[ba] Re: [s-cars] 80tq Update: 516 wheel hp, 450 wheel TQ
JShadzi at aol.com
JShadzi at aol.com
Thu Mar 3 11:56:12 EST 2005
Hap, thanks for the observations! See inserted:
>First of all, thank you for your painstaking data logging as you've gone
>along on this project. As I compare some of my altitude compensated dyno graphs,
>there are some striking differences. With both your current T-61 and the HO
>hybrid graphs, your torque figures are significantly lower than your horsepower
>values. In my case, lets talk round numbers so we don't get into any altitude
>conversion gobledygook(very technical engineering jargon), my torque values
>exceed the horsepower significantly. This produces a nice looking double hump
>graph that provides a very streetable car.
Absolutely, what cams are you running? I'm currently running both 7A cams, I believe the RS2 exh cam with stock AAN intake cam produces much more power down low due to the lack of overlap, the 7A's introduce some overlap but breathe noticeablly better on the top end.
One thing I've considered is to take the current setup and only change the cams to the AAN cams to see what happens to the power curve, I may do that as another data point for whomever considering cam choices.
>I realize that streetability is not what you were about here, but I think
>there is an avenue that you can improve upon that would provide more down low
>power. I'm talking about your charge air system from your compressor outlet
>through the head. I've done a lot of work on my charge air plumbing and I think
>that's where I get my more robust torque curve. As these large compressor turbos
>are trying to spool up, any blockage in the charge air path will hinder the
>spool. Once they're up to speed, there's not much that is going to get in the
>way of their power. I've had a lot of work done to my FMIC to enhance its flow
>characteristics. I also had a lot of work done to my intake manifold i.e.
>drilled, ported, enlarged. My throttle body had a Big Bore mod done to it. I know
>you've had your head ported and so have I but if the restriction is on the way
>there, its not going to matter.
Yes, I agree, there are huge areas of improvement to be had, I've purposely not upgraded the IM and TB just to push the pieces as far as they'd go, I estimate quite a bit more power to be had by opening these up. The goal has been to push some known components as far as they'll go to see what the limits really are. I have been surprised, however, that top end power has remained very linear as it should. With the .63AR turbo I began to see some power drop towards redline leading me to believe the AR was restricting breathing, by keeping the turbine and going with a larager .82AR, top end power was again restored, with no induction changes.
Eventually we'll uncork this baby completely and see what she can really do =)
>You probably remember that I had a similar fueling issue when I had my car
>out there a little over a year ago. My solution was a fuel reservoir, for the
>stock pump to feed, 044 Bosch pump, larger fuel lines, and larger injectors.
Absolutely, I will run 2 pumps in parallel, I estimate this will solve the pressure problem.
>Anyway, I just thought I'd share some. Regardless, keep up the great work. I
>should be mounting my tubular manifold and GT 35R shortly. I had a .63 AR GT
>30R hot side machined to fit my 35R so the results should be very interesting.
>Oh yeah, I polished the compressor;-) Gotta be worth something!
Yes, very nice turbo, that should get you to 500whp if everything is optimized, I will look forward to hearing about your results!
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