Underdrive Pulleys

**GottaHaveLS1** · 10-30-2005, 05:49 AM

Has anyone installed underdrive pulleys on an LS1 and noticed a decent gain of power. Could anyone tell me what i would need to do to install a smaller pulley?

**ninobrn99** · 10-30-2005, 06:24 AM

i cant say that i noticed power by the SOTP but the revs are much much better over stock!!

**GottaHaveLS1** · 10-30-2005, 08:13 AM

Was it difficult to install them? What tools did you need and how long did it take you?

**ninobrn99** · 10-30-2005, 09:11 AM

i think ive got it down to about 20-30 minutes if i dont stop and everything goes smoothly

Id get a longer bolt from napa (i did) and it makes it go so smoothly!! The craftsman pulley puller 46909 or something like that is the one you need! it works awsome..only thing is the damn bolts that hold the arms together fall out sometimes which could cause some delay. pm me or just post up if you have any questions. Here's what i recommend:
remove the belts with a 3/8" 15mm socket
remove the harness off the fans ( need a flat head and the front end needs to come up) then remove the fans. this is so you have room for the puller and the ratchet.
screw the new bolt in just before it gets hand tight. place the puller on make sure the arms are on the notches on the inside of the pulley, tighten slowly till the pulley starts to come off. after you see its coming off, you can go faster. Put a little bit of oil on the new pulley and just press it onto the crank. use your old bolt to tighten it down till it wont turn anymore, remove the old one and replace with a new crank bolt and tighten it tight

if you have a stick, make sure its in 4th and the ebrake is on good! an auto you can either get a flywheel tool or get someone to hold it with a screwdriver to keep the motor from turning over.
Nino

**GottaHaveLS1** · 10-30-2005, 11:21 AM

That seems pretty helpful. Thanks. By any chance does anyone know a site with a procedure and pictures?

**ninobrn99** · 10-30-2005, 11:33 AM

thats all you need to do. I used to have a link, but i think i deleted it. Its really simple. What are you confused about? I know the install very very well so I can answer your questions if you need help.

**MadSeason** · 11-01-2005, 03:38 AM

20-30 mins nino, shit it takes me that long just to jack the car up sometimes. As for the mod, I have a M6 and no complaints here, faster revs and an increase on highway mpg's.

**ninobrn99** · 11-01-2005, 07:05 AM

not much to it.
pull the air lid and maf
take the belts off
break the bolt loose
replace with longer one
get a jack on the side or front of the car, lift, thorw a jackstand under it
set puller on pulley
remove
replace in reverse order..not much to it see

**SeVeReDiStOrTiOn** · 11-01-2005, 09:54 AM

I've learned that it's never as easy as it sounds...and something always goes wrong

**ninobrn99** · 11-01-2005, 10:02 AM

true, but sometimes things go right

ive been too damn lazy to pull my fans and pulley. When i get back home in Nov. Im removing them both w/o jacking up the car...shouldnt be difficult. just a pain in the back!