Has anyone done a dyno comparison back-to-back between the different pulley reduction options?

 

15<16<17<19...

 

true true...

i guess just wondering how much hp it (17 or 19) gives in comparison to, say, less "warranty-voiding" mods

 

Now, I'm not trying to start a war, but I was under the impression that the 19% had the same power of a 15% but a little more torque. I bought a 19% and about had Randy Webb install it, but after his teaching lesson, I went with the 15%. He mentioned that if you're looking at a curve that starts off low, rises, peaks, then starts to drop off, the 19% (or anything aove a 15% pulley) is on the backside of that curve. Apparently, the 15% is at the peak of being efficient.

Trust me, I've read every post on here about the 19% and about went that route, but it just doesn't seem like a logical way to go just to get a few more ft./lbs. of torque.

I wish someone would dyno this stuff and get this debating crap out of the way. It's all hear-say until it's proven. I could even be way off base by believing the 15% is the same as the 19% in power, but after hearing Randy talk, he's very well educated on this subject and has done enough research to back up his claims.

 

All due respect to Randy, he told me that the Schrick "race" cam would have less torque than the "street" (which they discontinued)... I was told the same thing by others......I finally ignored them and put it in......guess what... torque improved across the entire power band.... I had a 15 % and went to 19%.... unless you are tracking the car and never below 5K rpm the 19% far out performs the 15 % (at least in my car)..... Randy by his own admission is a track guy and the high RPMs that he lives at do all the bad things he talks about....but for street driving and "spirited" Dragon style runs...I prefer the 19%.....NJMO.......

 

I'd like to see not only dyno plots of torque vs. rpm, but also IAT vs. rpm, knock vs. rpm and timing vs. rpm for each of these. Preferably if the dynos were run on the same car on the same dyno in the same atmospheric conditions as well as running the same gas, etc., etc.

 

great idea but you have to monitor the EGT and the IAT as well as the temps from the IC etc.....I have learned the hard way that air charge temp is critical to these cars....... so just swapping parts without regard to all the other variables would not give you the info you want...just some numbers......(I know you know this but maybe some new folks don't)

 

Sorry to post off subject, I don't have dyno's for all pulleys.

But there's something here that I can't really figure out. I've met Mr. Webb and he is a smart man, both mechanical and buisness wise. I've head the story about haveing a smaller pulley than 15% personally. What I don't undertand is why he installs a 15% sc with a 2% crank pulley all day long and has negative comments on that set-up. Maybe somone can explain it to me. -- Johan

 

Good luck with that and good luck not getting criticized for stating the obvious.

 

The problem is Money...it costs money and time to dyno......start a fund and pay someone to do it....$10 from a lot of people gets the job done...no..wait..we tried that with intakes.....still a lot of problems......Oh well..... good luck

 

SpiderX is right--not about the money, since all evidence on NAM suggests we all have way too much money--but about the inability of any set of dyno tests to prove anything without error or doubt. It would be an incredible pain to do controlled dyno tests of 3 or 5 different pulleys, as they'd have to be put on the same car, and other environmental factors would have to be controlled for.
Of course, this reminds me of the speaker cable wars I once fought in, where people formed up along a line, with "there's little to no difference, it's all in your head (butt dyno" at one end, and the pencil and paper theorists at the other end arguing about rpms, densities, efficiencies and the like.
If you are a butt dyno person, then use that to make decisions. If you're like me and listen to Randy Webb whenever I get the chance, but make up my own mind, then stick with a 15%.
In the end, I think it's all a little trivial compared to other, more significant mods that can be made to a MCS (having fallen into the tires, wheels, brakes and suspension crowd finally.)

cheers,

 

Gandini - Have you had you car on the dyno yet? Your setup is pretty much what I want to get mine to one day...

 

Scroll up to the top and click on radio and listen to the latest White Roof Radio podcast.

 

Yes, some time ago, but with most engine mods present. It made 180WHP, which is over 200 crank HP, which seemed reasonable compared to a new JCW for example.
I'd like more power, but I think the handling mods have given me more bang for the buck (still, there's been a lot of those spent in that department.)
I think a DFIC might be next, but I just ordered an M7 STB, just to finish off the suspension mods.

cheers,

 

I did about 50 HP runs to get repeatable data on 5 different IC configurations....

Matt

 

hmm well lets see. with Progression of my car, Ive done several Dyno runs with different set ups at different times. Started Stock portable Dyno at VMP 145 whp. Next on a stationary DynaJet. 15% with Super trapps and lw wheels 167 whp. Folowed by MTH standard file ( there was no tuner at this time) 178 whp. Next mod 19% pulley JCW injector and JCW programming 192 whp. Next added 2% crank pulley Larger tires and Heavier wheels. did a Pull in Virginia Beach believe was also a DynaJet 194whp. Did a pull today using Cam 2 race gas still with the larger tires and Heavier wheels same set up as VB pull on a Mustang 1750 DE . did 206whp. If interested my Race wheels and tires are 13lbs per rim and tire lighter than what i ran and also approx 2 inches Smaller. Which translates to approx 10whp difference on a dyno. I do have the 17% pulley as well but never ran it. All runs where done at the entered Weight of 2750 lbs. and in the same gear. ..

I also have a few more Mods coming up in the near future (head and Header) that should unlock a few more ponies. Currently all internals are stock and Drive line changes including LW Flywheel , GTT intake, Flywheel and super trapp exhaust were present for all runs except stock. The Dynajet runs except the VB run was done at the same Dyno with approx 72 degree weather. VB run it was colder but the Mustang was also at 72 degrees.

Hope this info helps some. I know it will be talked about and argued since different conditions were present at each run. but it does give the general idea of how they differ.

 

Yes, getting good data can be a pain and sometimes an incredible pain. Would you rather get data points that in no way relate to each other, just for the sake of having data points?

 

I sure hope that you put some mileage on the engine between each of those mods/pulls that way the ECU gets to adapt to the new configuration.