Gears for a 2003 GT

Go 4.10s and don't look back

If you use the car primarily for auto-cross then I'd think point-and-shoot acceleration out of the corners is more important to you than highway cruising RPM. I'd suggest 4.10s or 4.30s and consider a differential upgrade to provide more torque bias to help prevent one wheel peels in tight corners.

trinity_gt said:

If you use the car primarily for auto-cross then I'd think point-and-shoot acceleration out of the corners is more important to you than highway cruising RPM. I'd suggest 4.10s or 4.30s and consider a differential upgrade to provide more torque bias to help prevent one wheel peels in tight corners.

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I agree ith this ^^. One thing I would say, use a gear calculator, like this. It will allow you to see what speed you will hit in what gears. Here is an example @ 6000 rpms in 3rd gear with a TR-3650 and 295/35-18 tires.

4.30 = 82.17 mph
4.10 = 86.18 mph
3.73 = 94.73 mph

I know a guy that does a lot of AX. This is how he chose his gears. He went with 3.73s because he was hitting upper 80-low 90s (sc car) in one of the straights. He started with 4.10s and switched to the 3.73s so he would not have to shift. While he lost a little coming out of the corners, he picked up more not having to shift to 4th, then right back down.

I, too, would probably lean toward the 4.10s based on the increased torque multiplication down low. The only disadvantage I see is that they may require more shifts around an Auto-X track. While that is small, it could easily affect times if those shifts are at critical points in a curve, for example.