notsue

Just wondering whats up with the crank pulley and why theres a smaller one thats actually being used.

BIGCAT7274

It's a under drive pulley.

wrd1972

iTrader: (12)

^ yep.

notsue

Thank you, that was my guess, but I didnt realize people did that with these... I keep finding new things on this car everyday...

R3DLT1

iTrader: (5)

ha ur just hitting the very tip of the ice berg

bufmatmuslepants

iTrader: (3)

Take off the big pulley there is no use for it anymore, just adding rotational mass. I have the same thing but I dont get why the hell someone left the stock pully on the outside...

notsue

Anyone know why it has two belt grooves?

the impaler

The underdrive pulley has no harmonic dampener built into it like the stock pulley does. Removing the stock pulley is a bad idea

tt383lt1

iTrader: (3)

^^ yep

notsue

I will more than likely just return it to stock. I'm not really that interested in whatever minor gains I may be getting from it.

3DFORMULA

iTrader: (4)

thats not a bad idea but it's not hurting anything I don't believe

notsue

Sometimes when I'm at idle, my volt meter shows pretty low... and if I have my blinker on it blinks really slow... figured this might have something to do with the alternator. When I'm driving it reads normal, and its not low everytime at idle, but I had been wondering what would make it low ever...

tt383lt1

iTrader: (3)

i would pull the under drive pulley off and put it back to stock if it was my car

notsue

I have plans to remove the intake and clean it, when I get around to that, I'll go head and remove the under drive pulley and replace it with the stock one. I also plan on taking care of that leaky timing cover, I already feel I know whats causing it... I found an air foil in the TB and removed that, I'm waiting on a new elbow because mine is covered in silicone and still has visible holes... slowly taking her apart and cleaning her up to see what she does by herself... if things are good then heads and cam here I come If things dont look good, then we'll build a motor on the side and put it in when this thing goes.

bufmatmuslepants

iTrader: (3)

Take off the stock pulley, Ive run a lightweight aluminum underdrive pulley for the past 4 years and not had a single problem, and I spin my motor to 6100 rpm. Ditch the stocker, use the underdrive, it revs noticeably faster without that giant hunk of metal hanging off the front.

SS RRR

iTrader: (2)

It has everything to do with the U/D pulley. Your battery will be dead w/in a few months if that keeps up. Only way to run a U/D pulley and not kill the battery is never drive in stop/go conditions or run and overdrive pulley on the alternator.

tt383lt1

iTrader: (3)

did you buy the elbo already. i have a nice one im not using

bufmatmuslepants

iTrader: (3)

Dude this is totally false. Like I said, Ive been running a small underdrive pulley and never changed my alternator pulley and I have NEVER EVER EVER had a problem. Your battery is not going to ******* die. Take off the damn stock pulley and run just the underdrive, and it will be FINE.

wrd1972

iTrader: (12)

I have to respectfully disagree with this. The stock dampener is vital for the long term reliability of the engine but more specifically, the crankshaft by helping to absorb the normal fatiguing resonance that occurs each time a cylinder fires. These resonance might start to degrade the crankshaft over time as well as the main bearings under certain conditions.

This is a vital part for engine longevity because GM spent X amount of dollars to put it on the engine. If it were really not needed, it would not have come on the engine from GM.

I suggest that the OP keep it as is or simply remove the piggyback pulley and use the OEM piece. If he is still wanting to reduce mass and still have the functionality of the crank dampener, then look into the ASP underdrive dampener which is much lighter than stock and much cleaner in appearance.

Above all I think there are very little gains to be had by using either type of underdrive pulley or dampener.

SS RRR

iTrader: (2)

Interesting. Mine ******* died six months after putting the pulley on. When the U/D pulley was first introduced there were all kinds of complaints from people of their batteries ******* dying. March did not make an O/D pulley, until they started receiving complaints about batteries ******* dying.
It does depend on your driving habits. If you drive in stop/go conditions where there is not enough voltage to properly charge the battery then the battery is going to eventually ******* die. M6 cars did not have a battery ******* dying problem as much as the autos had a battery ******* dying problem.