pulley Upgrade Question!

[silverluminaZ34]

I have a 2002 Pontiac Grand Prix GTP. i currently have a Cold Air Intake, and u-bend delete and resenator delete. my questions is if i put a 180 thermo stat and autolite 104 plugs with all those. will those mods support a 3.4 pulley? if not what else would i need? thanks i need help!

[BNaylor]

Those are the typical supporting mods for a 3.4" SC pulley, however, to be sure you will need to use a scan tool capable of checking for any knock retard (KR). Then you can decide whether any further exhaust mods are needed like a bigger down pipe, PEMs or even headers. It is highly recommended to use a re-programmed Stage 1 PCM module from ZZP, DHP or Intense when running a 3.4" pulley.

[silverluminaZ34]

Originally Posted by BNaylor

Those are the typical supporting mods for a 3.4" SC pulley, however, to be sure you will need to use a scan tool capable of checking for any knock retard (KR). Then you can decide whether any further exhaust mods are needed like a bigger down pipe, PEMs or even headers. It is highly recommended to use a re-programmed Stage 1 PCM module from ZZP, DHP or Intense when running a 3.4" pulley.

Well i decided To have a well known (trusted) mechanic to do my 3.4 pulley and plugs,thermo ect. When he checks for (KR) Would you know a range Where its alright and what it would read for me to have to do somthing about it? im not to familiar with (KR) But the mechanic is. Im just nervous, this car is a daily driver. With all those modds i just want to be sure i can support that pulley?? Please get back to me with any info that might help. thanks

[tblake]

Here are the Mods I've got. My car is used as a DD and does a good job. BTW, I bought the 3.5" pulley before any other supporting mods. Otherwise I would have gotten the 3.4".

In a perfect world, KR would be 0. Not sure what the highest it can safely be.

[BNaylor]

The problem is you will never see zero KR. Plus there are too many variables so each L67 GTP will be unique as to how KR you see or may be present. It needs to be checked before mods and after mods just to be sure and safe. I did not see whether a re-programmed PCM was going to be used. I would not recommend going to a 3.4" SC pulley without one. There are different types of KR across the power band when you check it with a scan tool capable of reading it out. WOT, burst, shift KR, part throttle, etc. in which the modified PCMs like from ZZP, DHP or Intense, etc. either negate or manage better. Even the quality and octane level of gasoline used may affect KR and give readings of 1-2 degrees.

[silverluminaZ34]

Originally Posted by BNaylor

The problem is you will never see zero KR. Plus there are too many variables so each L67 GTP will be unique as to how KR you see or may be present. It needs to be checked before mods and after mods just to be sure and safe. I did not see whether a re-programmed PCM was going to be used. I would not recommend going to a 3.4" SC pulley without one. There are different types of KR across the power band when you check it with a scan tool capable of reading it out. WOT, burst, shift KR, part throttle, etc. in which the modified PCMs like from ZZP, DHP or Intense, etc. either negate or manage better. Even the quality and octane level of gasoline used may affect KR and give readings of 1-2 degrees.

Well my questions is, it will be a few weeks until i get my reprogramed pcm. my question im asking, is to see if i will be ok until i get the pcm? can it make that big of a diffrence? my car is in the shop getting the pulley put on. im just trying to be safe then sorry.

[BNaylor]

We would be speculating as to whether it is OK or not. I'd hate to tell you it is OK and then you wind up with driveability issues. If the mechanic has a full function scan tool capable of reading out KR see if he can run realtime testing on it just to be sure and safe. In the meantime until the new PCM arrives just don't hot rod it. If the KR gets bad you should notice it or will hear or feel detonation/pinging and the engine will stumble until it recovers. It is your car and call.

[silverluminaZ34]

Originally Posted by BNaylor

We would be speculating as to whether it is OK or not. I'd hate to tell you it is OK and then you wind up with driveability issues. If the mechanic has a full function scan tool capable of reading out KR see if he can run realtime testing on it just to be sure and safe. In the meantime until the new PCM arrives just don't hot rod it. If the KR gets bad you should notice it or will hear or feel detonation/pinging and the engine will stumble until it recovers. It is your car and call.

SOUNDS GOOD! Thanks for all your help. i will keep ya up to date when i get the car back! Thanks again!