i was wandering how much my 273s and a open diff. is holding me back.
the best 60' i've been able to cut was a 2.28 times were 14.6@95mph but that was before the h/c and 1.6s. what do you guys think i would run now and how much would i gain if i had a posi and some 410s?

 

might knock off half a sec go 410's with a manual and 373 with a4

 

I don't konw an exact amount of gain but i would definalty got with a posi and some gears

 

let you know in a week or 2. i have 2.73's now. scheduled to go with 3.73's next week. ill head to the track after that. then i will be getting a better tc.

best time for me so far on 2.73's is 13.1 @111mph, 2.04 60'

 

I'd almost bet my paycheck that "Engineermike" has the fastest 2.73:1 LT1 car in the states. He's ran really quick on his stock, limited-slip 10 bolt. Maybe he will chime in.

Ben T.

 

Chiming in. . .

Gears are way over-rated, especially if you have an engine with alot of low-end torque, like the LT1.

sw89lt1, you'd do alot better if you invest that money in a decent muffler to replace that BlowMaster. I gained 40 rwhp on an old 310 rwhp combination just by replacing a FlowDisaster with an SLP straight-through muffler.

I've found that a good torque-converter has a much greater effect on quarter mile than gears. I'm not talking about one under $600 either. . . We changed the gears in my friend's '99 T/A from 3.73's to 3.23's and the quarter mile did not change one bit, but he had a 7 pump Vigilante (3600 rpm) converter.

As for my combo, the turbo 383 makes truly prodigous torque, especially when applied through a 0 pump Vigilante (2800) which flashes closer to 5200 rpm at 19 psi boost. It works quite well with the 2.73's, thank you. Plus, the tall gear makes the non-OD TH-350 quite liveable on the interstate.

You should, however, consider upgrading to a posi.

Mike

 

forgot to add i'm running a 5 speed.

 

Sorry . . . I guess I assumed you had the "correct" transmission for drag racing.

 

i went 13.01 with 2.73 intake exhaust and a stall. I just ordered a set of 3.73s to help with the cam

 

By the way, I haven't been to the track yet with the new turbo setup and 2.73's. However, my old supercharged combo went 10.40 at 133 on the 7.5" rear end with 3.42's. With 130 more rwhp, the car feels way faster now, plus the torque is just stupid. Have no doubt that the car will run 9.7 - 10.0 at 140 - 142 mph.

 

What's with the diss of Flowmasters? I've never had a problem with them and I know plenty of people with them.......

 

Two guys that are local to me are running 2.73 10 bolts with their built & stalled 4L60s. One is running very very low 12s (he has stock heads too), the other is around mid 11s. These are both LS1 F-cars though

 

Dude, where have you been??? Like I said, I've gained 40 rwhp in back-to-back dyno testing by getting rid of a Flowmaster. Other locals have had similar results. I though everyone knew they suck.

 

That's not the impression I get from people I know, and even people I don't know.

Maybe you should make a sticky thread up in this forum so everyone that has Flowmasters knows to take them off.

Maybe you lost 40 rwhp because of something else in your setup? I'm sure not everyone with Flowmasters is losing 40 hp. Everyone's car is different.

 

We didn't change anything else in the setup. The car also went from consistent 12.80's at 110 to consistent 12.30's at 114 mph. Exhaust backpressure went from 9 psi down to 6 psi.

Admittedly, the more overlap you have in the camshaft, the more sensitive it will be to exhaust backpressure. So, if you have a stock cam, the Flowmaster won't hurt you as much as a larger aftermarket cam. My combo was an 8.5/1 355 with the GM 847 cam (234/242), so it had a fair amount of overlap and didn't like the 9 psi backpressure at all.

Would you believe that we've seen equally terrible results from Spintech mufflers? It's funny how the people who like Spintech and Flowmaster never did any back-to-back dyno testing. They just go by impressions and opinions.

This has been discussed in various threads many times before. I've also posted before that my last 550 rwhp supercharged combo only gained 5 rwhp by removing a 3" Hooker Aerochamber. Ever since that test, I highly recommend Aerochamber mufflers and use a 3.5" on my current turbo combo.

Mike