numerically higher gear ratio = lower gears
numerically lower gear ratio = higher gears
Our car is geared to go 150mph so it has a numerically lower gear ratio, or high gears. What I am saying is most of us don't need that kind of gearing, so if you put a numercially higher gear ratio in the differential you could have more access to the RPM range. The end result would be a lower top speed and possibly a decreased gas mileage. But you would have more access to the engine's power band.
If you were to put numerically lower gears in the car you would be able to acheive a higher top speed (assuming wind resistance didn't take over), but then your daily power would be greatly reduced. Just remember, lower RPMs does not necessarily mean better gas mileage. All engines have an RPM range that they run most efficiently at. A low RPM can ruin your gas mileage just as bad as a higher RPM.
Originally Posted by WMichaels
Higher numbers = lower gear ratio
The only benefit would be a little quicker launch off the line. I don't know anout the 6 speed but the 5 speed has a pretty low first gear already.
Now you you really mean a Higher gear ratio (lower number), it would be a little sluggish off the line but you would get a little better fuel mileage cruising on the interstate. However your city fuel mileage would suffer.
It all depends on what you're looking to accomplish and what your personal driving habbits are.
In any case... Do whatever it takes to taylor the car for yourself.