the thing with pulley's.. dont install em right and your screwed.

With an intake, or exhaust, dont install em right you get to redo it. Thats where the risk comes in.

Pulley's themselves arent really rocket science fella's.

I wouldnt even compare these to FI. The risk is much much less. With Pulley's your not changing really anythinga bout the engine except for how much inertia is lost/used to turn it.

With intakes, exhausts, tunes, etc etc your changing the dynamics of how the car works internally. FI takes that to a different level altogether. If anything pulley's should be one of the lowest risk items. Unfortunately it attaches to a place where a wrong install could be bad.

You can compare a pulley system to a lightweight fly wheel. Good stuff unless again installed wrong.

This is why NST puts a Steel ring around the inner part of the pulley. To prevent the aluminum from welding itself in and providing a proper bearing.

Well... ok... yeah... but it's the undampened vibrations that ultimately cause fusion and extra wear and tear on the crank.

I think the real debate is whether or not a V6 is "naturally balanced" enough to not be overly concerned, and I think it's unknown at best, especially considering our motors rev pretty high, and high revs will greatly exacerbate the effects of undampenend harmonics.

Just sayin'...

On the other hand, aren't our cranks forged? I suppose it could be sturdy enough to withstand the extra vibrations, but again, it's not clear.

As to the FI compariosn, I just meant that I'd rather risk the motor's longevity for a 100+ whp increase in power than a 5-6 whp increase...

Really the light+underdrive pulley is more about throttle response than rwhp. Adding a few horses from underdriving is just a bonus. Also, if there were any harmonics issue, it doesn't increase linearly with RPM, making it worse the higher you rev. It would be at a specific RPM (or more than one specific RPM) that exhibited bad harmonics for the crank without a damper.

I had the Stillen UD pulley, it was installed wrong and within a day there was oil leakage. Next day I had the stocker reinstalled and the crank oil seal replaced, no issues since. I'm done with aftermarket pulleys now. I did get a lightweight flywheel however that I will be getting installed, I believe this will be better way to increase rev speed without the same potential risk.

Just out of curiosity, how are people getting these installed "wrong"? Seems like a pretty straight-forward job.

AFAIK they didn't get it torqued on well enough/properly, so it had some wobble that caused the issue.

That's correct, the purpose of my purchase was to improve throttle response.

My NST pulley needed to be filed a tiny bit for it to fit properly. I'm sure something would've broke if he forced it in without filing it down.

I'm assuming these have a woodruff key? Most common way to screw it up is to catch the key and push it out of the groove. You're pretty much blind on any install like that-you just have to hope it didn't happen.

On my kart clutch, it's keyed and I see a lot of people push the key out when installing a new clutch. Then the clutch jumps the key and a few seconds @ 16,000 RPM and your crank is toast.

IIRC (it's been a while since I installed mine), our crankshaft pulleys just use a straight key (as in, a notch along the inner side of the pulley, and a "key" that stands out from the side of the crankshaft near the end).

I've ordered the stillen lightweight pulleys and not the under drive ones..the same issue applies?:confused:

installation issues can apply to anyone installing the pulleys even if they were replacing the OEM pulley with another OEM pulley.

so its basically depends on the installer themselves? i mean if the get it right or did it wrong..

pretty much.

thanks for your help Dai! repped!:tiphat::tup: