Well i installed nates 2.9" pulley today and had to go to work..drove it to work and everything...perfectly fine..didnt really get on it..well on my way home from work i floor 2nd and 3rd gear and all im seein is 10PSI...with the s2 pulley i saw 15psi some time 15.5psi..i did take the negative charge battery off for about 15min after i drove the car around...my plugs are gapped to .039...anyone knw what the problem might be?im on the stock gm s2 tune..was bout 72 degrees when i did the runs

HELPPPP

 

was it really really hot out

 

no..about 72 with some cold wind

 

oh well hell i dunno

would ur intake cause it?

 

tx for the help..i was so happy when i got the pulley installed and everything,and than i find out im boostin 10psi...WTF

Bump!!!!!!!!!!

 

Put Nates 2.85" on Tuesday and saw 17 psi right away top of 3rd in 80 degree at sea level. Boost also came up way faster with this pulley vs S2 one. Neg bat cable was off for a few hours as we had to remove supercharger to get old pulley bolts off. Used 1 step colder NGK plugs gapped at .040 and all is fine.

 

do u have 2 balts or 1^^

 

Sorry for the confusion....Just this one and it's one of my sons cars, but I do pretty much all the wrenching on it right now while hes watching/helping/learning on this particular car so I'm the one doing all the posting of questions and such.

 

u think i would need to re-gap my plugs and take the negative terminal off for cpl hrs as well?

 

I think your plug gap is probably just fine. I know other people on here say to disconnect the neg terminal for at least 30 minutes, but I really don't know if its a time thing or not. Id say your gauge might be off, but doubt that if it was working fine before and not after. It couldn't hurt disconnecting it again for an hour just to see.

 

It has to be something with your belt. Make sure it is on the crank at the bottom. I know I had to play with it to get it on. I put the 2.9" on with no problems.

 

The only thing with the belt that would cause loss of boost would be severe belt slippage and you would probably hear it if that was the case.

 

gap your plugs to .35, check the tension on the belt and make sure you don't have any vaccum leaks. that will cause it otherwise.

 

Well if all he did was remove the belt off the pulley and install the new one, what else can it be? Yeah I know slippage would do it, but it shouldn't be slipping. I dunno, let us know what it is when you find it.

 

A difference between .035 and .039 plug gap is not gonna make a 5.5+ psi difference in boost. I'm not sure where the boost gauge hose plumbs into but track it down and make sure its not leaking somewhere. If it was leaking vacuum reading at idle would be way off as well though.

 

i am interested in what this turns out to be, i am thinking it either has to be the belt or a vacuum leak if the supercharger was taken off to put on the pulley.

 

Yeah did you take the blower off or just remove the pulley?

 

well its thursday morning and i couldnt sleep since i had this on my mind..i usually sleep till 11am or so but no today...i go to garage to check out everything and review make sure i did everything right...

belt..........done
vacume line........done
spark plugs..had a shop install them for free and gap them,and they gapped them to 0.24..
i had them gapped myself before i installed the pulley and they were in the package ready for install since they were gapped...well looks like they gapped them again to a even more smaller size...i gotta run to the bank in a few,so i took the negative cable off and let it sit for a few before i connect everything back

just remove the pulley and loosened the tensinor..there's pics on the pulley thread...saved all the bolts and pulley...can reuse it easily

 

Def. set those plugs to like .037 or so, my car didn't really like 0.040 but somewhere in there should be fine. It had to run like **** being gapped that tight.

 

So the plugs that were in there when the boost was low were at .024? Or you had already changed them to 0.39 when it was running low boost? Who the heck would gap any plugs at .024???

Most people that gap plugs aren't gonna get them precise anyway so shooting for ..040 will yield anything from a .038-.042, especially if using one of those POS ramp style round flat looking gappers. When I did ours I just went .040 using a flat blade feeler and called it good and it runs just perfect.

 

got them down to 0.039 since my car usually see's little more boost than other cars,and i will be gettin a custom tune..so ill see what happens

when i received them from cobalt addication,i took them out of package and gapped them to 0.039...i go to a shop to install my pulley and plugs and they lost my key for the bolts,and decide to install the plugs only...well they install them,but re-gap them down to 0.024 before installation

well just came back from a test drive...gapped it to .039 and same ****...10psi max boost...

 

I dunno man. Something is up. I probably wouldn't run it hard till you figure it out either. I'm sure its running rich as hell up top if that is all you are getting.

 

do all the spark plugs(obviously yes) have to be on same gap...i knw #1 was on 0. 43 and the rest on 0.039..would that make it show way less boost?

also when u floor 2nd and shift to 3rd and take 3rd close to redlineu can feel like a fuel cut or belt slippage..

 

yea i have the same set up with stage 2 but with 2.85 and all i get is 15psi but 10? wow that definitely seems odd. Hope u find out what the problem is

 

You want them the same yeah but there is no way it should effect it that much. I'm gonna say it is something with the belt or a leak somewhere. It was a 2.9" you put on and not a 3.9" right?

That might be because its running really rich. Like I said i wouldn't run it hard till you figure it out.

You didn't do anything else right? Pulley swap and that is it? Nothing with the air intake or anything? I know I got my MAF wet before and it ran like ****, felt like the fuel-cut was kicking on at like 3,000. Try turning the pulley with the belt on when they car is off. It should be really tight and should be kinda difficult to turn. Make sure it is in neutral too.