97 gtp pully change

[MUbodbuilder]

hey all im new here and im looking to increase my cars HP without spending too much or causeing damage. iv been looking into the 3.4 and 3.2 pullys and would like to do the 3.2 but iv read a little about it and the extra mods neccessary. iv got cold air intake and magnaflow straight pipe exhaust. can someone tell me a little about the parts i would need to run a 3.2 pully size? im not sure how much they cost or where is best to get them. iv also read about needing an intercooler, my brother put his own on for his turbo'd car and said he could help me do that on my own if thats possible??

thanx for the help in advance

[BNaylor]

Welcome to AF.

I would not run the 3.25" pulley unless you have supporting mods installed. High probability you will run into excessive knock retard (KR). You'll need exhaust mods to keep KR low. Bigger downpipe, PEM or headers. Even with a 3.4" pulley I'd run an Autotap test on it or get a scan gauge like an Aeroforce Interceptor to monitor it. Also, to start a re-programmed PCM module. Do you have one installed?

Intake mods like an intercooler would help keep KR in check and provide the biggest hp gain. Definitely available for the L67 engine. Most of us get our mods from 3800performance.com, zzperformance.com or pfyc.com.

[MUbodbuilder]

http://cgi.ebay.com/ebaymotors/GM-38...mZ180089100687

take a look at this sale. he is offering a 3.325 size and claims it dosnt reguir an intercooler. i dont plan on spending a lot of money so im avoiding the intercooler deal yet sticking with the smalled possible size. do you think this size would cause some problems? i will probly just get a 3.4. i have not yet ordered a PCM, im trying to find a used one so its cheaper and i can keep my old one. i read on one of the sites u listed that a 97 gtp shouldnt need a check up after instalation of a diff pcm unless the engine light goes on.

thank you for your help and bearing with me in trying to learn

[BNaylor]

I'm not familiar with the brand/company but it looks good to include price. The modular pulley system is the best to use over a standard pullley system.

You really don't need an intercooler to run that size pulley. Below 3.0", yes. The problem is you will need to monitor for any knock retard (KR). Even with the colder spark plugs and CAI you may get unacceptable levels running anything pulley smaller than 3.4". I would not run any pulley less than 3.5" without a re-programmed PCM module.

As far as checkup, when you replace the PCM module a crank variation learn is normally recommended but not required. The PCM will tell you by giving a SES/CEL light and possibly a crankshaft position sensor error code. The best test is to install it and see if the car even starts, runs and no errors are triggered.

[johnb2334]

About 8 months ago I had to change my nosecone on the super charger and it came with a 3.5 inch pulley. I read this blog and just had a quick question and hope Im not being rude by asking a question on someone elses blog. I was told that the 3.5 would be fine to run without making any changes. I have noticed that I have an idle problem at times that ranges from 800rpm to 1000rpm. I also notice as Im going down the road and I let off of the gas pedal my rpms will dip below 1000rpm's and then shoot back up to 1800rpm's or so. Could this be because of the pulley by chance? Thanks

[BNaylor]

Originally Posted by johnb2334

About 8 months ago I had to change my nosecone on the super charger and it came with a 3.5 inch pulley. I read this blog and just had a quick question and hope Im not being rude by asking a question on someone elses blog. I was told that the 3.5 would be fine to run without making any changes. I have noticed that I have an idle problem at times that ranges from 800rpm to 1000rpm. I also notice as Im going down the road and I let off of the gas pedal my rpms will dip below 1000rpm's and then shoot back up to 1800rpm's or so. Could this be because of the pulley by chance? Thanks

Possible but chances are there may be another cause. The supercharger is really not used in high engine vacuum-idle conditions. What is your current mileage?

An erratic idle can be caused by a dirty/malfunctioning idle air control (IAC) valve or throttle body. Also, MAF sensor and TPS.

To troubleshoot possible supercharger problems all you have to do is remove the SC drive belt and then test it to see if the problem went away or is still there. You can run normally without the belt hooked up.

[MUbodbuilder]

alright that makes sense. thank you for the help. so if i get what your saying then i should get a PCM instaled and checked before getting this pully size?

[BNaylor]

Originally Posted by MUbodbuilder

alright that makes sense. thank you for the help. so if i get what your saying then i should get a PCM instaled and checked before getting this pully size?

That is correct.

Better safe than sorry. KR is bad stuff and the improved programming of the aftermarket PCM modules adjusts for it and allow a smaller SC pulley. Good luck.

[MUbodbuilder]

alright so i have ordered everything but the colder plugs you speak of. i went down to good ol auto zone and they didnt have anything and the guy behind the desk told me colder plugs would be condradictory for what im doing and i want hotter plugs. !!?? i walked out thinking he didnt know what he was talking about. so now, what plugs should i use? specific # of them maybe? i have found some is this what i want?
NGK Iridium plug 5599 ITR4A-15 0.060 SUPERCHARGED

[BNaylor]

Most of us with modded GTPs use Autolite Copper Core spark plugs. Reason is reasonable cost, availability and the easy numbering system as to the heat ranges. You can get them at Walmart. The link below will describe it better.

Click here

However, they do not last as long as the Platinums and Iridiums. Autolite APP605(double)/AP605(single) Platinums will work fine for a 3.4" SC pulley and last a long time. As will NGK spark plugs but I do not have the heat ranges off the top of my head.

As far as the advice from the Autozone parts guy on going to a hotter spark plug.

[MUbodbuilder]

ok so i got some serious problems here now. i got the pcm, traded out the little chip under the plate on the side. put it in now problem. but iv taken my car to 2 places and both say they cant get my stock pully off. one of the places was even a GM dealer which i figured would be able to do it if anyone could. they said they got the belt lose and the pully clamp thingy on the pully but it just wouldnt budge. the only other method they suggested was taking off the supercharger and completly desembling it and then they still wernt sure if it would come off. and a bill would be reaching $400. any ideas?

[BNaylor]

What type of pulley puller are they using? It takes the special SC pulley puller like from ZZP or companies like Pulley Boys. They are made specifically to remove the pulley on an Eaton M90 blower. Not just any common pulley puller will work. I have the one from Pulley Boys.

Click here for ZZP

Click here for Pulley Boys

[04GTP-WhatLAG?]

this site seems to not be working now:

http://alpineecho.com/catalog5/default.php/cPath/2

but that is where i got my puller, and it worked like a charm...

[MUbodbuilder]

i have no clue what they were using. im guessing they SHOULD have the right parts. i mean they sell other GTP's so it seems like they would have had a pully remover for the job. but thanx guys this gives me hope that i can still put on this new pully. maybe its worth it to buy a pully remover myself and do this?

[BNaylor]

I wouldn't make any assumption when it comes to the dealers. You would think they knew what they were doing but it is normally not the case. Dealers don't even carry parts for the blower with the exception of the supercharger oil.

I would get the right SC pulley puller. It will pay off in the long run especially if you have plans on replacing the pulley later. Definitely a DIY job. Good luck.