When it was time to test drive the car, all we could say was wow! The OS Giken made such a big difference that the entire MotoIQ staff had to go and try the car out. The diff went a long way toward eliminating torque steer and steering wheel fight. You could apply full throttle on corner exits, and the car would just want to accelerate and rocket out of the turn.
You could get on the gas before the apex even, and the car would tuck even tighter into the turn, accelerating through the apex with no understeer at all. Everyone was ranting that the OS Giken diff was so good, they would consider getting an FWD car if the diff were available for it!
Sitting at a corner, getting ready to do a right-hand turn, you could just dump the clutch and turn right hard while flooring it, and the diff would accelerate the car rapidly away with little wheelspin. When doing a drag launch, the car would rocket off the line with little wheel fight.
When we first installed the diff, it did rachet slightly and occasionally would make a clunking noise, like any clutch type LSD diff. However, after a few hundred miles of use, it broke in and became very smooth. You could hardly tell a clutch type diff was in the car unless you got a little silly.
We can wait to see what the OS Giken will do on the track with sticky tires and more power! Right now we feel that this is by far the best FWD differential, and front of an AWD limited slip differential, there is bar none. We already felt that the OS Giken was the best RWD LSD out there!
Adding the lightweight Centerforce aluminum flywheel was a great improvement as well. Even with its feathery 7.1 lb weight, it was still very smooth and streetable. It did not require more slipping of the clutch to get underway and was very driveable in bumper to bumper traffic. A lot of this also hard to do with the silky smooth Centerforce Dual Friction clutch being very streetable.
The flywheel made a pretty big difference in acceleration and shifting speed. It also made heel and toe rev matching much easier. In fact, the revs claimed so quickly with the new flywheel that we found ourselves over blipping the gas for a few minutes until we got used to the fast response.
All in all, we were very happy with this round of mods, and we felt what we did made such a huge difference that a very good car is being transformed into something really special. And, we haven’t even touched the engine yet!