufacturers at costs between $400 and $800. They all produce good results, but the total cost of installation and tuning can be over $1000. For just a small increase in performance, this can seem a little expensive to many people. Instead of having to purchase an expensive new unit, we set out to see what we could accomplish by some simple inexpensive modifications to the stock unit.

All ’05 and later Twin Cams (except for ’08 FLH’s) come with a one piece 46 mm throttle body. Upon testing we found that this 46mm unit was limiting customers to about 92-98 HP depending on displacement and the level of performance work. We found the overall design of the part to be a little lacking (it was clearly designed without performance in mind). The port runner increases in diameter from 1.900” to over 2” after the butterfly and still gets larger in area until the port exit at the cylinder head which is 1.640.” Any intake manifold that is designed to increase engine performance has port runners that are smaller then the butterfly, which also has a constant taper to the cylinder head. This is done so that the air in the throttle-body is constantly increasing in speed (this reduces reversion and increased throttle response, it also helps prevent detonation by keeping the fuel in suspension (low velocity and reversion cause fuel to fall out of suspension which increases the likely hood of detonation).

We flow tested the stock throttle body and found out that it flowed 219 CFM at 28.” We then bored it out to 48mm (.090” bigger than stock). The manifold was flow tested with just the bigger 48mm butterfly and we saw an increase of 13 CFM (232 @28”) We then did a little bit of clean up porting and re-flow tested the throttle body with results showing an increase of 22 CFM (241 CFM @ 28”). After flowing the throttle body we installed the unit on a 103 cu” TC with a mild camshaft and 9.8:1 compression ratio (baseline power of 92 HP and 104 ft lbs torque). Upon installation of the 48mm High-Flow throttle body and proper tuning; the HP increased to 96 HP and the torque increased to 106 ft lbs. SEE DYNO

Seeing as the 48mm worked so well, we thought we would push it a little further and try going to 51mm. After re-boring the throttle-body to 51mm (an increase of .196” over stock), we flowed the throttle body and that’s when the bad news started. The 51mm throttle body only flowed 243 CFM @28” an increase of only 2 CFM over the 48mm unit. Seeing as the flow bench is not always a tell-all in performance, we then installed the part on the same 103 cu” TC as before and proceeded to test and tune the 51mm throttle body. The results were not good; the HP and Torque both went down about 3-4 units in the low and midrange RPMs, but the power above 4750 RPM increased by about 4. SEE DYNO

All in all I would say that the 51mm ported stock throttle body was a failure, because not many people spend a lot of time riding above 4750 RPM, but we were determined to make the 51mm throttle-body work. We thought about what we could do to increase the velocity behind the butterfly. Increasing the velocity and the CFM would increase the power everywhere and make better use of the big butterfly. The port runners were then cleaned up and some very high-tech epoxy was used of fill the ports (to replicate the port runners of our J.E.T. intake manifolds). After the manifold was epoxied and ported, we tested it on the flow bench and it flowed a lot more with the epoxy, 257 CFM @28”. Now we were faced with a manifold that was about 15% smaller, had the proper taper that an intake should have, and it flowed 14 more CFM (38 more CFM than stock!!!!) This could only mean that the port velocity was much higher in the manifold with the epoxy. So we took the 51mm High-Velocity throttle-body to the dyno.

Unfortunately, we were unable to retest the epoxied 51mm High-Velocity throttle body on the same 103 cu” TC, so we took advantage of a very mild 106 cu” TC with a very good baseline on it and a stock throttle body. The 51mm epoxy unit was installed and properly tuned in. This is where the results turned for the better… way better. SEE DYNO

The HP went from 100 HP to 107 HP and the torque went form 110 ftlbs to 115 ftlbs of torque. We also noticed the power increases were produced throughout the entire RPM range and not just in the higher RPM areas. These results were very encouraging find and could only mean one thing; we accomplish our original goal.
As a result, Johnson Engine Technology, Inc. can now offer a service that will take the stock throttle body of a potential customer and modify it for optimum performance without the high cost of the aftermarket part.
__________________
Life Blows... Enjoy the Breeze

Semper Fi

[GoFast.....]

FWIW, J.E.T comments regarding velocity.  The J.E.T website shows their dyno testing results.


http://www.cyclespot.com/forums/showthread.php?t=14729

Modified Throttle Body??? Thoughts?

--------------------------------------------------------------------------------

I was checking this out on the J.E.T. website and was thinking about this as a mod but wanted to hear from some of the wrench experts...Below is their performance claims. The 48mm is $170.00 and the 51mm is $366.00 Thoughts please...

J.E.T Website:  http://www.johnsonenginetechnology.com/JETPAGES/parts/twin-cam-throttle-body.html

Our goal when we started our project was to offer our customer’s a high horsepower throttle body option for a lower cost than what is currently available. Right now, big throttle bodies are available from Screamin’ Eagle and other aftermarket manufacturers at costs between $400 and $800. They all produce good results, but the total cost of installation and tuning can be over $1000. For just a small increase in performance, this can seem a little expensive to many people. Instead of having to purchase an expensive new unit, we set out to see what we could accomplish by some simple inexpensive modifications to the stock unit.

All ’05 and later Twin Cams (except for ’08 FLH’s) come with a one piece 46 mm throttle body. Upon testing we found that this 46mm unit was limiting customers to about 92-98 HP depending on displacement and the level of performance work. We found the overall design of the part to be a little lacking (it was clearly designed without performance in mind). The port runner increases in diameter from 1.900” to over 2” after the butterfly and still gets larger in area until the port exit at the cylinder head which is 1.640.” Any intake manifold that is designed to increase engine performance has port runners that are smaller then the butterfly, which also has a constant taper to the cylinder head. This is done so that the air in the throttle-body is constantly increasing in speed (this reduces reversion and increased throttle response, it also helps prevent detonation by keeping the fuel in suspension (low velocity and reversion cause fuel to fall out of suspension which increases the likely hood of detonation).

We flow tested the stock throttle body and found out that it flowed 219 CFM at 28.” We then bored it out to 48mm (.090” bigger than stock). The manifold was flow tested with just the bigger 48mm butterfly and we saw an increase of 13 CFM (232 @28”) We then did a little bit of clean up porting and re-flow tested the throttle body with results showing an increase of 22 CFM (241 CFM @ 28”). After flowing the throttle body we installed the unit on a 103 cu” TC with a mild camshaft and 9.8:1 compression ratio (baseline power of 92 HP and 104 ft lbs torque). Upon installation of the 48mm High-Flow throttle body and proper tuning; the HP increased to 96 HP and the torque increased to 106 ft lbs. SEE DYNO

Seeing as the 48mm worked so well, we thought we would push it a little further and try going to 51mm. After re-boring the throttle-body to 51mm (an increase of .196” over stock), we flowed the throttle body and that’s when the bad news started. The 51mm throttle body only flowed 243 CFM @28” an increase of only 2 CFM over the 48mm unit. Seeing as the flow bench is not always a tell-all in performance, we then installed the part on the same 103 cu” TC as before and proceeded to test and tune the 51mm throttle body. The results were not good; the HP and Torque both went down about 3-4 units in the low and midrange RPMs, but the power above 4750 RPM increased by about 4. SEE DYNO

All in all I would say that the 51mm ported stock throttle body was a failure, because not many people spend a lot of time riding above 4750 RPM, but we were determined to make the 51mm throttle-body work. We thought about what we could do to increase the velocity behind the butterfly. Increasing the velocity and the CFM would increase the power everywhere and make better use of the big butterfly. The port runners were then cleaned up and some very high-tech epoxy was used of fill the ports (to replicate the port runners of our J.E.T. intake manifolds). After the manifold was epoxied and ported, we tested it on the flow bench and it flowed a lot more with the epoxy, 257 CFM @28”. Now we were faced with a manifold that was about 15% smaller, had the proper taper that an intake should have, and it flowed 14 more CFM (38 more CFM than stock!!!!) This could only mean that the port velocity was much higher in the manifold with the epoxy. So we took the 51mm High-Velocity throttle-body to the dyno.

Unfortunately, we were unable to retest the epoxied 51mm High-Velocity throttle body on the same 103 cu” TC, so we took advantage of a very mild 106 cu” TC with a very good baseline on it and a stock throttle body. The 51mm epoxy unit was installed and properly tuned in. This is where the results turned for the better… way better. SEE DYNO

The HP went from 100 HP to 107 HP and the torque went form 110 ftlbs to 115 ftlbs of torque. We also noticed the power increases were produced throughout the entire RPM range and not just in the higher RPM areas. These results were very encouraging find and could only mean one thing; we accomplish our original goal.
As a result, Johnson Engine Technology, Inc. can now offer a service that will take the stock throttle body of a potential customer and modify it for optimum performance without the high cost of the aftermarket part.
__________________
Life Blows... Enjoy the Breeze

Semper Fi

This confirms what Eric AT HPI said to me about the turn into the port. It is to abrupt and by adding something to smooth it out it flows better.  My only question would be I would hate for that expoxy to come lose and suck it down the engine.

[FLTRI]

"After the manifold was epoxied and ported, we tested it on the flow bench and it flowed a lot more with the epoxy, 257 CFM @28”. Now we were faced with a manifold that was about 15% smaller, had the proper taper that an intake should have, and it flowed 14 more CFM (38 more CFM than stock!!!!) This could only mean that the port velocity was much higher in the manifold with the epoxy."

"The HP went from 100 HP to 107 HP and the torque went form 110 ftlbs to 115 ftlbs of torque. We also noticed the power increases were produced throughout the entire RPM range and not just in the higher RPM areas."

