well I have a 04mcs. Just got alta 17% pulley, boost gauge, and a helix cai, and im getting around 14 psi boost,
is it supposed to be 16? when i am in the car under WOT and it hits around 4*5k it sounds like the belt is slipping,
or if i am sitting still and revving the car and it hits around that it sounds from inside that the belt is slipping,
but i had my friend rev it up for me and listening right next to the belt/supercharger i dont hear a slip. Is there something wrong?
i have intake, 17% pulley 91 oct and stock plugs. I'm getting 14 psi till about 5k then it comes down to around 10. my vac at idle is aroun 20

 

sounds like a belt...I get max out right around 15-16psi, with no drop offs. what kind of belt you using?

 

It would also be highly advisable to get some colder plugs.

 

060539 belt. What plugs should I run? What is the gaping in the plugs also.

 

It kind of dumb if they suggest that belt and it's the wrong size.

 

Get Napa 060535 belt, it is hard to get on there, but it will not slip.

 

Which plugs?

 

most of the plugs from most of the mini vendors on here are the colder ones and are pregapped for the mini.

 

JCW spark plug or BRISK silver racing spark plugs

 

Did you check the belt tensioner first ?

How many holes are showing out the top right now ?

The NAPA Belt is the ONLY one to get IMO as well.

I had similar issues two months ago with my 03' so I checked the belt tensioner and saw that I had less than 1/2 a hole showing at the top......swapped it out for a new NAPA belt and now pushing up to 17 psi at WOT.

And while you are in there, check for any main bearing seal leaks on that side. I had some seepage issues, the MB gasket needed replacing.

 

I have zero holes showing, when it revs I can see it close to bottoming out the end of the shaft.
Looks like I'm getting a new belt

 

Yes, definitely get a new belt with no hole showing. FYI, Gates makes Napa belts, so get Gates if you can't find Napa...........same belt.

BTW, when first installed, don't be surprised if it looks like this...


But then after you run it a little, it will settle into this....


Still a whole hole, this was a few months ago for me with a 15% pulley, you will have ever so slightly more slack, or less hole with a 17%.

Good Luck and enjoy full boost!

 

One of the best bets for plugs are the JCW OEM ones. They are NGK 4 prongers.

http://www.ngk.com/results_cross.asp...R7EQUP&x=0&y=0

 

Behe Performance (Lucky Dog Garage) specifically recommends against a pulley more than 15% because the performance curves on the stock sc start to decline over specific RPMs that are below redline. This may be your problem. The advantage of the 17-19% pulleys is that they provide higher boost at lower RPM.

 

Yeah, i cant even see my hole. I ordered my stuff through outmotoring, i got the napa 060535 belt and the tensioner tool today. Hopefully everything goes smooth when i get the stuff in, cant wait for more boost, right now with the belt slipping it is still making a big difference, its great!@!

 

When I got that belt installed I needed a 2nd set of hands to help cause it was so snug. Then again, I did not have the tensioner tool and was using a pieced together pry bar set-up. Having the tool will be easier, but this size belt will still be more difficult than the 539.

Good Luck, and enjoy full boost!

 

well the belt install was not that difficult once i figured out it was easier to run it around all the accessories then loop it around the crank, went on like a piece of cake then.
ok well im peaking at 15psi of boost. i guess that is all i can expect out of it. i have 1 hole showing now not 0.

 

well now its a 1/2 hole showing, not even getting boost past 14lbs

before i changed the belt i would spike at 14lbs at 3k now i dont start building past 10 till around 4.5k and it.

from 2k itll show 10lbs and stay there till i hit around 4.5k, kinda dumb

 

here is a pic of the tensioner

 

Question: How much boost am i getting from my 15% alta pulley and cai?

 

Do we have any updates?

 

Well, I just installed a Detroit Tuned bypass valve this past weekend. My boost went from 15 psi to 16 psi at WOT. I however have more than half a hole showing on my tensioner tab. I want to go on a head and change my belt. I have a 15% s/c pulley and a 2% oversized crank pulley with a gatorback belt (forgot which one it is). Any suggestion on a belt for this set up. I need to go to Napa and get an exhaust band clamp, so while I'm there I'd get the belt too. And for the OP, do you guys think maybe his bypass valve is faulty also?

 

i have a 15-2 setup also and max ~18psi @6500, looking to add a DT BPV soon. your problem sounds like a belt, had the same problem on mine.

the belt began to slip off of the grooves and actually tore and ripped to shreds... i had no boost, no a/c, no water, no oil... i drove on it for a mile at 5mph... lucky i didnt overheat it and crack a head

 

are you feeling/hearing this drop in boost? Dropping 5psi is VERY noticeable. the car falls on its face, and you can hear a strange whine coming from the belt.

and i would like to know how you was getting 14psi at 3k...there is no reason it should be that high at such a low rpm. as your rpms rise, your psi should rise in unison...as the engine turns faster, ur sc turns faster, thus your psi goes higher...you sure that boost gauge is accurate?. youre not turbo'd

 

2 problems I found out
1, belt i originally ordered was too small.
2, i had power steering fluid on the correct belt when i replaced it. Took a couple days to clean off, now its running good. Getting about 15-16 psi o boost. Running like a champ. Really like it.