what do you guys think about underdrive pullies. In one of my previous posts I asked about a squeeling sound. Then someone else asked the same ? and looks like there is a manufacturing flaw. I'm thinking about going ahead and switching to underdrive pullies but don't want to lose any quality from my sound system or accessories. What is your experience with underdrive pullies? THanks in advance.

 

if you are running a decent stereo...don't bother.

i have stock stereo and notice no difference in voltage, but with the added draw of amps and speakers you probably will.

the gain isn't much anyway. just kindda one of those "bolt ons" for those of us who can't dig into a full heads/cam setup

 

ok, thakn you, I will keep stock

 

It defintely improves throttle responce and adds some power...alot of LS1 guys like em...I would reccomend asp

 

You can always under drive the crank and overdrive the alternator. = same charging.

 

geez now I'm confused. Is underdriving/overdriving changing a pulley or a balancer or what? How much would that cost in parts?

 

Tha ASP pulley is lighter than the stock unit as well. The motor will spin up quicker. I like mine.

 

and underdrive pulley is smaller than stock which will spin the accessories slower, this requires less energy (hp) to do...therefore giving back some lost horsepower to the engine.

the ASP pulley for the LS1 is a pulley/harmonic balancer combined. pullies for the old l98 or lt1 were piggyback...meaniing they had the stock balancer in place with the pulley between it and the engine.

to overdrive means the pulley is bigger, which will spin it faster. therefore since the underdrive pulley on the crank spins everything 30% slower (arbitrary number) the alternator spins that much LESS. now if you put a BIGGER pulley on the alternator...it will counteract the underdrive of the crank pulley.

this means the alt will spin at or near stock speed...reducing the chance of power loss from the alternator not spinning so fast. but all the other accessories will still be going slower, freeing up hp.

i know the ASP pulley is about $230 i'm not sure how much an overdrive pulley is for the LS1. that would take some shopping and research.

 

www.tpis.com makes an underdrive crank pulley with an overdrive alternator pulley to keep the alternator charging coorectly. somone out there has to make the same thing for the LS1. i looked for a link but didnt find one yet. if i do i will post it.

david

 

sorry that above reference is for the LT1. doesnt help your LS1 much.

 

www.thunderracing.com

49-540120 ASP Overdrive Alternator Pulley, 1998-2002 LS1 F-body (Special Expires 11/05/2004) $22.99
Sale! $21.84


49-948500 ASP Harmonic Balancer Crank Pulley, SFI 18.1 Approved, 1998-2002 LS1 F-body (Special Expires 11/05/2004) $214.99
Sale! $204.24

 

you'll want to look at the 2 pulley sets. One is for the crank, and one is for the alternator. Dont' think they cost any more than single pulley sets.

 

Thank you guys for the info. Now for the real ? is it worth it? Think I'll see much of a gain? Current mods:

Long tube Headers
Corsa Exhaust w/cutout
Heads/cam -on order
3600 stall Tq Converter
3.73 rear gears
Whisper Lid
Granatelli MAF
some other suspension stuff.

 

I noticed a difference with mine. The motor seems to rev quicker with the underdrive. I think it's definately worth it.

 

The alternator issue has obviously been discussed previously in this post. Would installing an underdrive pulley affect the AC, water pump, or power steering? Would the expected life of said components be shorter as a result of the installation? Thanks!