So, once again it's not the size but how you use it, and bigger is not always better.

[Bagger]

So, once again it's not the size but how you use it, and bigger is not always better.

FLTRI, you may have read these articles before, if not here's Robert Johnson's (JET) take on port size and velocity.

http://cycledoctor.com/Articles/JET.htm
http://cycledoctor.com/Articles/head2head.htm

[Don D]

"If so, we can then agree that the entire engine build is what dictates TB size, not individual mods, ie: ci, cams, etc."

You could substitute the word "pipe" or "cam" or whatever part of the build for the word "TB". I see too much of this and not viewing the motor as an engineered system rather than picks off a menu.

Regarding the JET philosophy, it did have merit in the EVO days and reducing the ports did help mild builds with 80" motors. Today if we want to have a torque monster that stops at 5K it will work too on a 95" motor. If it were mine though I would prefer a little more top end and sacrafice a small amount down low. Cams and cam timing and exhaust can be coordinated to fine tune these things without pulling the heads or just Blueprinting them.

Good thread!

Agree with most all said here.

[FLTRI]

"FLTRI, you may have read these articles before, if not here's Robert Johnson's (JET) take on port size and velocity."

Interesting to note how few listen to, and take the advice from, those who do not subscibe to the bigger is better misconception.
Bob

[GoFast.....]

"FLTRI, you may have read these articles before, if not here's Robert Johnson's (JET) take on port size and velocity."

Interesting to note how few listen to, and take the advice from, those who do not subscibe to the bigger is better misconception.
Bob

Bob, It because it is a half truth. Bigger is always better if you have the combination to flow it without losing velocity

[FLTRI]

"without losing velocity"
There enlies the key to TB sizing rather than just assuming because it's bigger it wants/needs more air.
I mean there a folks with $700+ HPI TB, 95ci with se203, tw6, tw26, etc, and stock heads, even when the dyno confirms no power improvement.

[Faast Ed]

Bob, It because it is a half truth. Bigger is always better if you have the combination to flow it without losing velocity

Not every build involves "the combination to flow it without losing velocity".  Hello? Very many builds do not fit that catagory.

Soooooo.....,   "Bigger is NOT always better".  Whole truth, not half truth.

[FLTRI]

"I never put a Tb that is too big for the combination of build no matter if it is a small block chevy or a Harley"

How can you be sure? EFI is not quite the same as a carb when it comes to determining what is too big.

It is much easier to determine if a carb is too big because it won't feed fuel properly.

EFI systems dictate the fuel quantity and timing so it becomes much more subjective as to what is too big for a TB.

This is why, for the street, I like to error on the side of smaller rather than larger. This attitude assures excellent throttle response and low rpm smoothness.
If it was a race bike my attitude would be much different, as the upper rpms (>4000) are the most important so bigger could be better.

I guess if I were selling TBs I would always reccomend bigger than what the customer currently had mainly because the engine will run just fine with a bigger-than-necessary TB, maybe just down a bit in the response and low rpm manners.
A carb salesman could not get away with selling bigger than necessary because the engine would run like crap.
JMHO, Bob

[fuzznut5197]

This confirms what Eric AT HPI said to me about the turn into the port. It is to abrupt and by adding something to smooth it out it flows better.  My only question would be I would hate for that expoxy to come lose and suck it down the engine.

While JET is mentioned, has anyone ever seen this:

http://www.veta.com.au/pages/applications/lotus%5B1%5D.pdf

I was surfing around looking for why you would put golf ball dimples in the intake (from VTF), and stumbled across it. Looks like a JET or R&R port. But my pea brain still doesn't understand it. 

[Faast Ed]

ED, If you are going to Quote me Quote the whole sentance. Plus I never put a Tb that is to big for the combination of build no matter if it is a small block chevy or a Harley. There are two kind of engine builders. Builders and Master Builders. I'm a part of the second group.

Okay.("If you are going to Quote me Quote the whole sentence.")

I never put a Tb that is to big for the combination of build no matter if it is a small block chevy or a Harley.

This string is not about you or your building tastes. It is about TB size in general as it relates to all of our builds.
Very informative string, to say the least!

There are two kind of engine builders. Builders and Master Builders. I'm a part of the second group.

If saying that makes you feel better so be it. Your posts speak for themselves. (gotta love that ego)
It takes a real lot to be a master builder.  (I ain't claimin' to be one - too much respect for those who fit that discription).

[GoFast.....]

This confirms what Eric AT HPI said to me about the turn into the port. It is to abrupt and by adding something to smooth it out it flows better.  My only question would be I would hate for that expoxy to come lose and suck it down the engine.

While JET is mentioned, has anyone ever seen this:

http://www.veta.com.au/pages/applications/lotus%5B1%5D.pdf

I was surfing around looking for why you would put golf ball dimples in the intake (from VTF), and stumbled across it. Looks like a JET or R&R port. But my pea brain still doesn't understand it. 

I think it has to do with devoloping a perfect fuel/air mixture, In the old days we used to polish the intake and leave the exhaust rough because we thought it would flow faster. Then we all the testing equipment came out it proved to be the opposite, Rough on the intake and polished on the exhaust. Who would have thought it to be true years ago

[sean fxd]

<<There are two kind of engine builders. Builders and Master Builders. I'm a part of the second group.>>

GoFast -

So you are a master builder?   

What is your shops name and where are you located?  Do you have customer dyno's of the various builds you have done?

Sean

[FLTRI]

 

[Killer]

Lol....That's funny.

[GoFast.....]

<<There are two kind of engine builders. Builders and Master Builders. I'm a part of the second group.>>

GoFast -

So you are a master builder?   

What is your shops name and where are you located?  Do you have customer dyno's of the various builds you have done?

My family owned and operated a Harley Shop for years in Scottsbluff Nebraska, It was called Bluffs Cycle Center. Ever tried to sale a Shovelhead Harley. m50 125, 250 junk sprint built by AMF bowling equipment in the winter to to pay the bills. We raced a Harley Sporster out of our shop in the 70s and 80s . I'll post a picture of the first chooper my brother and I built in our shop. He was 18 and I was 16. 38 years ago, We thought it was pretty "masterful" even at that age.


Now Lets get back to TBs, because I am still all about learning and growing

[nightmare7306]

Ok, how about this build. 95", SE251 cams, 10.25 comp, ported heads but staying with 1.80 intake valve. Bigger tb worth it or is the intake valve the bottleneck?

[GoFast.....]

Ok, how about this build. 95", SE251 cams, 10.25 comp, ported heads but staying with 1.80 intake valve. Bigger tb worth it or is the intake valve the bottleneck?

Nightmare, just off the cuff I would say its the heads, From now on I would get a flow sheet with the ported heads because not all ported heads are equal. Plus There is also no way to know the true compression of your bike without knowing what was done to the heads

[Faast Ed]

So delete your "Hello?" comment that pisses me off

You you delete your "half truth" comment, that pisses me off.

You see Gofast, it works both ways.  Hello?  Bwahahahaha!

[mayor]

this is a good thread with plenty of good information.  Rather than just saying "post your build details and an expert will tell you what to do", why not tell us how we too can become experts.  I think the general thing this thread lacks is a way for the novice engine builder to tie together this information on how it it may affect them and their build. There's been plenty of talk about head flow and TB flow, but no posted examples of what a stock '06 and up head flows at various lifts or what typical flow rates for mild porting and full performance porting. I used the '06 and up heads as an example since most are looking for 96" and up upgrades, but the same information should be listed for the older castings.  Furthermore, the traffic cop in all that air flowing equation (cams), really hasn't been touched on that much either. 

I also think that it should be stressed more that flow rates vary depending on the test pressure method (as Max insinuated in post #2).  A novice may look at his head flowing a maximum of 150cfm (at 10") and be upset that his buddy's heads flowed 235cfm (at 28").  Without putting things into context the information can be confusing. 

jmho,
mayor

[mtnmotorrider]

There are two kinds of baters...   

[HV]

Gentelmen ( and I use that term loosley ) keep it to the point of the original question... and not who had the bigger or better Sand box etc!!  or we will start using the Ban Switch.. ..and this goes for ANY ONE  

[Faast Ed]

You can't dig on Don anymore so you have to find someone else.

I ain't "digging" on nobody Gofast. I was just responding sarcastically to your "cocky" comments.
This is just a message board, you shouldn't get so worked up about it.

Relaaaaax!   LOL   Not everybody builds bikes that require large throttle bodies. Accept that, okay?
The proof is in the posts on this thread, that voice the experiences of many.
It's like buying a product online: The reviews of many tell the story. (Not the reviews of one person).



HV, Please accept my apology.  Had to set the record straight.  If you need to ban or delete, I will understand.

[HV]

Some debates and chest thumping have been carried over here from the old HTT ...and threads will start to just go away ......everyone is entitled to their opinion Mr Fast ... even if it may not agree with yours... live with it... move on

[kevmac]

There are two kinds of baters...   

master and jail?

[se]

  i think you are correct altho i am no expert by any means like i said i can tell you what i have done . i have noticed that there is a lot ofknowledge on this forum and that the experienced builders try to point people in the direction that are proven and true products. the results may vary but i can speak for us is we have made a lot of learning experiences . i have did things to my motor and have taken suggestions from certin so called half a$$ed mail order builders that i should not of with bad results.... finally with a good builder my motor have produced great results and cost me a bundle to acheive. like i said before if i would of listend to the builders who actually know i would probley have 3 bikes in my garage instead on one.

