Originally Posted by SimAwd
Why not a 4.11 final drive for auto-X?
Does an sti 6 spd be better for highway, gas millage?
the sti 6th gear has about the same ratio as the wrx 5th, its just that the gears in between are closer together to keep the rpms in the power band.
i just plugged the numbers into a gear ratio calculator:
The 2.2L 4.1 rear diff with a .78 5th gear will cruise at 3100rpms at 75mph.
The svx 3.545 rear end with a .78 5th gear will cruise at 2800rpms at 75mph.
Going from the .78 5th gear from the 2.2 to the .738 5th gear from the wrx only saves you 150rpm at 75mph.