[swamp2]

To the above two posts:

I'll try to offer some further explanation.

You can either try to understand this deep or technically or just on the surface. Sure a FD multiplies torque to the rear wheels. It does it with a constant percentage and across the speed/rpm range. OK more torque to the wheels does matter. It is a key ingredient of acceleration and performance but it obviously is not the entire ingredient list. If a FD mod gave you more torque at the wheels with ABSOLUTELY no drawbacks:

1. It would be essentially magic, making any and all cars faster.
2. All OEMs would be using new/revised FD ratios
3. There would be some sort of regression to the absurd with infinite FD ratios. And if traction was not an issue you would get ever increasing acceleration.

The last point is key, you can't simply keep bumping and bumping the ratio. And just thinking very "on the surface" - there is no such thing as a free lunch. A transmission mod does affect your engine itself and obviously does not give you more hp. hp is THE most important factor (well hp to the wheels per weight, but whatever, that is just a detail).

How long you can hold each gear is the other absolutely critical ingredient of the performance equation. You do notice how much harder your call pulls in 1st compared to 2nd and in 2nd compared to 3rd, etc.? How the FD hurts you is that you get less time in each gear. Get it?

Now again if you only consider in gear results you will certainly feel that increased torque to the wheels and you'll think it has improved everything.

Again "success" the mod itself (with regards to actual measured results) will depend on how well the OEM optimized the FD. In some cars a FD mod might get you a small bit of improved performance all around. But in most cases you'll get improved in gear results and a variety of effects when measuring specs where multiple gears are used; some slightly positive, some slightly negative and some will show no change.