[GoFast.....]

this is a good thread with plenty of good information.  Rather than just saying "post your build details and an expert will tell you what to do", why not tell us how we too can become experts.  I think the general thing this thread lacks is a way for the novice engine builder to tie together this information on how it it may affect them and their build. There's been plenty of talk about head flow and TB flow, but no posted examples of what a stock '06 and up head flows at various lifts or what typical flow rates for mild porting and full performance porting. I used the '06 and up heads as an example since most are looking for 96" and up upgrades, but the same information should be listed for the older castings.  Furthermore, the traffic cop in all that air flowing equation (cams), really hasn't been touched on that much either. 

I also think that it should be stressed more that flow rates vary depending on the test pressure method (as Max insinuated in post #2).  A novice may look at his head flowing a maximum of 150cfm (at 10") and be upset that his buddy's heads flowed 235cfm (at 28").  Without putting things into context the information can be confusing. 

jmho,
mayor

Mayor maybe this will help novices.

I pick a number I want to hit with my builds and then start working back. Lets say I want to hit 115 hp and tq with a 96 plate form. The first thing I do is studying dyno sheets of people that have done it and have gone before. IF you haven't been there then you do not know how to get there. I personally will study dyno sheets on various sites Latus has a huge amount and the old htt. I then begin to study the three or four sheets in detail and begin to talk with them.

I also begin to talk to the cam people who make the cams like Bob Wood, Mike Roland.TMan. Brain Nallin and then tell them my goal.

I then talk to  the heads porter. He has to be a guy who can make serious power. This is not the place to cut corners. If the head can't flow it it make no difference what the stick is. There are a number of head porting guys on Htt that can get ur done.

I then talk to the TBs guys and get his recommendation.

I then talk to people that know pipes comes to the pipe which is also a study time in the dyno section. I TELL YOU WHAT THIS IS SERIOUS STUFF AND ENGINE BUILDING HAS BECOME A LAND OF THE SPECIALIST.

This sometimes can be a long process or you can call a guy and just order a whole package deal which is what most people should do. 100 110 115 120 pick your HP and buy the package. I personally enjoy the journey

The next thing is the assembly. I have learned the more rushed I am the more mistake so I take my time.

The next thing is the tune.I would drive 500 miles to have my bike tuned by a "Master Tuner". I love the TMax but adjusting  the ignition on a dyno is getting the most out of your build.

I am sure I missed something that others can jump in on

[se]

I pick a number I want to hit with my builds and then start working back. Lets say I want to hit 115 hp and tq with a 96 plate form. The first thing I do is studying dyno sheets of people that have done it and have gone before. IF you haven't been there then you do not know how to get there. I personally will study dyno sheets on various sites Latus has a huge amount and the old htt. I then begin to study the three or four sheets in detail and begin to talk with them.

I also begin to talk to the cam people who make the cams like Bob Wood, Mike Roland.TMan. Brain Nallin and then tell them my goal.

I then talk to  the heads porter. He has to be a guy who can make serious power. This is not the place to cut corners. If the head can't flow it it make no difference what the stick is. There are a number of head porting guys on Htt that can get ur done.

I then talk to the TBs guys and get his recommendation.

I then talk to people that know pipes comes to the pipe which is also a study time in the dyno section. I TELL YOU WHAT THIS IS SERIOUS STUFF AND ENGINE BUILDING HAS BECOME A LAND OF THE SPECIALIST.

This sometimes can be a long process or you can call a guy and just order a whole package deal which is what most people should do. 100 110 115 120 pick your HP and buy the package. I personally enjoy the journey

The next thing is the assembly. I have learned the more rushed I am the more mistake so I take my time.

The next thing is the tune.I would drive 500 miles to have my bike tuned by a "Master Tuner". I love the TMax but adjusting  the ignition on a dyno is getting the most out of your build.

I am sure I missed something that others can jump in on



[/quote]

when you see the smile on their face when they wack the throttle on a finely tuned and built machine ... ..
also i know that we are talking about t/b but one thing also over looked is the pipe you said it "SERIOUS STUFF" it can make or break a build.

a lot of packages that people sell do not produce to the maximum because people scrimp on the tune the tune is the finale of a build go to a good tuner and you will feel the diffrence.

[GoFast.....]

<<There are two kind of engine builders. Builders and Master Builders. I'm a part of the second group.>>

GoFast -

So you are a master builder?   

What is your shops name and where are you located?  Do you have customer dyno's of the various builds you have done?

My family owned and operated a Harley Shop for years in Scottsbluff Nebraska, It was called Bluffs Cycle Center. Ever tried to sale a Shovelhead Harley. m50 125, 250 junk sprint built by AMF bowling equipment in the winter to to pay the bills. We raced a Harley Sporster out of our shop in the 70s and 80s . I'll post a picture of the first chooper my brother and I built in our shop. He was 18 and I was 16. 38 years ago, We thought it was pretty "masterful" even at that age.


Now Lets get back to TBs, because I am still all about learning and growing

Here is my first chopper that I built38 years ago at the age of 16 in 1970. If it kind of looks like a Green Peter Fonda chooper. Well when you are raised in a Harley shop and you see the movie. The next day you were building one. I'm the good looking one on the left

[CraigArizona85248]

MAN!  I love that bike!  Sorry.... off topic... back to our regularly scheduled program...

[skyhook]

how big a tb did the pan/shovel need?

[GoFast.....]

how big a tb did the pan/shovel need?

Pans where to slow to care, We were racing Sporties with telton carbs, stroked motors, sifton -- cams and dykes Jugs and NO electric start. Had to be a Man to Start them. Running in the low 12s in the early 70s

[skyhook]

I hear ya buddy...my first ride was an '69 xl, weld-on hardtail, 12 over girder, magneto, 5 wire, battery eliminator, iron cross taillight, etc....my leg still hurts from kicking and that was a long time ago

[Admiral Akbar]

<<There are two kind of engine builders. Builders and Master Builders. I'm a part of the second group.>>

GoFast -

So you are a master builder?   

What is your shops name and where are you located?  Do you have customer dyno's of the various builds you have done?

Sean

Did Gofast say really was this?  TFF. I think he's baiting you... which might make him a master ...

Max

[ederdelyi]

OH MY!

Hmmm, I'm a pretty good fisherman. Does that make me a master ...

Naw, that's spelled b-a-i-t-e-r. :>)

I've built more than a few motors in my time, but that don't necessarily make one a "master" builder. My hat is off to those that truly are. But hey, attitude has to count for something, i guess. "I think, therefore I am". Good luck with that one, should work out real well for ya!

[FLTRI]

Gofast,
AFAIK a master engine builder is way more than a guy who can effeciently assemble an engine. You mention you search out facts and recommendations of the knowledgable people you trust, admire, and have confidence in their opinions. I believe these are the masters, the guys who break new ground for power, understand airflow, laminar effects, etc, and have the equipment to prove out theories and ideas and introduce new concepts to the industry.
Not saying you aren't a great assembler, but I'm not sure that "master" is the correct term, that's all.
JMHO, Bob

[Mike52]

This looks like it's turned into a pissing match and an ego trip over simple terminology, the use of the word Master.     If this thread doesn't get back on track discussing throttle bodies, I will personally go in and delete every post not on the subject or better yet delete the entire thread and you will lose all the decent info(if there is any). Stop the pissing and moaning, Barry go to your room for a time out and chill.  Enough said.

Mike

[tireater]

I'm going to order the 55mm from HP inc today for my 103" build...I'll get it dynoed at the end of the month....(back on track)

[ederdelyi]

A "peace offering" :>)

http://www.revtronix.com/techinfo/calculators/throttlebody.php

Keep in mind that the calculated airflow if you choose the CFM option is in SCFM, i.e. no test pressure is associated with it. The CFM is as one would see when measuring airflow on an engine dyno equipped with an air turbine. While not the best estimator I've ever played with, it's close enough to be usable. You have to be HONEST with your input data, unrealistic VE values will skew the results all out of proportion. Most street ridden HD builds will be doing *extremely* well if they get anywhere near 100% VE .... BWTFDIK, I'm not a master :>)

EDIT: Also the HP shown is CRANKSHAFT power. When calculating TB and injector sizes one must remember that the TB and injectors must supply the fuel and air for the *actual* power being developed, which is at the crank. The power wasted in the drivetrain ... well, your mission Mr. Phelps ...

[Faast Ed]

Tireater, if (and that is a big if) I go with a bigger TB this winter, it's going to be the 51.  That already will be a big jump from my stock 46, plus the fact that the design is better than HD's (the better design alone will flow better, not just the bigger size).
Me thinks going too big might negatively affect the ranges where I spend most of my time (based on the experience of some of the other posters).

Ed E, Nice calculator!  Thanks for posting it, I will save it for when I can better figure out what values to add in the appropriate boxes. Don't look like anything I can guess at, and still be accurate.

[GoFast.....]

I'm going to order the 55mm from HP inc today for my 103" build...I'll get it dynoed at the end of the month....(back on track)

tireater what is the build sheet on your bike again

[ejk_dyna]

 <<BWTFDIK, I'm not a master :>)   >>     
 
Ed you gotta start posting more.....and what were the reasons that you don't like the grooves???

[GoFast.....]

