08 and up 103 build with your hands tied (Stock pistons, OEM dbw TB with mods)

[1FSTRK]

maybe this will help vic.
this is a 2008 stock t/b 255 cams SE kompressor heads 10.5 pistons. V&H true duals. cranked 225 ccp.
shows you what kind of peak tq you can get with stock heads T/B  and compression .
heck all he has to do is pick a cam ,and build a pipe 

This was not about helping Vic or proving him wrong. He was straight forward with his estimates and so far everything in this thread has shown to support them.

I understand that jacking the compression with either an early cam, higher static comp ratio, or both will make early tq but the motor will also nose over and lack in the hp department as your graph shows.

I understand that 1.2 hp/ci is not uncommon for a well-designed 103 kit that includes the right cams and head work as well as a bigger TB and pistons.

The throttle body question is hard to word so that you get useful answers; there are already plenty of general threads on throttle body size. I know someone will post up a healthy 124ci with a factory DBW TB and show they made 120hp through it, it is my opinion that they gave up 10 or more hp because of the stock TB. It also does not mean that you can bolt that same stock TB on an equally healthy 103ci and make 120hp. I think the 124ci motor will create more vacuum than the 103ci because it is a bigger pump and just like being on a flow bench and flowing the same TB at two different pressures you will get less air through it on a 103ci motor.

Here is where I think the pistons come in; the compression limit will dictate the cam choices which will dictate how much head work, which will tie back in to how much the TB should flow. This is why I did not ask about what cam and specific head work.

So far I have learn that there are a couple places that rework the factory DBW TBs and that the 2008-2010 can go to 54mm but the 2011-2013 TBs are limited to about 51mm because of their outside dimensions.

Are all the 2014-2015 touring bikes coming with a 50mm TB that can be reworked larger to say 54mm much like the 2008-2010?

Looking over the graphs posted so far it looks like the air flow is capping the HP in the 110-low teens with the usual difference of the builds with the slightly higher tq making the slightly lower hp and vice versa within 1-2 points
There is some good info here, thanks to all that have contributed so far.

[strokerjlk]

Sorry I though the idea of the thread was to see where the constraints were .
I though Vic wanted some info on the stock FBW setups .
I wasn't trying to prove him wrong on anything . I was trying to help him .
If I had know it he didn't want help , I would have never posted .

[1FSTRK]

Sorry I though the idea of the thread was to see where the constraints were .
I though Vic wanted some info on the stock FBW setups .
I wasn't trying to prove him wrong on anything . I was trying to help him .
If I had know it he didn't want help , I would have never posted .

Jim no problem here, this thread was just me doing some digging. I have never owned a DBW bike and so I have paid little attention to what goes through Vic's shop unless they are big CI big HP builds that catch my eye. None of this had to do with him, not even sure he has seen the thread.

I try to stay up on this stuff and I guess that I fell down a bit on the DBW TB end. I have been spoiled because even with my 110ci he just bored and worked the stock cable drive TB and it was enough. I have guys I ride with that I have probably given the wrong advice when I told them to just have their stock 2011 TB reworked not knowing that they had a DBW that can only go 51mm with work.

I am just trying to take what I know about motors and add some understanding of what these stock DBW TBs mean to it all as far as what point the limits change. As I looked at things It seem to me that once you change either the TB or the pistons you might as well do both and get a full package build that is north of 1.2 hp/ci and by the time you do both it looks like another $1000-$1250 depending on the products used.

Looks like some basic head work, cams, will put you in the 110/110 range at this point so why spend more than basic money unless you go all the way?

[strokerjlk]

Ok guess I misunderstood . Vic had asked me about 103 potential .
I saw your thread and though it was related .

Don't discount the stock heads making 115-116 tq . And with the right exhaust/ cam / compression it should do 100-105 hp . The 103 / 255 / 225 ccp 103 ,showed me that long before Durwood's stock head 103 made 115 tq .

[1FSTRK]

Ok guess I misunderstood . Vic had asked me about 103 potential .
I saw your thread and though it was related .

Don't discount the stock heads making 115-116 tq . And with the right exhaust/ cam / compression it should do 100-105 hp . The 103 / 255 / 225 ccp 103 ,showed me that long before Durwood's stock head 103 made 115 tq .

Those are kind of a different build. As I said the early tq can be made without flow, early IVC and compression will get it done. Those builds are one reason that I ask for graphs just a tq number hit at a single rpm does not mean much to me if you give up too much performance everywhere else.

[strokerjlk]

Potential . That graph has taught me a lot .

[Don D]

That early torque will come and be optimized with a 1.85 intake valve and cam such as the tman 555tq or tw57h at 10:1

[1FSTRK]

Potential . That graph has taught me a lot .

Yep Potential gets talked about a lot that is why I ask for graphs and build specs.
Please be specific, what has it taught you to help with this build, what will it take to change that graph to equal hp and still have stock pistons and a OEM DBW tb

dvsracing and oldhippie both posted sheets that are using the two constraints in the OP with the shape curve we are looking for. My question was and is without changing the shape of the tq curve or moving it right or left how high up can it be raised with the use of the OEM pistons and DBW TB and what parts does it take to do it.





Basicly 100tq or more in by or before 2500 and flat, peak hp before 6000

[1FSTRK]

That early torque will come and be optimized with a 1.85 intake valve and cam such as the tman 555tq or tw57h at 10:1

The OP question was how much HP/TQ so what is the answer if you used the above parts?

[strokerjlk]

If a set of stock heads produced 116 tq , then a set of ported heads should do the same .
Testing the right exhaust and cams , is the hard part .
That's why I said , all you have to do is pick the right cam and exhaust .

