TW26 vrs Mackie 630...

[tireater]

I switched from an And 37 to a WT26 in my St Bob...Not real impressed with the gains...+3/2 1/2...
I have been hearing good things about the Mackie 630..The dyno guy says it will wake this bike up...Thoughts..?

[NightTrain67]

.....or make it a total dog.  What are the specifics of your build?  If you don't have enough compression,the 630 Mackie will kill it.

[tireater]

103", Hal's speed shop 04 pro st heads shaved .050 w comp. rel. and grooves, jims forged race stroker C.S. welded...
Weisco forged flattops, o deck, com. .030 HG, WT 26 cams, 10.4 CR, ThunderTrapp exhaust and Ness BS2...

[Arrowsmit]

I have chronic CRS, but it seems like I recall reading that the WT26 needs something a little different done w/the exhaust ports/valves to work to potential? Maybe some of the Kury-cam guys will chime in here...

VicW.

[Showdog75]

 I'll get blasted for saying this but the heads don't need anything special on the exhaust it's mainly the intake that needs attention . If any of you guys ever read anything that Doug Lofgren posted on the old htt you should remember that he said most harleys are over exhausted when it comes to cams and head work .

[Showdog75]

 UglyDougly1 Sent: 10/18/2007 9:31 AM
If a head porter had a blank shhet of music what would be the ideal flow / intake to exhaust ratio to shoot for to optimize let's say the WT TC26

  Wow, that's a big question.
Keep in mind that everything in this answer is my opinion, so I won't apologize for every sentence. You can accept my apology for respon ding to the original question. In fact, I think this an interesting thread, more shoild go like this.

First, any cyl. head should be ported with an eye toward low lift flows on the exhaust and high lift flows on the inlet.
One characteristic of a port is the seat ID/valve dia. ratio. 86% is pretty good for an exhaust and 90% is good for an inlet.
The first thing that will accomplish is higher ex/in ratios at low lifts than at high lifts. Which brings up the question; at what lift do 'they' say the ex/in ratio shouldn't be greater than 70%? ('They' being the American V-8 guys.)
If the ports are optimized, the ex/in flow will largely represent the valve size ratio. The ex/in valve size ratio of a Twim-Cam is greater than most V-8s so you should see ex/in flow ratios larger than 70%, then most H-D head guys put larger exhaust valves in (along with larger inlets) which increase the low lift ex flows even more because the seat radius get larger.
Correct so far?
If you have high ex/in flow ratios that should mean that you need less cam on the exhaust than you would if you had low ex/in ratios.
If you run at lower RPMs you should need less exhaust flow/duration/valve size because exhaust requirements are profoundly influenced by RPM.
The single pattern cams are supplied to the H-D community by the Chevy cam grinders and those cams are designed for 8000 RPM roundy-round racers with school bus cylinder heads (low ex/in flow ratios.) These cams came into use in the good-old-days before CNC cam grinding, so the cam grinders just slapped an inlet lobe on the exhaust and that's how it has been since. You don't need best high lift flows on the exhaust side so you don't even need the same L/D ratio (lift-to-diameter ratio) much less the same absolute lift.
The latest 15,000 RPM liter bikes use similar L/Ds on the exhaust as the inlets so they have lower exhaust lift than inlet and they have 90% + ex/inlet ratios.
If you're running a 6500 RPM engine with high ex/in ratios you need less exhaust flow or valve size or duration relative to the inlet.
And, one more thing. The steady-state flow values of a racing V-8 don't show/represent the extra volumetric efficiency you get from a 13" tuned inlet over the H-Ds 'Y'manifold design. The steady state flow values of an H-D should then be much lower than 70% if you want to use single pattern cams.

After optimizing the ports of a Twin-cam, and considering the RPM range that it will run, I didn't see any cams that were suitable. They all had too much exhaust.
There is no benefit from running more cam (exhaust or inlet) than you need. It makes tuning more difficult, and it looses torque at every point below the peak HP RPM.
After approaching the power of the TC4G with the TC2G we decided to increase the lift of the inlet and leave the exhaust alone.
That is how the TC26G came about. Make the most with the least!

