borlavette

I have a 01 c5 6spd with full exhaust and varraram intake and tune I had rpm rebuild my tranny due to 2nd gear grind. I also had them put 390 gears in and a new rxt racing clutch and MGw short throw shifter I don't know if I made a good move by switching the gears it doesn't feel faster I thought the 390 will feel quicker any body else do this?

GARY2004Z06

It should both feel and run quicker. I recommend 4.10s; however, 3.90s will provide nearly the same results. A gear change is perhaps one of the best mods.

borlavette

Did you do this mod also? Is it only good for 1/4 mile or for roll racing also?

GARY2004Z06

As stated above, we go with 4.10s in our stick setups. It was used in both the C5Z and C6Z with favorable results. The greatest advantage is from a dig. Roll race outcomes can be determined by rpm range, trans ratios, and maximizing power under the curve .

Gxpz06

I went went from 323 to 373s in mustang and Yes felt quicker --YET if you are doing highway pulls in Roll it may not seemer quicker...

with that said Im going to try first time shorter gear on the c5z for first time to run the World cup All motor event and I hope it Goes QUicker

then its 3.42 back on for Nitrous runs

Op is that you have different Trans Gearing then you had before ? for instance could have gone from a 2.97 1st to a 2.66

Glensgages

. . . for-what-it's-worth . . .

in 1981, I began making changes to my then-OEM 1979 Z28 that I had bought brand new in 1978:
changing carburetor, intake, heads, cam, ignition, and shift-kit for the automatic 3-speed transmission resulted in the 1/4-mile performance dropping from 16.4 @ 82 MPH to 14.4 @ 97 MPH, shifting at 5500 RPM, but trapping at just 4500 RPM with the stock 3.42 gears

a swap to 4.11 gears, with no-other changes, instantly resulted in 14-teens @ the same 97 MPH, but I was then hitting the stripe at 5400 RPM

currently, although my 2003 Z51 A4 coupe came with 3.15 gears, I am contemplating going to a 3.90:1 or 4.10:1 ratio

SPEED750

Watching this one ! This mod is on my list. What is your difference in rpm on the highway?

C5 Pete

My suggestion for the C5 is;

Auto trans, no more than 3.73 if your car is primarily a street car.

Manual trans, 4.10.

Have owned both auto and manual C5s with multiple different gear sets in each in primarily street driven to primarily race driven.