VHR + FD Gear Ratio upgrades - 3.9 and 4.08

Z1Performance

the 4.08 is without question the one to get. It's a big enough step up from the factory 3.7 that it will provide a noticeable change in acceleration, but without putting the car into some crazy rpm zone on the highway in 6th

Here is how it shakes out vs the stock 3.692 final drive. Tire used for these calculations is the 275/35/19 found in the sport package, and the factory 7500 red line. This is top speed per gear, based strictly on ratios. Obviously wind drag has a huge effect, but for purposes of this discussion it is not taken into account

Stock 3.692
1st Gear 42.36MPH
2nd Gear 69.15MPH
3rd Gear 98.95MPH
4th Gear 126.44MPH
5th Gear 160.7MPH
6th Gear 202.39MPH


4.08
1st Gear 38.33MPH
2nd Gear 62.57MPH
3rd Gear 89.54MPH
4th Gear 114.41MPH
5th Gear 145.42MPH
6th Gear 183.15MPH

As you can see, acceleration per gear will be ~10% quicker per gear, and top speed is reduced by ~10% per gear