What size is the smallest supercharger pulley you can put on a 1999 grand prix gtp without having to modify anything else?

Answer 1

When modding a GTP and changing the supercharged pulley, you will want to go with a 3.4" pulley. If you do this, however, you will want some supporting mods to reduce knock retard in the engine, which retards your ignition timing and reduces the power output of the engine. Supporting mods for a 3.4" pulley would be a K&N cone intake, which you can make yourself, colder spark plugs, a 180 degree thermostat, and a little exhaust work would help, also. Just a u-bend removal and a 3" downpipe would work.

Answer 2You really need to plan out your modding strategy. If you just start throwing parts on your car chances are you're going to be in for some real headaches.

Knock is very detrimental to these engines. You need a scanning tool to find where your engine is at the moment before modding. Then check afterwards, you may need additional modding in order to keep your motor from blowing up, even from just a small change in pulley size. There are many people that have gone down this road. Learn from their mistakes and do it the right way from the begining.

Check the write up on pulley size at:

http://www.clubgp.com/newforum/TM.asp?m=2867792&p=1&mpage=1&tmode=1&smode=1&key=&language=

Hope this helps

"G"

ANSWER FROM oogpgtp

I went with a 3.4 pully swap on my 2000 gtp but first I added a cat back 3in exhaust, k&n cold air intake, MSD ignition coils and wires, and most importantly a transmission cooler to keep the heat down. These mods cost about $ 1300 and really woke my beast up. To change the pully you'll need a proper pully tool. I bought a gm tool off eBay for about $100.