[1FSTRK]

If a set of stock heads produced 116 tq , then a set of ported heads should do the same .
Testing the right exhaust and cams , is the hard part .
That's why I said , all you have to do is pick the right cam and exhaust .

Here is where I respectfully disagree with you the big elephant in the room is how much HP can you get through the DBW TB with a 103 sucking on it. If we use your 116tq number now can we get enough air through the TB and enough cam to make 116 hp without losing the bottom end because the bigger cam dropped the running compression and we still have stock pistons?

[m1marty]

Im using a pretty conservative cam set at a streetable compression and making that. Not a max effort build by any means....Id think I could pick up a few more on both going with a larger cam and a .027 gasket. Like I said before tho- injectors are pretty close to max on mine.

[TorQuePimp]

That early torque will come and be optimized with a 1.85 intake valve and cam such as the tman 555tq or tw57h at 10:1

  I agree with this and I do not see the stock pistons as being that big a power constraint.

  The 2011-2015 FBW throttle bodies are pretty much the same and there are places they lightened them up and thinned them you just cannot take metal where you need to.

  If that is all a guy has and is not willing to buy a HPI/S&S/SE you do the best you can with what you have

[1FSTRK]

Im using a pretty conservative cam set at a streetable compression and making that. Not a max effort build by any means....Id think I could pick up a few more on both going with a larger cam and a .027 gasket. Like I said before tho- injectors are pretty close to max on mine.

I would have no problem with going to bigger injectors if needed.
What pipe do you run?
I think the graph for your bike had the tq crossing 100 lbs at 2750-2800 any way to get that below 2500?
Was that the best graph and was it SAE corrected?

[1FSTRK]

That early torque will come and be optimized with a 1.85 intake valve and cam such as the tman 555tq or tw57h at 10:1

  I agree with this and I do not see the stock pistons as being that big a power constraint.

  The 2011-2015 FBW throttle bodies are pretty much the same and there are places they lightened them up and thinned them you just cannot take metal where you need to.

  If that is all a guy has and is not willing to buy a HPI/S&S/SE you do the best you can with what you have

John I am fine with that on the TB I am just asking to see what people post as "the best you can with what you have" when we stay with these two oem parts.

As for the two cams listed what is the most power with them at the available compression when coupled to the aforementioned TB?

Added:
You and Don have those two cams listed, M1marty is running Don's stuff with 10.75cr, TR-577 cams and had the Fueling cam in it before and just said he thinks the cam needs to be bigger for an all out effort build.

[strokerjlk]

2009 103 stock DBW T/B larrys stage 2 heads .HQ 575 cams shitty exhaust

[strokerjlk]

2010 FLH SE 103ci BB  stock heads, ported local . stock T/B stock head pipe 259 cams

[strokerjlk]

same heads diff cam exhaust as the one above. stock 07 cable T/B
251 cams open pipes

[strokerjlk]

this is a 103 stage 4 dealer build.10.5 pistons Harley wegner exchange heads thunder header 2010 super glide stock T/B, stock clutch

[strokerjlk]

this guy did his own heads. he is friends with AlanB. when Alans stage 2 2012 flhx went 100 hp. Bob decided to use a 57 cam also and do his own heads.
he used the same headpipe as alan . but he stuck with the v&h mufflers.
power dual head pipe. stock T/B. I felt like it would have went 4-5 more hp with crushers, like Alan's.
friends have to be diff  
its a 2010 limited stock pistons and t/b

[strokerjlk]

2010 FLHX 103 Ward heads 10.5 pistons 662-2 cams rb racing 2-1 Stock T/B

[strokerjlk]

You Sure you don't want to see some 106-`107's 

[1FSTRK]

Thanks but no.
We want 103 builds not removing cylinders or pistons

[m1marty]

So what is it exactly that youre after? The highest you can push a stock piston/tb 103? The largest amount of tq at the lowest rpm? As posted earlier- Aharp hit damn near 120 squared within the parameters you set. Mine is 115/115 consistently with a couple few *hero runs* showing better. Tq crosses 100 right at 2600 and thats fine for me. I dont ride in that area. 2800 or more is the range I stay in. I like my stuff to carry to the right. Im using a Dragula with a 2.55 baffle.

[1FSTRK]

So what is it exactly that youre after? The highest you can push a stock piston/tb 103? The largest amount of tq at the lowest rpm? As posted earlier- Aharp hit damn near 120 squared within the parameters you set. Mine is 115/115 consistently with a couple few *hero runs* showing better. Tq crosses 100 right at 2600 and thats fine for me. I dont ride in that area. 2800 or more is the range I stay in. I like my stuff to carry to the right. Im using a Dragula with a 2.55 baffle.

One of the hardest things on a forum is to keep things technical and not personal. I am not putting down any build or information posted, I am looking for information and I was specific in the OP on what info I was after. You have not posted your graph, although you have described it, I would love to see Aharp's graph but it was lost from the dyno section so we do not have that. I do not make judgement on how you ride and I am glad you are happy with your tq, I hope you do not hold it against me for wanting tq that comes in earlier.

In the OP I specified that the throttle body and pistons (therefore compression) would be what limited this build, there are a number of posts telling me that statement is not correct. There are plenty of high compression big throttle body 103's out there over 115/115 and yet in trying to only post builds with OEM DBW TB's and stock pistons there is not one graph posted here making over 115hp/115tq. 

Thank you for sharing the information on your build. It may turn out that the limit for this is such that you are right there in the top on the class, I do not know that is why I have been asking.