I'm going to order the 55mm from HP inc today for my 103" build...I'll get it dynoed at the end of the month....(back on track)

I think most 103 which is where most guys are going to be running are going to fall into the 51mm to 55mm. The diffrence will be in the amount of flow in the heads and the selection of cama

[ederdelyi]

Hmmm ... that's interesting. Makes one wonder how other motors seem to be able to produce comparable power outputs with TB's that would appear "small" compared to what most seem to be advocating here. For instance:

GM LT4 5.7 litre (350 CI) motor. 330 HP @ 5800 RPM, 340 TQ (I don't remember at what RPM off the top of my head). Uses a dual 48mm TB setup.

That setup flows about 620 - 650 CFM. And the HP/CI (.94) is pretty much in line with the "average" HD build as well as the estimated VE's.

If we cut the 350 motor displacement by 2/3, that would be about 116 CI ... how big of a TB do you folks think we would need if we kept the VE and power levels the same? Unless the GM engineers are using "different air" than us HD guys ... think about it.

 

Remember, the TB is only an air valve used to contol the amount of air needed by the motor to produce the power needed to move the vehicle at the speed desired. It should do that with the least restriction possible for *maximum* power across the entire powerband. In theory, you should be able to use a TB the size of a trash can lid if the runners/ports/valves are sized correctly and the ECM can meter the fuel correctly for a given area change of the TB!

[GoFast.....]

Hmmm ... that's interesting. Makes one wonder how other motors seem to be able to produce comparable power outputs with TB's that would appear "small" compared to what most seem to be advocating here. For instance:

GM LT4 5.7 litre (350 CI) motor. 330 HP @ 5800 RPM, 340 TQ (I don't remember at what RPM off the top of my head). Uses a dual 48mm TB setup.

That setup flows about 620 - 650 CFM. And the HP/CI (.94) is pretty much in line with the "average" HD build as well as the estimated VE's.

If we cut the 350 motor displacement by 2/3, that would be about 116 CI ... how big of a TB do you folks think we would need if we kept the VE and power levels the same? Unless the GM engineers are using "different air" than us HD guys ... think about it.

 

Remember, the TB is only an air valve used to control the amount of air needed by the motor to produce the power needed to move the vehicle at the speed desired. It should do that with the least restriction possible for *maximum* power across the entire powerband. In theory, you should be able to use a TB the size of a trash can lid if the runners/ports/valves are sized correctly and the ECM can meter the fuel correctly for a given area change of the TB!

I do not know if compairing Chevy engines to Harleys. A 330hp to me is on the small side in the area of heads and cam so just like a Harley that engine will not be able to take advantage of a larger TB. The acid test is dynoing it with one and then another and this thread has plenty examples of the increases gained by the larger TB with the builds that can take advantage of because of greater heads and cams

[ederdelyi]

My bad! I tried to keep it simple ... which of the big words don't you understand? :>) As Roseanna Danna would say ... never mind! There are some folks out there who will understand what I was getting at, and that's all I intended the post to accomplish.

[Faast Ed]

If we cut the 350 motor displacement by 2/3, that would be about 116 CI ... how big of a TB do you folks think we would need if we kept the VE and power levels the same? Unless the GM engineers are using "different air" than us HD guys ... think about it.

Doing the same to your quoted HP/TQ numbers would be 110/113, not a bad target to shoot for.
It seems that a single 48mm would be more than enough in this example? (only had two on the whole 3/3rds)

Are you by any chance a "master"? 

[ederdelyi]

>>It seems that a single 48mm would be more than enough in this example?>>

At these power levels, yes. If you use the link to the calculator that I posted and use VE's in the 87 to 90 range you will see that there is only a 1.5 HP loss and a .97 kpa pressure drop with a single 48mm TB. Even at 100% VE the power loss is only 2HP and the pressure drop is 1.17 kpa. Will a bigger TB hurt performance? Not really. There will likely be a diiference in throttle response and tuning could be more involved depending on how much bigger the TB really is.

*IF* you have a motor that is capable of high VE's at higher RPM's and you intend to use that capability then a large TB will certainly allow one to get the "last drop from the grape". If you have a 95, 100, 103, 107 ... whatever displacement motor that is like most street driven HD's out there then a large TB will likely be of little value. It depends on what your expectations are and how you intend to use the motor. The upside to this is that unlike a carb that is too big, too large of a TB will likely only hurt your pocketbook! :>)

[FLTRI]

>>It seems that a single 48mm would be more than enough in this example?>>

At these power levels, yes. If you use the link to the calculator that I posted and use VE's in the 87 to 90 range you will see that there is only a 1.5 HP loss and a .97 kpa pressure drop with a single 48mm TB. Even at 100% VE the power loss is only 2HP and the pressure drop is 1.17 kpa. Will a bigger TB hurt performance? Not really. There will likely be a diiference in throttle response and tuning could be more involved depending on how much bigger the TB really is.

*IF* you have a motor that is capable of high VE's at higher RPM's and you intend to use that capability then a large TB will certainly allow one to get the "last drop from the grape". If you have a 95, 100, 103, 107 ... whatever displacement motor that is like most street driven HD's out there then a large TB will likely be of little value. It depends on what your expectations are and how you intend to use the motor. The upside to this is that unlike a carb that is too big, too large of a TB will likely only hurt your pocketbook! :>)

You elequently took the words right out of my mouth, Ed.

[Faast Ed]

There will likely be a difference in throttle response and tuning could be more involved depending on how much bigger the TB really is.

Slower revving (one poster had mentioned). Not having been thru an overly large TB experience (and for a year now tempted to buy one), this point is nagging me.

While I spend most of my time cruising (aggressive cruise is common), I also like the best blast I can get from my babycam set-up.  IF I do go up in TB size, it will surely be the smallest step up.
Either the 51mm or possibly just reworking my stock TB.   Hel, I might still leave it alone.

In case you aren't familiar, I have an 08 103", 54's Mild port (1.9 intake stock exhaust), Fatcat, SERT.   I likely don't need a bigger TB.

Thank you for sharing your knowledge.

[HDdawg2008]

Been reading these posts for a while now, and I have come to the conclusion that no one will ever have the same opinion, so I am just going to use facts.  I've checked out dyno runs from several sites, Wood Performance, T-man Performance, Horsepower Inc., Joe's Cycle and have found nice gains using larger throttle bodies.  I have also talked to some of these performance shops, and have found that they do not recommend a larger throttle body when not needed.  They have all done comparisons and know what they are talking about.  I called Horsepower Inc. today and was told that based on what I have done so far to my bike, that I would not benifit from a larger throttle body at this time and to call back when I changed a few things.  Thought that was pretty cool considering they manufacture them and they weren't just looking to make a sale.  Try finding that elsewhere. I think this topic should end, I think we should call the experts before guessing whether it is needed or not.   

[FLTRI]

"I think we should call the experts before guessing whether it is needed or not." 

[Don D]

I believe this was covered well.
Ask the tuner! MAP pressure is their sign.

Quote from Grock
MAP almost always will start to drop from anywhere from 4100 to 4700 on a decent 95 and higher build with the Delphi. BUT.... the difference in HP is maybe 3 to 4 HP with a cam like the 37. And some of that may be caused by front to rear fuel reversion at high R's. So not a big deal on the TB size. Remember that you aren't hanging around in the 4000 to 5000 rpm range for very long anyway. The most that you can bore out of the stock Delphi is about 3mm MAX, and although that will move your MAP drop up a few hundred R's, it doesn't completely solve the issue you are having. Again, I'm not calling it a problem because it really isn't on a cam like the 37. This is for up to 2005 models. The 06's have their own problems in this arena, but some of those are influenced more by the smaller injector size that simply will not support high HP engines because of the limited pulse width. This, COMBINED with the TB bore, WILL cause problems on 06's that are trying to make big power.

[Faast Ed]

I called Horsepower Inc. today and was told that based on what I have done so far to my bike, that I would not benifit from a larger throttle body at this time and to call back when I changed a few things.

Perfect!  
Now if you can elaborate on "What was done so far to your bike", it would be helpful to some of us less experienced folks, to help gauge whether we need one, or are in the same boat as you (not needing one).  This type of banter is why we are all here. To gain from others experiences.

Aw heck,....  I believe that I have already learned enough from this string to realize that a larger TB would not benefit me enough to justify it.

[Faast Ed]

I think this topic should end, I think we should call the experts before guessing whether it is needed or not.   

I guess we really don't need a message board then, we'll just call our local indy with all of our question.  LOL

Hey Brian (Valley Racing), I hope you have a LOT of time on your hands.  I am gonna quit posting and start calling you everyday!

[HDdawg2008]

07 Street Glide with Vance and Hines, TW6-6 cams, Air cleaner and stock compression.  Told me to call back if I gain some head work, a larger cam and added compression.  They didn't even recommend reworking the stock throttle body for this build.  But check out their dyno run on the 2005 88 ci Dyna.  www.horsepowerinc.net/products/dyno-testing.  Wow!  Who's posting numbers like that?

[Don D]

ED
I suspect both Valley and or Larry can give you a definitive answer. The MAP pressure readings at sustained high rpm would tell the story. BTW same sort of scenerio holds true for small injectors (not saying yours are I have no idea...just saying) when the duty cycle becomes very high at high rpm and a proper mixture can not be accomplished.

[fuzznut5197]

front to rear fuel reversion at high R's

What causes that?

[ederdelyi]

>>What causes that? <<

It's a "benefit" of the odd-fire configuration (45 deg. V-Twin) and has to do with the pulse width needed at higher RPM coupled with the "Y" manifold configuration. In essence, one injector is still spraying fuel that will interact with the other cylinder. Wouldn't happen in an individual runner setup.