I had tuned Bob's Road King witha TC3Gwhich had a little less inlet lift and a little more exhaust lift and duration and the 'Crusher' kit (makes me think of 'Crusher' Kowalski the wrestler) and we also put a prototype 54mm throttle body on it, and I couldn't get more than 116HP from it.
Then Bob assembled the shop '05 Dyna with the TC26G and it hit 123 at the end of the tuning session.

And yet one more thing. Everyone talks about the engines gaining HP with break-in. Most builders insist on break-in before tuning. Bob Wright and Mike Roland were religious about that. My reasoning was that the tuning process is the ideal break-in because you heat cycle the engine while you set up the TB and idle mixture, then you add load as you adjust the calibration to an ideal AFR.
Soon Mike believed me and we tuned every one of the test bikes right off Bob's lift.
What I've found is that they only loose power. I've checked several of the builds (the shop Dyna in particlular) and they don't make the same power as when they were fresh.
Smokey Unick insist that Pro-Stock engines run the best with a haze of carbon on the piston tops and the tuning process gets that done.
Put a set of heads on the flow-bench with carbon all over the valve and seats and see how they flow compared to when they were squeeky clean.
Since most folks don't dyno a fresh engine, they can't compare.

   Doug

[ejk_dyna]

 <<I'll get blasted for saying this but the heads don't need anything special on the exhaust it's mainly the intake that needs attention .>>

no you are both saying the same thing.  the exhaust does need to be done differently than say for an s&s cam or even woods to get maximum performance with wt.  it does not mean more...just different.

[ejk_dyna]

the mackie 630 would be a disaster for your build.  your build needs a 58 intake close and 262 duration like a hole in the head.

[NightTrain67]

the mackie 630 would be a disaster for your build.  your build needs a 58 intake close and 262 duration like a hole in the head.

I agree 100%.  10.5:1 compression plus a Mackie 630 would be a train wreck.

[Showdog75]

Some more food for thought
Sent: 10/16/2007 1:38 PM
  I have what is possibly the most extensive collection of Ducati Desmoquattro cam profiles on my Cam Prop Plus software. The Desmoquattro is the older 4-valve that was raced until '98
  What I learned from that or rather what it confirmed is that inlet and exhaust have very different requirements.
  On the inlet side an increase in RPM will net more air into the engine. Of course, the ports can let you down as the airflow goes up, but basically, the pistons displaces/evacuates volume faster and the engine airflow trends upward.
  The exhaust is required to empty a large percentage of the hot gas between E.V.O. (exhaust valve opening) and BDC. ('They' say 50% of the exhaust volume needs to be eliminated by BDC.) That condition is low lift and high pressure. That implies that exhaust flow has to be most efficient at lower lifts.
  At max pistons speed ( approx. 70 BTC) the pressure is low, the temp is high, the density is low and piston pumping has little effect. High lift exhaust flow is not too important. Plus, with ports, the compromise is good low lift flows will loose high lift flows. If you want one or the other you'll want good low lift on the exhaust.
  Finally, at TDC, where there is virtually no piston movement, you need glld low lift flow for the exhaust and inlet tuning to remove the last of the residual exhaust gases and start the inlet flow.
  What this boils down to is that exhaust is very sensitive to time (RPM) while inlet is not so much.
  A high RPM engine needs longer exhaust duration than a low RPM engine. The Ducati superbikes used the same long duration exhaust cam from 1991, when they made 140HP at 11,5000 to 1999 when they made 175HP at 12,800.
  The exhaust valves got larger but the lift didn't. The duration was more than they needed in 1991 at 145 and enough in '99 at 175.

  Next, the H-D cams are offered by manufacturers of Chevy/Ford/Chrysler performance cams.
  The Chevy engines have smaller exhaust-to-inlet ratios than Harley's and lower exhaust-to-inlet flows relative to the H-D heads, as well as working on higher RPM engines than the H-Ds.
  The automotive (read Chevy racing) world says exhaust-to-inlet flow shouldn't be greater than 70%. What are the ex-to-in flows of most H-D heads, and at what lifts?
  All of those factors implied (to me) that more ex lift and duration aren't necessary. The benefit of less exhaust duration and wider lobe centers is lower overlap. I think that the power numbers we achieved with the Wild Things cams (no matter what you think of the power/torque curves) confirm that more overlap isn't needed to make those numbers. Less overlap just makes tuning easier and light load running smoother and more efficient.
  The direction we went was toward finding the least cam to accomplish the most performance, and I learned a lot about cams and engines.
  Mike Roland has always been a leader and not a follower and I'm not a Harley guy, so between us we were able to break the cultural barriers and try something different. For that, we got different results, not the same old stuff.

