I was just wondering what would give a better power increase with pulleys...Would stock size lightweight crank give better power than underdrive or vice versa? I tried a search, but the only info I really found was arguments over whether the underdrive would be bad for the engine after a while...which seemed to be based on opinion for both sides...

depends which is lighter and the torque required to move it a certain angular distance.

so, almost always an underdrive would provide more power.

So hypothetically if the underdrive were the same weight as the stock size lightweight pulley, the underdrive produce more?

well, yes. this is becuase most of the weight is more centered(or should be) on an underdrive pulley than on a stock pulley.

not by much though.

How about a lighter Underdrive pulley :nudge-nudge: :wink-wink:

Wasn't there talk about doing something like this? There was somebody up in Toronto that was doing something for us.

Click Here

My car will be coming off the road shortly, I may be able to donate all pulleys.

REDZMAN can we contact this guy??

almost all the lightweight crank pulleys out there that i know of are underdrive.

^ Yeah, good point.

I pm'd that Nick Boers guy to see what happened with the Pulley deal. I'm up for helping. I wouldn't mind a set either as well.

Hopefully he checks in.

There are no standard size crank pulleys out there as they are all underdriven. Power pulleys (PS, Water) yes. Not Crank.

Underdriving accounts for only 25% of the gain. The rest comes from the weight savings.

From my readings, I seriously doubt a pulley set is going to yield much power. The only benefit is an easier revving engine and maybe an mpg increase. That's about it.

Don't expect 8HP like their manufacturers claim.

i think some of the power pulley sets are actually overdrive pulleys. the overdrive should make up for any accesory power lost by putting an underdrive crank pulley on.

Well, I'm not really expecting an 8hp gain, i was astonished that it was listed at that to be honest...I would've thought 8 hp max if you have a heavily modded engine haha but I'm not expecting that, just smoother acceleration and easier revving...and I'm pretty sure you're right tibby01 about the overdrive, because the OBX package on e-bay says overdrive pulleys on it...too bad one of the pulleys doesn't fit haha.