[fuzznut5197]

It's a "benefit" of the odd-fire configuration (45 deg. V-Twin) and has to do with the pulse width needed at higher RPM coupled with the "Y" manifold configuration. In essence, one injector is still spraying fuel that will interact with the other cylinder. Wouldn't happen in an individual runner setup.

Ah, I see, sort of! In this higher rpm range, with regard to induction pulses, is the rear cyl seeing a "peak" while the front cyl sees a "trough", and the injector is trying to "fix" the situation?

[ederdelyi]

A 45 deg. V-Twin has an inherent primary imbalance. Contemplate the 315-405 degree firing order and then consider the ramifications on an induction system with a common plenum and *very* short ports and runners. This has always been a problem, even with carbed versions of this motor. Cylinder trim is now possible with the introduction of EFI, but there are limits. At high RPM and with injector sizes that will give good low RPM driveability the duty cycle becomes large enough that it's not possible to provide enough fuel in the time allotted without some of the fuel intended for one cylinder to end up being added to the fuel for the other cylinder as well. The "Y" manifold sucks (pun intended) from a performance standpoint. The 45 deg. angle and the location of the ports makes it extremely challenging to produce a manifold that can make use of the tuning so common on modern EFI vehicles. That, coupled with an extremely short intake port length is one of the factors that makes it more challenging to produce high power levels, even at moderate RPMs.

EDIT: OOPS! Aren't you over your quota of questions? :>) Ignore this post until tomorrow :>)

[GoFast.....]

I'm going to order the 55mm from HP inc today for my 103" build...I'll get it dynoed at the end of the month....(back on track)

I think most 103 which is where most guys are going to be running are going to fall into the 51mm to 55mm. The diffrence will be in the amount of flow in the heads and the selection of cama

I still think the testing Larry did was a slame dunk for me. Ather 100tq and 100hp I'm looking for more air from a TB
Larry posts of old HTT

in your opinion what is the biggest difference in this combo compared to what you have been building?
anything different in the way the heads were done?
Didn't do anything special with the heads. The biggest hurdle is that stock throttle body IMO. Haven't seen any big #'s with a stocker. The older 2-piece were a lot better. This new style just don't get it. It's OK for what most people want- 100/100 but for the guys that want the big #'s it would be the 1st thing I changed. And that goes for any cam not just this one.
The 1 piece TB flows about 235 @ 28". The heads on this bike were flowing 276 with a 1" radius fixture on the head. With the stock TB [ported] it pulled 245 & with the HP51 it pulled 276. If you listen to that throttle body when it's on the flowbench it sounds terrible. Probing it you find out why. Looking at the cfm #'s doesn't tell the whole story. This was our biggest problem with this build IMO. But that's what happens when the customer doesn't want to spend the money upfront. After riding it all last year come winter he said 'do whatever it takes'. He's a lot happier now. If a customer doesn't want to change out the TB for a better one I keep the cams on the small side because I haven't seen one yet that made it over 110. They usually come in at 100-106 hp. 

[fuzznut5197]

OOPS! Aren't you over your quota of questions? :>) Ignore this post until tomorrow :>)

Rats, you caught me! Apparently, your memory has not retired.  

Thanks Ed, although I don't have an EFI bike (oops, should I say that in an EFI thread?), I have been trying to understand the upper rpm cylinder imbalance that my motor has been blessed with.
Using a wego III, the rear cyl becomes a manifold hog and the front gets the short end of the stick.
So, if you have some time, can you do a quick calculation for me? If a typical mass and drag coefficient are given, how far, in meters, can an average person throw a Y manifold?          

[FLTRI]

"the rear cyl becomes a manifold hog and the front gets the short end of the stick"

Which is why the myth of the rear cylinder running hotter than the front is just that, a myth, unless we are talking about cruising thru town.
A long time ago (1982-4) we used EGT probes to measure exhaust temp. This was before wideband O2 sensors were used and affordable.
Through that testing we discovered the rear got the cooling fuel feed while the front was going lean.
Now let me toss this in:
On a dyno the rear cylinder runs leaner than the front. Go figger. Any guesses as to why?
As a tuner it helped to know these things.
Bob

[fuzznut5197]

On a dyno the rear cylinder runs leaner than the front. Go figger. Any guesses as to why?

Hey my front cyl was leaner on the dyno too. Is that an efi only phenom?

Hmm, standing still vs on the road. Is the front jug's exhaust gas velocity higher
on a dyno? Front O2 sensor cooler on the road?

[FLTRI]

Whoops, forgot to mention this applies mainly to 2into1 systems.

[TQer]

Dont want to take this too far off subject but what about the case of dual runner alpha-n systems? Going from a 38 to a bored 42? Say bout 10.25 cr W/590 lift and velocity ported heads (currently there). Worth it? Pros vs cons? I've visited it before on the old HTT. But what the heck..... lets go for it again. Twist my arm or tell me forget it

[GoFast.....]

"the rear cyl becomes a manifold hog and the front gets the short end of the stick"

Which is why the myth of the rear cylinder running hotter than the front is just that, a myth, unless we are talking about cruising thru town.
A long time ago (1982-4) we used EGT probes to measure exhaust temp. This was before wideband O2 sensors were used and affordable.
Through that testing we discovered the rear got the cooling fuel feed while the front was going lean.
Now let me toss this in:
On a dyno the rear cylinder runs leaner than the front. Go figger. Any guesses as to why?
As a tuner it helped to know these things.
Bob

Which is why the myth of the rear cylinder running hotter than the front is just that, a myth
Bob. your swinin up stream on this one and I would like to here more, Two reasons why people thought it ran hotter was one less fuel to the rear caused a lean condtion which makea a cylinder run hotter but also the front cylinder blocks the back one from the air

[FLTRI]

"Bob. your swinin up stream on this one and I would like to here more"
As I explained in post: "Through that testing we discovered the rear got the cooling fuel feed while the front was going lean."

Here's a little something to consider:
Take a typical HD V-twin as used in a drag race. When the bike launches off the line the intake track's AF mixture is moving perpendicular to the track while the bike is talking off. Which cylinder will get favored with more AF mixture? Also there is more fuel stuck to the rear cylinder part of the manifold.
Now put a 200hp v-twin in the same situation and the problem is exacerbated, big time. When the bike launched the front cylinder went lean and the rear went rich.....until 60ft, then you saw the g-forces wane and the AF balance start to normalize and by 1/8 mile the AFR was fairly balanced. We know it was happening this way becasue it did not exhibit that anomoly on the dyno.

This is but just a small bit of what can be learned from measuring what actually happens.

[se]

"Bob. your swinin up stream on this one and I would like to here more"
As I explained in post: "Through that testing we discovered the rear got the cooling fuel feed while the front was going lean."

Here's a little something to consider:
Take a typical HD V-twin as used in a drag race. When the bike launches off the line the intake track's AF mixture is moving perpendicular to the track while the bike is talking off. Which cylinder will get favored with more AF mixture? Also there is more fuel stuck to the rear cylinder part of the manifold.
Now put a 200hp v-twin in the same situation and the problem is exacerbated, big time. When the bike launched the front cylinder went lean and the rear went rich.....until 60ft, then you saw the g-forces wane and the AF balance start to normalize and by 1/8 mile the AFR was fairly balanced. We know it was happening this way becasue it did not exhibit that anomoly on the dyno.

This is but just a small bit of what can be learned from measuring what actually happens.

how do you fix the problem???

[GoFast.....]

"Bob. your swinin up stream on this one and I would like to here more"
As I explained in post: "Through that testing we discovered the rear got the cooling fuel feed while the front was going lean."

Here's a little something to consider:
Take a typical HD V-twin as used in a drag race. When the bike launches off the line the intake track's AF mixture is moving perpendicular to the track while the bike is talking off. Which cylinder will get favored with more AF mixture? Also there is more fuel stuck to the rear cylinder part of the manifold.
Now put a 200hp v-twin in the same situation and the problem is exacerbated, big time. When the bike launched the front cylinder went lean and the rear went rich.....until 60ft, then you saw the g-forces wane and the AF balance start to normalize and by 1/8 mile the AFR was fairly balanced. We know it was happening this way becasue it did not exhibit that anomoly on the dyno.

This is but just a small bit of what can be learned from measuring what actually happens.

Ok Bob Then explain why for years people came to beleive that the back one runs hotter

[skyhook]

don't know what happened to my post from earlier today...grrrr...but I'm not bitter about it...my main guru has a dual runner tb for delphi...may eliminate some of the issues mentioned in previous posts...really like this guy...reminds me of myself 15 years from now...must reiterate on topic and say one piece t/b are crap...I'd lose it before I did headwork, cam, big bore on '06 and later!!!!!...anyone tells you not to go aftermarket is just trying to justify their cheapness on their own build (imo, of course)...gotta let them puppies breathe!!!!...lemme hol' a square, blood

and I've switched up today...will now be designer/wrench/apprentice tuner/asst manager/general a-hole @ mike cat's cyle, kenner, la....anyone with cojones to show @ donaldsonville, la 1/4 mi LET ME KNOW

[Admiral Akbar]

"Ok Bob Then explain why for years people came to beleive that the back one runs hotter"

They do? Why would they believe this?

Max

[Faast Ed]

Cuz they "assumed" the wind was being blocked from it and cooling it less?

A few years ago on HTT there were posts done with heat camera photos proving the front one ran hotter at the dragstrip.
Anybody else remember that string?

[fuzznut5197]

As I explained in post: "Through that testing we discovered the rear got the cooling fuel feed while the front was going lean."

