3.90 and 4.22 gear set up

[Tim_C.]

Wow! that looks very good to me.

So what do you think of the gears on the track? Improvement, the same, worse, etc...?

 

[firearrow13]

StarquestRescue -- Do you still have the 4.22 gears available to sell?

[StarquestRescue]

Old thread, but i never really wrapped it up.

The short answer is my car was no quicker at the track with either the 3.90 or the 4.22.

 

It did pick up trap mph a little. I will say it was easier to get a good et with the slow spooling turbo i had then. Now that i have a different turbo and more power i have no problem getting out of the lights or pulling the stock 3.54 to the top of my power band.

 

The lsd re stack worked great at the track. I could really tell the difference during the burn out. It did chatter a little on the street.

 

I sold the 3.90 to a guy with a auto car and he was quite happy with it. I started another 3.90 build but never finished it. Maybe i will have it done in the spring.

 

The 3.90 worked best with my mt et street slicks, 26" tire. At the time i had stock size street tires and the extra rpm got old. Balance shafts would have made a big difference. If i would have had 255/50's for the street it would have been better. It was also real easy to spin and over rev on the street if i got on it in first gear.

 

For some trans swaps like the say the t-56, gears would be mandatory. Or say a 4g car with a higher power band and less torque would probably like the gears.

[Tim_C.]

Yeah, with the 3.90's, at first I felt like even a stock engine would benefit, but now after driving more, I think they really need an engine built for a little higher power band. I would say forged pistons and shaved rods are a must, and enough flow to not give up at 4500 like the stock cam and smaller turbo combinations do.

 

I don't have track results, but mine with the 3.90's is a great set-up. I can drive on the highway no problem with a higher average RPM because the engine is built for it.

 

Yes, we all seem to agree that even a stock automatic set up would benefit from the 3.90's. I have an auto car that I hope to put my other set of 3.90's in eventually.

 

The beefier stack sure helped on mine too, but does act like a lock up in parking lot turns.

 

Oh, and I agree about the tire size too. 255/50's are a good size for a manual 3.90 car. That puts the overall ratio a lot nicer for street driving, especially with an engine with a relatively stock power band.