Underdrive pully can cause problem if the crankshaft is long(such as I-6). It breaks harmonic balance in engine causing added stress on crankshaft

But in I-4 or rotary engine it shouldnt be a problem.

 

Ok, so the balance issue makes some sense. Although I would think that if you are worried about balance then I wouldnt change that pulley at all. Even a lightened pully is going to change it.

This the case couldnt we change the other pulley on all the accessories? This would give us the same result without changing the balance on the engine. Best of both worlds.

Aaron

 

Rick stopped selling the lightweight pulleys,which were originally made by emc2. I believe the reasoning was there wasn't enough demand.

 

That's funny there wasn't enough demand.

Lightened flywheel, clutch, and ancillary engine accessories are the next place to free usable HP once you do the typical bolt-ons.

 

Aluminum crank pulley for S2000.