Here's a little something to consider:
Take a typical HD V-twin as used in a drag race. When the bike launches off the line the intake track's AF mixture is moving perpendicular to the track while the bike is talking off. Which cylinder will get favored with more AF mixture? Also there is more fuel stuck to the rear cylinder part of the manifold.
Now put a 200hp v-twin in the same situation and the problem is exacerbated, big time. When the bike launched the front cylinder went lean and the rear went rich.....until 60ft, then you saw the g-forces wane and the AF balance start to normalize and by 1/8 mile the AFR was fairly balanced. We know it was happening this way becasue it did not exhibit that anomoly on the dyno.

This is but just a small bit of what can be learned from measuring what actually happens.

So why does this happen with mainly 2-1 systems?

[Midnight Toker]

Thanks Bob, I appreciate your knowledge, I had never considered the g-force aspect of the fuel delivery.
To ederdelyi, thanks for being here, glad to see your back and I hope you stay. I appreciate your in-depth knowledge and explanations.

MT.

[Midnight Toker]

don't know what happened to my post from earlier today...grrrr...but I'm not bitter about it...my main guru has a dual runner tb for delphi...may eliminate some of the issues mentioned in previous posts...really like this guy...reminds me of myself 15 years from now...must reiterate on topic and say one piece t/b are crap...I'd lose it before I did headwork, cam, big bore on '06 and later!!!!!...anyone tells you not to go aftermarket is just trying to justify their cheapness on their own build (imo, of course)...gotta let them puppies breathe!!!!...lemme hol' a square, blood

and I've switched up today...will now be designer/wrench/apprentice tuner/asst manager/general a-hole @ mike cat's cyle, kenner, la....anyone with cojones to show @ donaldsonville, la 1/4 mi LET ME KNOW

Wow...I do have 'cojones' but I'm not going to Louisiana to show ya..LOL. 

[skyhook]

maybe meet 1/2way?...loser buys food and grog...open invite to all


here's a pic of the dual runner delphi

[attachment removed after 60 days by system]

[GoFast.....]

don't know what happened to my post from earlier today...grrrr...but I'm not bitter about it...my main guru has a dual runner tb for delphi...may eliminate some of the issues mentioned in previous posts...really like this guy...reminds me of myself 15 years from now...must reiterate on topic and say one piece t/b are crap...I'd lose it before I did headwork, cam, big bore on '06 and later!!!!!...anyone tells you not to go aftermarket is just trying to justify their cheapness on their own build (imo, of course)...gotta let them puppies breathe!!!!...lemme hol' a square, blood

and I've switched up today...will now be designer/wrench/apprentice tuner/asst manager/general a-hole @ mike cat's cyle, kenner, la....anyone with cojones to show @ donaldsonville, la 1/4 mi LET ME KNOW

Wow...I do have 'cojones' but I'm not going to Louisiana to show ya..LOL. 

To bad we don't all live in the same city. But a guy who says one peices are crab and says lets go to the strip should be able to  post your dyno and  build sheet and a 1/4 time slip. And you thought I was bad Mike.

[Don D]

maybe meet 1/2way?...loser buys food and grog...open invite to all


here's a pic of the dual runner delphi

Nice
Would be interesting to see how the Delphi injectors, pressure regulator and MAP sensor are integrated to this reworked retrofit MM TB and if he corrected the poor injector angulation. Not sure if IR was the goal why not just buy the BC Gerolomy piece and feed the MAP sensor a common joined source then the Delphi ECU can be utilized not aftermarket. Would have been a lot more simple and that is a well designed high flow piece. Not to wander too far but in terms of airflow the Jims oval TB is also an interesting looking piece, granted not IR and the cross chatter with high pulse width injection is still present.
I hear what you are saying about the 1 piece 06up TB but really it is not a constraint for many of the more mild builds even 103". Or in some cases just a hp or two on top. Your 110" motor is another story bigger pump. BTW who did the MM TB mods?

[PanHeadRed]

Phub, I posted on the old site a while back that there are a few racers around here using the Delphi controller and injectors with the MM TB's. They like it, they commented that the only advantage of the Delphi was the faster processor.

Just say'n.

[Don D]

Cool!
Just seems like a lot of work and another thing I didn't mention the IAC and the retro for that device. On a race bike would not be needed and the MM air bleeds could be utilitized, I suspose. Yeah cool stuff.

[Deye76]

Do tuners have a hard time with "dual throat" set ups? Is it that they don't work well on a short Y manifold? Remember the S&S 2 throat?

[GoFast.....]

maybe meet 1/2way?...loser buys food and grog...open invite to all invite


here's a pic of the dual runner delphi

I would think this would be like super street. You  have to be able to drive it there and back and you have to match up cubic inches.

[GoFast.....]

maybe meet 1/2way?...loser buys food and grog...open invite to all


here's a pic of the dual runner delphi

Here is BC weblink for dual runners //http://www.bcheads.com/fuel.htm

[FLTRI]

Do tuners have a hard time with "dual throat" set ups? Is it that they don't work well on a short Y manifold? Remember the S&S 2 throat?

Actually makes no difference to me as far as tuning as long as it was done correctly, especially as to the MAP sensor. Since the MAP sensor is looking for common manifold pressure the the 2 runners must be made common for the right signal to get to the ECM.

[Don D]

Do tuners have a hard time with "dual throat" set ups? Is it that they don't work well on a short Y manifold? Remember the S&S 2 throat?

Yep I have used the S&S before and got it to work fine on my old superglide, kind of like the HD Holley much maligned and misunderstood, not bad. I can't remember if the S&S was true IR though and the Holley was not.
One problem with tuning the IR with a Delphi ECU is the MAP sensor needs to be from a common 2 cyl source and the BC Gerolomy setup is not but would be easy to adapt. Also the BC unit uses a non-standard TPS IIRC. DTT Wego II or III can negotiate the single cyl. MAP signal and the BC TB TPS, not sure about Tmax.
IR changes the whole ballgame and what may seem like way too big is not due to the manifold pulsation and time between intake cycles. Take a look at an old Ferrari V-12, tiny motor and see the 6 -2 barrels. It works very well and even though this is a dual OHC motor it is not that high rpm. I know OT sorry.

[PanHeadRed]

DH's, I did not get into detail as to how, and why, I just listened as he briefly talked, he was just getting into the conversions and had done 2 maybe three. I will talk with him when I can, and see how it panned out.

[skyhook]

just came back from french qtr, rippin' all the way...good air here and I LIKE it!...gofast here's my sheet...really a mild build...110"... '08 ...570 lift cams ...200ccp...pump gas...5th gear...dj250...sae...I've put 9.5k miles on it in 13 mos

[attachment removed after 60 days by system]

[roadglide65]

just came back from french qtr, rippin' all the way...good air here and I LIKE it!...gofast here's my sheet...really a mild build...110"... '08 ...570 lift cams ...200ccp...pump gas...5th gear...dj250...sae...I've put 9.5k miles on it in 13 mos

If we could postpone this till spring when I get out of all this cold weather I would love to see what what my 110" would do against yours    I'm always up for a good Crayfish Boil and some good Cajun food.

OH and I've only put 12000 on mine in 7 months 

[mtnmotorrider]

That's "craw fish" boil, and Coon Ass food, if you use the proper vernacular!   

[roadglide65]

That's "craw fish" boil, and Coon Ass food, if you use the proper vernacular!   

You know I new I knew I screwed up as soon I posted it. Like I've been told time and time again it not peeee can pie phacan pie.

That's the problem with letting these yamdankes coming down there.   

[Sonny S.]

As I explained in post: "Through that testing we discovered the rear got the cooling fuel feed while the front was going lean."

Here's a little something to consider:
Take a typical HD V-twin as used in a drag race. When the bike launches off the line the intake track's AF mixture is moving perpendicular to the track while the bike is talking off. Which cylinder will get favored with more AF mixture? Also there is more fuel stuck to the rear cylinder part of the manifold.
Now put a 200hp v-twin in the same situation and the problem is exacerbated, big time. When the bike launched the front cylinder went lean and the rear went rich.....until 60ft, then you saw the g-forces wane and the AF balance start to normalize and by 1/8 mile the AFR was fairly balanced. We know it was happening this way becasue it did not exhibit that anomoly on the dyno.

This is but just a small bit of what can be learned from measuring what actually happens.

So why does this happen with mainly 2-1 systems?

[Deye76]

Do tuners have a hard time with "dual throat" set ups? Is it that they don't work well on a short Y manifold? Remember the S&S 2 throat?

Yep I have used the S&S before and got it to work fine on my old superglide, kind of like the HD Holley much maligned and misunderstood, not bad. I can't remember if the S&S was true IR though and the Holley was not.
One problem with tuning the IR with a Delphi ECU is the MAP sensor needs to be from a common 2 cyl source and the BC Gerolomy setup is not but would be easy to adapt. Also the BC unit uses a non-standard TPS IIRC. DTT Wego II or III can negotiate the single cyl. MAP signal and the BC TB TPS, not sure about Tmax.
IR changes the whole ballgame and what may seem like way too big is not due to the manifold pulsation and time between intake cycles. Take a look at an old Ferrari V-12, tiny motor and see the 6 -2 barrels. It works very well and even though this is a dual OHC motor it is not that high rpm. I know OT sorry.

An engine builder I know had one(S&S 2 throat) on his 93" shovel. He got it to run good after he removed the wall in the manifold.

[jmorton10]

MAN!  I love that bike!  Sorry.... off topic... back to our regularly scheduled program...

