I am a mechanic and recently bought a gtp. I finally got it running and looking good but stock. I want to do a pully swap first. Does anyone know how small of a pully I could go down to on a stock tune?
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08-24-2011
I am a mechanic and recently bought a gtp. I finally got it running and looking good but stock. I want to do a pully swap first. Does anyone know how small of a pully I could go down to on a stock tune?
08-24-2011
Stock with no mods do not just drop a pulley size. Your car will hate you and possibly go boom.
Please read this...
http://www.grandprixforums.net/safel...car-17482.html
08-24-2011
Pulley size can go first if the 2nd mod you want to do is a new bottom end.
Don't do it.
Let the car breathe before bringing more air in.
Simple concept.
Read the thread Rynoman posted that I typed up, and welcome to the site!
08-24-2011
Welcome
08-24-2011
Welcome.
More air coming in with less air going out = more boost... In theory...
Originally Posted by W-Body Store
08-24-2011
Well I hear all different stories from when I was in college. I had a friend that droped a pulley size and blew it up, but then this chick I worked with droped to a 3.4 on a stock tune and it was fine. So i figured for now I could go with a 3.5 or 3.4 pulley on a stock tune. The pcm will figure out that theres more boost and add more air and fuel. Well you guys seem to know whats up, how about a tuned pcm, 3.4 pulley and a catback to start?
08-24-2011
Imo, don't do the pulley drop till you do the supporting mods. Custom intake, and headers/downpipe are where I'd start. Then do the pulley drop and tune at the same time. If you can find someone local who tunes with HP tuners, go that route, a custom tune will always be better than a preprogrammed pcm.
08-24-2011
Listening to these ppl do not drop pulleys yet do not
08-25-2011
Skip the catback, they don't benefit you until some crazy hp number... I think it was 400whp or something.
To go with a 3.4 on a gen 3 I would do headers (Speed daddys are $200 shipped), Autolite 104 plugs, 180* tstat and a cold air intake (you can make one for $40 if you want)
The following is from ZZPerforamnce.com (Don't rely on ZZP, but this is legit info)
97-03 Grand Prix & 04+ supercharged Impala & Monte Carlo SS
3.5 pulley totally stock car
3.4 pulley Colder Tstat & spark plugs, downpipe, Cold air intake (still could have KR)
3.3 pulley all of the above plus a VS cam, SS intercooler, or headers
3.2 pulley 3.4 mods and a XP cam
3.0 pulley 3.4 mods and a fullsize intercooler or an SS ic and a VS cam.
Anything smaller than a 3.0 pulley will require a camshaft, headers, intercooler & injectors.
04-05 GTP or Comp G & 06 GT supercharged
3.8 pulley totally stock car
3.6 pulley Colder Tstat & spark plugs, downpipe, Cold air intake (still could have KR)
3.4 pulley all of the above plus a VS cam, or SS intercooler
3.3 pulley 3.4 mods and a XP cam
3.2 pulley 3.4 mods and a fullsize intercooler or an SS ic and a VS cam.
Anything smaller than a 3.0 pulley will require a camshaft, headers, intercooler & injectors.
Originally Posted by W-Body Store
08-25-2011
It might have been fine for a while, but with knock, it probably didn't last too long...
Originally Posted by W-Body Store
08-25-2011
I think you would be fine doing a 3.6 on a stock tune MAYBE. The problem is that the file in the PCM is a cookie cutter file so you could be having more KR or less KR than another car with the same stock file. Adding a smaller pulley to a already knocking stock car is not going to help it.
08-25-2011
First and best mod you can do starting off. Pontiac Performance Racing Products for International Sales from SSAutochrome Inc.
2nd is a Homemade Fenderwell Intake.
Search for this on the forum.
08-25-2011
How about you research.
Buy some headers.
They are the price of a PCM and would do way more good for your car. Just because someone had a smaller pulley doesn't mean it is the correct path to take either. I'm sure you could run a 3.4" on a stock car with some 100+ octane and it'd be fine. But you can't just fill up with race gas everyday...like I stated before...let the car BREATHE BEFORE BRINGING MORE AIR IN...EXAMPLE: Too small of a pulley with no flow mods (and don't say catback because the factory ones flow up to 300+ FWHP...which your putting out MAYBE 200 to the wheels, most likely less)...it makes all that boost but can't get rid of it...sh1t gets pissy...sh1t gets hot...sh1t chips pistons and breaks. Go ahead and toss a smaller pulley on, I honestly don't care. Come on here and ask questions but still go about it thickheaded isn't the best plan. We've been where you are...we know these cars. I wouldn't recommened something to you I wouldn't think would work. But if you put that smaller pulley on there without headers or a PLOG/DP combo...don't come back here crying when it assplodes all over the pavement...bruh.
Click the link in my signature like stated. Were here to help...but if you don't want to listen then idk what to tellzya.
08-26-2011
Welcome!
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