Allow me to describe the racer setup for a Daryl Drummond built
bridge ported 12-A of about 244 HP.
The builder with the RX-7 gearbox reduction system was Mr.
Graham in a Varyeasy
I believe.
My racer has a steel button flywheel just enough diameter to mount the
5 1/4" dual disc clutch pack. This mounts over a stock flex plate with the ring
gear TIG welded to the flex plate. The flex plate is just to carry the
ring gear for starting and sees no other loads except for low RPM shaking.
The Rotors are not lightened. The crank is not lightened. The gears in the
trans are straight cut. The engine uses a Weber 48IDF carb and has the usual
Rupp-Rupp-Rupp idle sound.
I set the idle up to 2,200 RPM because clutch management was not the
drivers strong suit.
Also this got him to spend less time in the rock crushing RPM/sound from
the transmission
as the car moved away from stopped.
Like a really big blender full of aircraft bolts. This around 1600 RPM.
Lower with light rotors.
Best power is at 9,400 RPM. Shifting at 9,600 RPM
If you have seen the 45 pound stock flywheel you would know that there is a
problem of some sort. I suggest using a steel aftermarket flywheel to drive
Tracy's torque absorber or similar.
This to further damp the torque pulses and move them up the RPM band away
from idle and ground operation RPM. Start with a steel flywheel or a new flex
plate and check it for cracks
every preflight. The racer still has the original used flex plate, with no
cracks. No driveline damage in 9 years of racing. There are straight cut
gears in the quick change differential as well.
(Move the throttle off of idle slowly. The amount of power in play
while passing through the problem RPM determines the amount of stress
applied).
Lynn E. Hanover