Me too, here was my first around 1970

http://www.pbase.com/jmorton10/image/23429104

5" stroke, 92 inches with stroker plates......

Started as a stock 1957 Police Pan......

~John

[GoFast.....]

MAN!  I love that bike!  Sorry.... off topic... back to our regularly scheduled program...

Me too, here was my first around 1970

http://www.pbase.com/jmorton10/image/23429104

5" stroke, 92 inches with stroker plates......

Started as a stock 1957 Police Pan......

~John

That is a beautiful rigid pan head, Nice enought to be in a mag. I forget, What kind of Carb is that

[FLTRI]

Looks suspiciously like an SU? LOL!

[hrdtail78]

If I was on the fence of a larger TB or not.  I would start by looking at the fitment of the stock TB.  Some of them fit terribly.  When assembling an engine (trying to stay with correct, accepted terms) I perfer to have the TB or manifold handy rather than at the customers house.  My point being this.  A smaller TB with correct port matching will deliver a better slug of air into an engine over a bad port matching slightly larger TB.

[FLTRI]

If I was on the fence of a larger TB or not.  I would start by looking at the fitment of the stock TB.  Some of them fit terribly.  When assembling an engine (trying to stay with correct, accepted terms) I perfer to have the TB or manifold handy rather than at the customers house.  My point being this.  A smaller TB with correct port matching will deliver a better slug of air into an engine over a bad port matching slightly larger TB.

Boy do I agree!
Port matching is as old as the hills yet is ignored by some shops yet, IMO is absolutely necessary to do a proper job IMO. After all the customer is hiring a shop (indy or dealer) to do performance work. IMO performance work cannot be accomplished properly with mismatched port to intake manifold fitment.
Kinda real basic to the definition of performance.

[GoFast.....]

You can open the butterfly by the throddle and use a flash light and see if they match. With the older two peice and Carb manifold you can stick your finger in there and check to make sure they match.

[Hoist!]

Youze are all talking about peak numbers and small gains from changing TB size. So you can argue that all day! What about the rideability?  Is that not a seat-of-the-pants REAL performance gain too? On my hot rodded 110, it was designed for a 58mm HPI TB and used it with a Doherty Power Pakk A/C. Peformed very well at peak, but had a dip and ramped up at low RPM's. We tested some things, one of which was going to a 62mm HPI TB with their hi flo A/C. Not much difference on peak numbers, but it cleaned up the whole bottom, and raised TQ substantially, and straightened up the curve in the lower RPM range. Went from 89 Ft-LBS @ 2000 to just over 100! You bet your ass TB selection is important!

Hoist!

[Admiral Akbar]

Well so much for smaller being higher velocity and making more low end torque..  Max

[Hoist!]

Well so much for smaller being higher velocity and making more low end torque..  Max

All depends on the flow characteristics of the top end. The CVO 110 needs GOBS of flow to wake it up. Unless you modify the heads by welding the ports, changing valve size, and increasing that velocity throughout, the increased velocity in 1 area doesn't really do much for ya. Match the flow characteristics of the heads with the rest of the intake, exhaust, and cam timing, and you have a whole new ballgame! Most have not tested or embraced the 110. I love mine! But I'm not talking HD's POS stock 110 either here, but a slightly modified version thereof!

Hoist!

[Admiral Akbar]

Well,

I guess it's OK as long as Donny didn't work on it..  Max

[Hoist!]

Well,

I guess it's OK as long as Donny didn't work on it..  Max

HeHe!!! OK! Well Donny didn't, whoever that is!

Hoist!

[geezerglide]

Well,

I guess it's OK as long as Donny didn't work on it..  Max

HeHe!!! OK! Well Donny didn't, whoever that is!

Hoist!

Hoist,

I am assuming MaxHeadflow is referring to Donny Petersen, but I could be wrong.

Its good to see you over on this board, I see you more frequently. lately.

geezerglide

[Hoist!]

Well,

I guess it's OK as long as Donny didn't work on it..  Max

HeHe!!! OK! Well Donny didn't, whoever that is!

Hoist!

Hoist,

I am assuming MaxHeadflow is referring to Donny Petersen, but I could be wrong.

Its good to see you over on this board, I see you more frequently. lately.

geezerglide

He geezer, didn't know you were over here too! Thanks for saying hey! Just signed up yesterday! Very cool tech site. I'm glad Coyote steeered me over here! I thought he mighta been referring to DP, but still trying to get a flavor for personalities here. So, not sure if something's sarcastic yet,  I'll err on the side of caution! (for now anyway!)

Hoist!

[GoFast.....]

Welcome to the best Harley Tech Site on the internet

[Admiral Akbar]

HeHe!!! OK! Well Donny didn't, whoever that is! 
Hoist!

Hoist,

I am assuming MaxHeadflow is referring to Donny Petersen, but I could be wrong.

Its good to see you over on this board, I see you more frequently. lately.

geezerglide

Heck I you don't know who Donny is then you're all right in my book..  Max

[Don D]

Unless you modify the heads by welding the ports, changing valve size, and increasing that velocity throughout

Or just take a set of the old tried and true 99-04 TC stock heads and rework them, no welding needed, bigger valves are needed however to feed that motor that is 25% bigger than what the heads were designed for. The 110 heads can be made to work well too without welding. This has been discussed on the CVO forum  

[uglyDougly]

  Welcome Hoist, I'm not your official greeter but I'd like to take a look at your big-throttle example and try to shed some light. Since this thread is about throttle sizing.

 Hoist said; 'it was designed for a 58mm HPI TB' and then; 'going to a 62mm HPI TB with their hi flo A/C. Not much difference on peak numbers, but it cleaned up the whole bottom, and raised TQ substantially'

 I don't accept that increased velocity across the TB has any beneficial effect on cylinder fill, (and there are many who will disagree) but the opposite, decreasing velocity, most certainly, isn't true.

 The only reason for an increase in torque at low RPM is tuning. One of your dyno results had to have been incompletely/improperly calibrated. I'm not attacking your tuner either, it's just that the torque characteristics of your build is the result of everything after the TB/manifold and the only thing the TB.
/manifold can do is take away power. TB restriction starts at the power peak (maximum, total air flow) and increasing restriction will take away farther down the RPM band. (Such as closing the throttle.)

  If you look at 20%, 40%, 60%, 80%, & 100% throttle dyno charts (after the AFRs are finalized) you will see that the torque is exactly the same at the lowest RPM, and each increasing throttle position will extend the same torque curve out to a higher RPM. If opening the throttle doesn't increase the low RPM torque, how can installing a larger throttle increase the low RPM torque?
 I've attached a dyno chart as an example.

 Doug

[attachment removed after 60 days by system]

[Admiral Akbar]

Good stuff Doug.

I'm not sure if you can get the injector timing from the fuel system but did the spray time also appear the same? Max

[Hoist!]

 Welcome Hoist, I'm not your official greeter but I'd like to take a look at your big-throttle example and try to shed some light. Since this thread is about throttle sizing.

 Hoist said; 'it was designed for a 58mm HPI TB' and then; 'going to a 62mm HPI TB with their hi flo A/C. Not much difference on peak numbers, but it cleaned up the whole bottom, and raised TQ substantially'

 I don't accept that increased velocity across the TB has any beneficial effect on cylinder fill, (and there are many who will disagree) but the opposite, decreasing velocity, most certainly, isn't true.

 The only reason for an increase in torque at low RPM is tuning. One of your dyno results had to have been incompletely/improperly calibrated. I'm not attacking your tuner either, it's just that the torque characteristics of your build is the result of everything after the TB/manifold and the only thing the TB.
/manifold can do is take away power. TB restriction starts at the power peak (maximum, total air flow) and increasing restriction will take away farther down the RPM band. (Such as closing the throttle.)

  If you look at 20%, 40%, 60%, 80%, & 100% throttle dyno charts (after the AFRs are finalized) you will see that the torque is exactly the same at the lowest RPM, and each increasing throttle position will extend the same torque curve out to a higher RPM. If opening the throttle doesn't increase the low RPM torque, how can installing a larger throttle increase the low RPM torque?
 I've attached a dyno chart as an example.

 Doug

Thanks for the welcomes gang! Interesting reply and certainly some valid points, and not unexpected at all. It's the typical response when I mention this approach to performance mods on CVO 110's. However, that consistent dip in that dyno chart is EXACTLY what we removed with the larger TB on my bike. No other way til we tried it. My engine was designed by a fairly reknowned builder that worked with HD FI engineers to help develop performance modifications specific to HD's oddball 110 CVO engine. Thru their testing, then our own afterwards, we determined that the CVO 110 needed to get them crappy EPA 255 cams outta there ASAP and get that motor GOBS of flow. The motor's kind of an anomoly, if you would. 2 methods are being used to increase performance. One is the traditional method you guys all speak of here by changing the design, shrinking things, and increasing velocity that way. The other approach utilizes the size and increases velocity by increasing the flow thru the fixed openings. Adding more CFM thru the same size opening also increases velocity, does it not? Well we found that by doing it that way, yields better streetable hi performance than doing it the traditonal way you guys are used to. I've had many discussions about this with engine guys around the country. Some agree, some try to tear that theory apart. All I know is, that by going that route, a very hi peformance motor can be built, while still being very streetable, lower CR, good gas mileage, and lower operating temps. After testing many things, and beating this to death over at CVOHarley.com, many are starting to see this as another valid approach to the 110 engine design. Without going radical, which I certainly didn't want on my touring bike, none over there have acheived my numbers without higher CR's and worse gas mileage. Works for me!

