3.5" Pulley

**RedGrandPrix** · 08-29-2008

Hey guys. I know there has certainly been a lot said about changing the size of the M90 Eaton pulley, but you guys have had much more experience than me so I would value any input on the matter. I currently have a 99 Pontiac GP GTP. The current upgrades so far are:

AC DELCO 41-985 (iridium 1 range colder 0.055" gap)
K&N FIPK CAI
180* T-STAT
U-Bend DELETE
BRAND NEW Port and Polished high performance M90 Supercharger

I live in CA and give it the highest octane we have here (91). Do you think it is reasonable to go to a 3.5" pulley? I understand I should scan for KR no matter what.

Thanks for any and all responses.

**Street Wolf** · 08-29-2008

Get a better CAI than that K&N junk, and drop to a 3.4.

**RedGrandPrix** · 08-29-2008

I'm pretty sure K&N is the only one with a CARB exemption sticker. The emissions people here will fail a modified car outright without one the minute they pop the hood.

**IndeedSS** · 08-29-2008

Originally Posted by Street Wolf

Get a better CAI than that K&N junk, and drop to a 3.4.

Piss poor advice.

**Street Wolf** · 08-29-2008

Originally Posted by IndeedSS

Piss poor advice.

Uh huh, sure.

**IndeedSS** · 08-31-2008

Originally Posted by Street Wolf

Uh huh, sure.

I know you missed the part where the only exhaust mod was a ubend delete. For a 3.5, at the very least a DP, needed to be added to his list. Still likely even with those mods, the only way to run KR free would be a PCM with a 10.6:1 AFR with reduced WOT timing. A combination of slow. I just don't get why after as much time as gone by and as much information available people are still recommending pulleys that are too small for the mods, instead of working the in order of optimum AFR>Timing and then go with the pulley that fits the build.

OP-go with an Overkill PCM :: Overkill Motorsports ::

**offroadfury6** · 08-29-2008

Originally Posted by RedGrandPrix

Hey guys. I know there has certainly been a lot said about changing the size of the M90 Eaton pulley, but you guys have had much more experience than me so I would value any input on the matter. I currently have a 99 Pontiac GP GTP. The current upgrades so far are:

AC DELCO 41-985 (iridium 1 range colder 0.055" gap)
K&N FIPK CAI
180* T-STAT
U-Bend DELETE
BRAND NEW Port and Polished high performance M90 Supercharger

I live in CA and give it the highest octane we have here (91). Do you think it is reasonable to go to a 3.5" pulley? I understand I should scan for KR no matter what.

Thanks for any and all responses.

ur kidding? u guys dont have 93 octane???

**RedGrandPrix** · 08-29-2008

Haha. That would be no. I even called around. California is real weird about emissions.

**Street Wolf** · 08-29-2008

Originally Posted by RedGrandPrix

Haha. That would be no. I even called around. California is real weird about emissions.

Move.

**offroadfury6** · 08-29-2008

so is NC but every gas station (except the arabs) carry 87, 89, and 93... I think only shell stores carry the max of 92 octane

**blowfishRus6** · 08-29-2008

get a downpipe and a powerlog to go with that. you need to get air out just as good as you get it in

**GTPaddict** · 08-31-2008

Originally Posted by blowfishRus6

get a downpipe and a powerlog to go with that. you need to get air out just as good as you get it in

GET HEADERS SAVE YOUR MONEY

TDCRacing · 08-31-2008

Originally Posted by GTPaddict

GET HEADERS SAVE YOUR MONEY

Agree

TDCRacing · 08-31-2008

You need to scan first. nobody can tell you what to do or what is best for you to do without scanning. So let that be your next mod.

**blowfishRus6** · 08-31-2008

Originally Posted by GTPaddict

GET HEADERS SAVE YOUR MONEY

i agree also. my thing on that is tho headers arent always the easiest thing to put on and get to seal sometimes. plus they can be twice as expensive as the p-log and downpipe and he could most likly run a 3.5 with p-log and down pipe fine.

BUT incase you guys dident notice, he said he doesent know if you can change out anything before the cat-back in his state to pass emissions. thus rulling all of this out.

**04CompG** · 09-01-2008

its only 100$ more for the Pacesetters on zzp than buy just the dp and powerlog. get the headers.

**DnaProdigy** · 08-30-2008

Yea you should be able to run a 3.5 with little Kr. As you already know and as i will repeat make sure you scan. If you drop and are still getting Kr you should be able to easily reduce it to safe levels with a downpipe. If you want to be extra safe a plog and a PCM will let you run the 3.5 with virtually no problems. That in mind every car is different but the above is usually true for most cars.