i have a 91 camaro z28 5.7 tpi with the stock 3.23 gears. I want to gain ACCELERATION! but i still want to be able to go on the freeway at decent RPMs.

if i got 3.42 im worried that it wouldnt be worth the expense. but if i go with the 3.73 im worried about the freeway.

anyone have any experience with either?

 

What's ur rpm at highway speed now with the 3.23s?

 

i got 3.42's in my 85 roc at 80 mph my rpm's are 2500

 

my rpms at 70 is about 2200

 

so at 70 with new gears you would be turning

3.42 ~ 2330

3.73 ~ 2540

 

M/T ET Street Radials
2800-3000 stall torque converter.
TransGo shift kit
100 shot of nitrous

Those will make any TPI car accelerate like a champ.

I had 3.73's in a tpi setup and I felt like it was too much. First gear was dead and over with REALLY fast and I wasn't even past the 60ft clocks at the track.. I think 3.23 is ok with a 700R4 and 26" tires.

I'd go 3.42 if I HAD to choose but in this case I'd stay 3.23.

 

Stay with the gears you have. 3.23/3.27s are perfect for TPI. And I agree with AutoRoc, a good stall will be your best mod. '

If you really want to get gears, especially 3.73s, you will need some TPI intake modifying. Or just convert an LT1 intake and be done with it. But if you are like me, TPi is here to stay, there are thing$ you can do to make it breathe better.

 

I run 3.42's, and would jump at a deal on the 3.73's - used to run 4.10's in my LT1 Caprice- which, obviously, weighed a lot more- I doubt you would even notice the difference going from 3.23 to 3.42-

So, running 2500 ROM's at 70 is a bad thing? You are just getting into the meaty part of the power band- and how many stop signs and traffic lights do you leave per day? That is where you will really notice better gears-

A stall would be good, too- watch out for more heat, though- probably should upgrade the tranny cooler if you decide to go that route-

 

im mot saying its a bad thing, i just think 3rd drags out to long. and i what im looking for is to lower my 1/4 mile time. i ran 13.9 with just a cat back. but since then i have pit in these mods-
-true ram air
-MSD cap, rotor, coil, wires plugs,
-adj fuel pressure regulator
-ported plenum
-air foil
-jet sage 2 chip
-high flow cats
-exhuast cut out
-rebuilt tranny
-stage 2 shift kt.

im looking for 12's, and im hoping gears would help me. but i still want to be able race on the highway.

 

Get a real tune for starters.

 

Add a 3k stall to that list as well as some headers.

 

13.90 with the mods listed is better than I ever did with a TPI setup, good job.

If you're wanting a highway race car, you're starting with the wrong combo. TPI engines are best suited for stump pulling/towing rather than highway racing. It has a very short useable powerband that is all washed up by 5000rpm. 3rd gear drags on too long because it needs more power.

 

i ran the 13.9 at 101mph on my stock 5.7 with JUST a cat back exhaust and ram air. idk what i will run now after the mods.

but how do i get a "GOOD TUNE"?

 

Im not sure if i want to get a stall, because i want to drive my car on the street without it getting irritating.

 

AutoRoc-
I LOVE your Z, its bad as hell!!!!!