And now I've just started a monster discussion here just tryin to explain it again. But I'd be very interested to see how it's received here as well. Awright lemme have it now!

Hoist!

[uglyDougly]

  I only take offense at the comment about typical response but we need to define the variables then.

  You're saying that there were no engine changes, exhaust changes (including back-pressure), cam changes, cam timing changes, compression ratio changes, inlet or exhaust port changes. The engine was completely re-calibrated for each variable (I would suspect that the top end of the VE tables wouldn't have to be adjusted.)
  Finally, are you talking about differences in low RPM torque at WOT or throttle angles below that?

  Maybe it's time for data?

  Doug

[Hoist!]

  I only take offense at the comment about typical response but we need to define the variables then.

  You're saying that there were no engine changes, exhaust changes (including back-pressure), cam changes, cam timing changes, compression ratio changes, inlet or exhaust port changes. The engine was completely re-calibrated for each variable (I would suspect that the top end of the VE tables wouldn't have to be adjusted.)
  Finally, are you talking about differences in low RPM torque at WOT or throttle angles below that?

  Maybe it's time for data?

  Doug

Hehe!!! Oh no, not all! Everything was modified to get the desired results. Many exhaust tests, much cam and head modelling on the computer by the engine designer, etc. This is by no means a stock HD CVO 110 anymore. I'm not a designer or builder. Just a very passionate owner who wants what he wants, and is willing to be a Guinea Pig if I think it makes sense. A different approach was taken to the traditional modifications with good results. The increase in TQ at low RPM was at both WOT and other TP's as well. We spent hours and hours on the dyno at Joe's Cycle and with Bean at Big Boyz, with both a PC and a SERT. I lost my hard drive last year and all my stuff was gone. But I'll try to scan some the tests done at Joe's which is all I have hard copies of, besides a few final runs from Bean after final SERT tuning. Thanks for your interest on this Doug. Haven't I seen you at CVOHarley too? Same screen name and Avatar for me there. You should be familiar with what I've been playing with over the past 2 years and 2 blown motors!

Hoist!

[uglyDougly]

  I don't have time for two foraa (is that the Latin plural for forum?) so usually I only lurk on others.

  To be clear, are you saying that a whole bunch of stuff was changed to get that low RPM torque increase?
  If that is the case, the throttle change may not have had any part in the torque increase. I would say that the increased throttle size wouldn't hurt or help low RPM torque. That could launch another discussion entirely.
  And yes, everything else is what changes/changed the engines torque characteristics.

  Is that a fair assessment?

  Doug

[geezerglide]

Hey guys,

Since this TB topic is on going I would like to ask a question.

Have an 04 SEEG c/w an SE 103" with some mods, Vortec headwork done by SBC Short Block Charlie), Dave Mackie 590 Cams, Stock TB and injectors, Supertrapp Supermeg 2:1 c/w 25 discs, rest engine stock. Dyno at 103 hp and 116 lb. ft. tq.

I have a Zippers 50 MM TB. As a guess would my performance increase and if so what size injectors should I try?

Doug you may be able to chime in on this as a few year back when I had a Jims 120 you recommended the Kuraykyn 57 MM TM c/e 6.63 injectors and I ended up with 131 hp and 134 tq. Again, Vortec Headwork, that time S&S 625 cams I think and V&H pro Pipe.

thanks to all in advance,

geezerglide

[se]

stock inj will work with your motor just fine .. a read some where that you can also install v-rod inj. i run yelow inj in my 120 and have no issues.

[uglyDougly]

  Yes, the stock injectors will work to just over 115HP. Actually, they will probably go over 120 but the duty cycle is usually above 80% around 115.
  With 0.590" cams the potential is there for over 120HP but that depends on everything else about the build.
  The 50mm TB should help make more HP but if it's a 103HP build, the larger TB won't do squat. (won't hurt either JMO.) If you're over 115HP you should go to larger injectors, which would be, as the previous poster offered, V-rod injectors or the same IWP069 Weber Picos that you used on your 124.

  Doug
 

[uglyDougly]

Hoist;
  Now I get it! You're a contrarian just like myself and a lot of other cranky old farts.

  I really did focus on the 'It's the typical response when I mention this approach to performance mods on CVO 110's.'

  I imagine the typical response is something like; 'it can't make more torque with a larger TB!'

  That's assuming that 'typical' folks think small throttles will create torque.

  I don't agree with that nor do I think that a larger throttle will increase the torque.

  The point I tried, (perhaps clumsily) to make was that the throttle size wasn't the reason for the torque increase, and now that I see what you did, everything else you did to the combination is why it gained low RPM torque. The larger throttle just didn't have any effect on it, good or bad.

  I didn't mean that it can't make more torque with a larger throttle, I meant that it won't make more because of a larger throttle body.

  Doug

 

[Hoist!]

Hoist;
  Now I get it! You're a contrarian just like myself and a lot of other cranky old farts.

  I really did focus on the 'It's the typical response when I mention this approach to performance mods on CVO 110's.'

  I imagine the typical response is something like; 'it can't make more torque with a larger TB!'

  That's assuming that 'typical' folks think small throttles will create torque.

  I don't agree with that nor do I think that a larger throttle will increase the torque.

  The point I tried, (perhaps clumsily) to make was that the throttle size wasn't the reason for the torque increase, and now that I see what you did, everything else you did to the combination is why it gained low RPM torque. The larger throttle just didn't have any effect on it, good or bad.

  I didn't mean that it can't make more torque with a larger throttle, I meant that it won't make more because of a larger throttle body.

  Doug

 

HeHe!!! I knew you'd see it my way Doug!!!

















J/K!!!

Hoist!

[GoFast.....]

Hoist;
  Now I get it! You're a contrarian just like myself and a lot of other cranky old farts.

  I really did focus on the 'It's the typical response when I mention this approach to performance mods on CVO 110's.'

  I imagine the typical response is something like; 'it can't make more torque with a larger TB!'

  That's assuming that 'typical' folks think small throttles will create torque.

  I don't agree with that nor do I think that a larger throttle will increase the torque.

  The point I tried, (perhaps clumsily) to make was that the throttle size wasn't the reason for the torque increase, and now that I see what you did, everything else you did to the combination is why it gained low RPM torque. The larger throttle just didn't have any effect on it, good or bad.

  I didn't mean that it can't make more torque with a larger throttle, I meant that it won't make more because of a larger throttle body.

  Doug

 

HeHe!!! I knew you'd see it my way Doug!!!

















J/K!!!

Hoist!

If the signature at the bottom says Doug, list to the man

[Hoist!]

Hoist;
  Now I get it! You're a contrarian just like myself and a lot of other cranky old farts.

  I really did focus on the 'It's the typical response when I mention this approach to performance mods on CVO 110's.'

  I imagine the typical response is something like; 'it can't make more torque with a larger TB!'

  That's assuming that 'typical' folks think small throttles will create torque.

  I don't agree with that nor do I think that a larger throttle will increase the torque.

  The point I tried, (perhaps clumsily) to make was that the throttle size wasn't the reason for the torque increase, and now that I see what you did, everything else you did to the combination is why it gained low RPM torque. The larger throttle just didn't have any effect on it, good or bad.

  I didn't mean that it can't make more torque with a larger throttle, I meant that it won't make more because of a larger throttle body.

  Doug

 

HeHe!!! I knew you'd see it my way Doug!!!

















J/K!!!

Hoist!

If the signature at the bottom says Doug, list to the man

I listen to EVERYONE and take it all into consideration. And I see he's got his chit together. But ya gotta read the small print too man! It says J/K! Just Kidding!!! Hit the Quote button to read the small print, not find the magnifying glass!!!

Hoist!

[GoFast.....]

Hoist;
  Now I get it! You're a contrarian just like myself and a lot of other cranky old farts.

  I really did focus on the 'It's the typical response when I mention this approach to performance mods on CVO 110's.'

  I imagine the typical response is something like; 'it can't make more torque with a larger TB!'

  That's assuming that 'typical' folks think small throttles will create torque.

  I don't agree with that nor do I think that a larger throttle will increase the torque.

  The point I tried, (perhaps clumsily) to make was that the throttle size wasn't the reason for the torque increase, and now that I see what you did, everything else you did to the combination is why it gained low RPM torque. The larger throttle just didn't have any effect on it, good or bad.

  I didn't mean that it can't make more torque with a larger throttle, I meant that it won't make more because of a larger throttle body.

  Doug

 

HeHe!!! I knew you'd see it my way Doug!!!

















J/K!!!

Hoist!

If the signature at the bottom says Doug, list to the man

I listen to EVERYONE and take it all into consideration. And I see he's got his chit together. But ya gotta read the small print too man! It says J/K! Just Kidding!!! Hit the Quote button to read the small print, not find the magnifying glass!!!

Hoist!

sorry that is small print

[mayor]

gofast, were the flow numbers that you listed in the first post a bare TB attached to the flow bench or were they run through a head?  

[GoFast.....]

Doug, The 107" is finally coming together but got to leave town for a week, I always bolt the TB on to check it right after torquing the heads down to make sure it lines up perfect. One time I put a whole bike together and last thing I put on was the TB and it would not fit because the heads were shaved to much and I to tear it all down after I threw a could of wrenches around the garage. Doug you going to fly to denver and help me dail it in on the Dyno since you know so much about the WT





The 55 HPI Fits perfect. Now take it off a starting putting together the rest of the top end. I like the feeling of knowing what the parts togther did on the flow bench, We will see later if it translates into to power later