STILLEN and AP Racing have worked closely to develop a new
clutch for the Ford GT supercar. One of the common complaints of
the clutch on the Ford GT is the excessively long pedal travel.
When developing the clutch the Number 1 goal was to reduce this
travel. We also wanted to make the clutch stronger, and be able to
better stand up to higher power output.
One of the fantastic things about the Ford GT is its ability to
perform on and off the track. With that in mind this new clutch was
developed using higher quality materials that will last longer, and
perform better than the factory clutch.
There were four primary improvements made to the clutch that result
in one major improvement.
1. The two AP friction discs have a reduced wave spring in the
middle of the discs. This improves the clutch in a couple of
A) There is a more positive feel to the pedal during engagement
B) The travel is reduced to 65mm (2.55 inches) from 90mm (3.54
inches) from engaged to disengaged. Basically, you won't have to
push so far to the floor to get the clutch to disengage.
2. Clutch cover diaphragm springs are tested and selected to have
the highest possible rating that is still within Ford's range of
allowable tolerances. This is important as an excessively high
spring pressure clutch could cause premature engine thrust bearing
and/or clutch release failure. This also results in a clutch that
is virtually identical to stock in pedal effort.
3. The friction material used is a proprietary AP facing develop
for use in their street clutches. This material has much better
heat dissipation and fade resistance than the factory Ford F510
material used in the stock clutch. The combination of optimized
diaphragm pressures and improved clutch friction material results
in a clutch that can transmit 616 ft. lbs. of torque yet still be
4. The friction discs are upgraded to a 6 spring design rather than
the 4 spring design of the original. This allows for more torque
capacity and increased longevity during heavy use.
This clutch is a direct result of extensive testing done by STILLEN
and Steve Millen on the New Zealand Targa Rally.