Unorthodox Underdrive Pulleys

Michael Jez
Mon, 6 Jan 2003 23:21:13 -0600

Bzzzzt WRONG. SR20 is internally balanced piece of beauty, U can remove the
flywheel and all the pullies and run it like that. The crank is balanced
from the factory, unlike Detroit iron- domestics. So U can run UD pulleys
and have no problems. The UD pulleys also prevent water pump cavitation on
higher RPMs. Its not a whole lot of help, but every little bit helps. I have
beat my NA SR20 with 200 some K miles on it to hell on a race track in
Phoenix with constant 6-8K RPM and I didn't overheat once. Gauge sayed where
it was supposed to be- I have no AC in my car - removed since I don't use
it. I have had my pulleys for like 2 years now, and they are great. No oil
leaks or anything. I went from 146WHP to 159WHP with a set of UD pulleys,
JUN flywheel and JWT ECU. They work fine and after installing these 3 all at
once U can feel a MAYOR power increase throughout the powerband. I have
never put any cams in my SE-R but I feel it would be in the 168ish range
with some S4 JWTs. Engine was freshly rebuild by me.
Mike Jez
93 SE-R GTi-R powered now- build up by me too :)-- got broken into tonite !
01 Max with fixed Cattman Ypipe- bling bling.

> You should be aware that the
> UR crank pulley removes the harmonic balancer. The harmonic balancer is
> there for torsional vibration in the crank (unlike balance shafts). The
> crankshaft actually twists back and forth as the engine runs and the
> balancer damps it. This vibration can beat the hell out of your bearings
> if severe can cause crank failure.