Compared to the AP1, the
AP2 generation of S2000s were cushier and more street friendly for the general
American consumer. A larger engine and shorter gears gave more torque at the
wheels, which Americans desired. But, Honda also matched a heavier flywheel and
modified the clutch system, negatively impacting its track worthiness. Step two
of phase two of Project 82000 will shift the drivetrain bias towards the track
side of the equation, compromising a bit of everyday drive ability for better
performance.
A larger engine and shorter gears gave more torque at the wheels, which
Americans desired.
A weak spot of the AP2
drive train is the stock clutch -the engine doesn't exactly make a lot of
torque. The other weakness is the clutch release delay valve integrated into
the slave cylinder. When the 82000 first came out (APl1generation), it became
an instant favorite on the autocross stock class circuit. The car must be
mostly stock, but it can run high-grip R compound tires. Launching by dropping
the clutch off the 9,000 rpm rev limiter destroyed many differentials.
Honda got smart (like
Mitsubishi with the 2005 Eva) and installed a clutch release delay valve so it
didn't allow the clutch to be dropped, thus reducing the shock on the
drivetrain. Mitsubishi did a lot of warranty work on 2003 Eva clutches after
owners were launching their cars with redline clutch drops. On the 2005 model
year, they introduced the clutch delay valve along with a 5,000 rpm neutral
limiter. Anyway, back to the S2000.
They introduced the clutch delay valve along with a 5,000 rpm neutral limiter.
On the racetrack, the
weaker clutch combined with the release delay valve can cause clutch slip
during fast shifts in high gears. I noticed this during a track day at
Button willow where it slipped a few times on the three-to-four shift. Once on
the four-to-five shift, the clutch slipped completely and the engine rpm shot
to red line. I had to back off the throttle completely to allow the clutch to
grab.
If you decide to get rid of the delay valve, you can either modify your AP2
slave cylinder or just use an AP1 slave cylinder.
My solution to this issue
was to upgrade to a Centerforce Dual Friction clutch. I left the delay valve in
as it can make moving from a stop on hills easier. If you decide to get rid of
the delay valve, you can either modify your AP2 slave cylinder or just use an
AP1 slave cylinder.