  Hope this sheds some light.

  Doug

[GoFast.....]

<<I'll get blasted for saying this but the heads don't need anything special on the exhaust it's mainly the intake that needs attention .>>

no you are both saying the same thing.  the exhaust does need to be done differently than say for an s&s cam or even woods to get maximum performance with wt.  it does not mean more...just different.

Elk, I have to diagree because that is not what Mike Roland will tell you who created the cam

[sean fxd]

Boy reading those posts from UglyDougly and looking at the radical differences in cam timing between the wt26g and say s&s585g I would sure think that porting requirements would be different like EJK says.  So you are saying that Mike Roland says they should be ported exactly the same?

Sean

[Don D]

Very differant, but easily obtainable.

[sean fxd]

Deweys-that makes perfect sense to me but Gofast response to ELK seems to say the opposite.

I must be missing something...as usual...LOL

Sean

[GoFast.....]

Deweys-that makes perfect sense to me but Gofast response to ELK seems to say the opposite.

I must be missing something...as usual...LOL

Sean

Sean Elk is saying they do not need to be diffrent and I saying they do need to be diffrent. One is you use a bigger exhaust value and two you want more flow on the low end. Then you put more compression in it.  showdogs was at 10.82 and he says he does not use the compression releases, I put that much in my sons bike at 5800 ft and went down to Sturgis which is a 2000 foot drop and still did not use the compression releases when it was cold. Must of been running something like 210 to 215 ccp down there. The valves showdog used were also what I used 1.90 in, 1.625 ex. Here I pasted Mikes 52  old htt dyno post on it. He has more detail on his build

http://groups.msn.com/Harleytechtalk/dynoruns.msnw?action=get_message&mview=0&ID_Message=1073573&LastModified=4675695149950692889

             lift      duration     open    close
Intake.    575    248            18        50

Exhaust  495     242            48        14

You look at a cam like this and say how in the world can a cam with low of lift which makes the valve train sound almost stock make 120hp in the right setup

Well 248 duration is not a small cam but the lift on the exhaust is so crazy low. The answer is you have to compress lots of air through the heads and you have to do it by .495 lift on the exhaust side. Bob Wright that ports heads for this cam has it down but others can build heads for it by putting in bigger exhaust valves and getting more flow on the exhaust side down low, Hope this helps

[skyhook]

gofast,
you're confused about static compression...it doesn't change with elevation...CCP changes with elevation...otherwise I understood the same thing about the head porting requirements of wt cams

[GoFast.....]

gofast,
you're confused about static compression...it doesn't change with elevation...CCP changes with elevation...otherwise I understood the same thing about the head porting requirements of wt cams

thanks let me correct that

[GoFast.....]

I switched from an And 37 to a WT26 in my St Bob...Not real impressed with the gains...+3/2 1/2...
I have been hearing good things about the Mackie 630..The dyno guy says it will wake this bike up...Thoughts..?

Hey, tire eater, If you take the wt26 out let me know. I will buy them from you if the price is right

[mayor]

tireater, I think your looking in the wrong dog box for your lost hound.     Changing the cams for the third time won't get you better numbers if their not what's holding you back.  My advice, step back and look at what you have now.  Your first build with tw37's only hit mid 90's HP in a 103", you raised the compression and changed cams which only gained you 3 more HP.  Based on dyno's from all over the country, the 37's are capable of hitting mid 90's and up in 95"ers when coupled with good heads.  Furthermore, the WT-26 cams have proved to be a reliable performer when set up properly as well based on results from some of our own HTTer's. 

[tireater]

I'm thinking the problem is the stock throttle body...I need to check the CCP today...and check for sumping...
It seems possible the rings didn't seat right...There was some smoke on the dyno...(it could of been the tire)...

[grnrock]

get a different tuner.That build is fine I think there's more.
Grnrock
Formally fvecamBill

[hogmandon]

was wondering what your numbers were with the 37s if they are chains I will buy them if $ are right

[tireater]

I got 94/105 with the And 37 in my 103"...Make me an offer ...