My friend has a 88 vette with a pretty much stock rebuilt L-98 350 tpi engine.

He recently bought trick flow heads 195cc(?) CNC chamber, 1.6 roller rockers and is going with a hi flow exhaust system with full length headers.

Stock head flow ( chevy hi perf.)

http://chevyhiperformance.com/techarticles/p104408_image_small.jpg (http://www.chevyhiperformance.com/techarticles/41598_cylinder_head_flow_bench_database/photo_08.html)

Trick flow

I dont have flow data for these heads but I believe they are approx. 240's/180 @ .600


He knows the tpi set up is restrictive.
A few guys from his vette club says he wont gain any performance because of the tpi.

He's worried he waisted his money for nothing, but I cant believe he wont see any gains.

Any thoughts?

He may even see a decrease in performance :( Those TPI motors are really matched for there specific purpose. Don't get me wrong, I love my old TPI 85 T/A but it's almost better to leave it alone or plan on stepping up to the bigger TPI boxes and intakes.

Bill

He's also gonna upgrade the chip/computer.

plan on stepping up to the bigger TPI boxes and intakes.Bill

Where can he get more info. on these?

He can try thirdgen.org; but sifting through teh monkey-spank is getting pretty tough these days. Too many of those guys talk too much about "planning", "going to do", "read it in [insert magazine or web site here]", etc. Pplus, the few people who had actually figured out how to work WITH it instead of AGAINST it, have mostly moved on to more modern projects with far more potential.

Bottom line is, TPI is a system that was CAREFULLY matched from the factory, to do ONE SPECIFIC THING. It does it pretty well. For the time that it was introduced, it was the hottest setup on 4 wheels. Problem is, within 3 years, it was hopelessly obsolete. Hasn't gotten any better in the 20-odd years since. And since the basic principles of physics that it relies on haven't changed either, it's just as hard now to improve on it, as it was in 1987.

The exhaust will speed his car up, IF the appropriate programming is done, to give it more fuel. The heads will slow it down, especially with a stock cam and stock programming. Only way around that, is to "de-tune" the "T"PI feature, and make more use of raw flow and less use of the "tuned" aspect of "T"PI. Which will decrease the "Mt Everest" torque peak that TPI gives at 3600 RPM, but could possibly make the car faster by improving higher-RPM HP.

He found someone to burn a new chip for his application.

Maybe one of these hi flow intakes will help.

http://static.summitracing.com/global/images/prod/large/edl-3891_w.jpg

If those are from SLP, they have really good stuff.

Bill

The performance forum in the C4 section at www.corvetteforum.com has some experienced TPI users. You may want to check there.

Just get a set of Accel runners, port the stock base. Get a cam in there with 220 @.050 duration or less, (a good tune, and I dont mean a lousy Hypertech ship either), a stall of 2400 and hold on. He may be able to get by with 22 lb injectors...If they are the stock Multecs throw them in the trash where they beling and get a set of Bosch (22 or 24 lbers). I think a 180 head would be best but anythings better than the stock heads, they dont breathe for squat.
I got a corr. 13.9 out of my old 89 Vette. Couple of free mods, did some cleanup work on the intake and upgraded the Y pipes to 2.5" with cheapie high flow cats. Not bad for 125k miles and still knocked down 17/24 mpg.

Fwiw, try to get the runners used and work the stocker over. Spending a grand or so for a bolt on aftermarket intake will get you a whopping 12 hp if youre lucky. Serious.

Thanks for the info guys.
I'll pass it along.