I have made a few threads about belt slip and boost leaks over the past couple of months. When I first started having issues it was because my belt was way too lose (The belt I have on now is about 1 1/2 inch shorter, I am amazed it didn't slip on the dyno and lasted for a few weeks). I had heard a whistling sound after about 5-6 psi a little over a month ago. This prompted me to do a boost leak check on my car. I found a bolt missing on my intercooler and this was a significant leak as the air was rushing out of this bolt hole! I put some silicone on a bolt and put it in the hole and expected to jump in my car and the problem would be solved. Drove down the road, got on it and heard the same whistle. So now I was really scratching my head as my car would hold pressure and I couldn't find any leaks. This lead me to replace the o-ring in my bypass valve. For a second it seemed to fix my problem but my car still wouldn't boost past 7 or 8 psi but it was better then the 5 or 6 I was getting before. I now have a nice tight belt on there but I am still getting this whistle over about 5 or 6 psi of boost. I am also getting this whistle if I rev the engine fast while in neutral or with the clutch pushed in. This is making me think that my belt is slipping as it's not boost related but when the engine is reved quickly. My best guess at this point is that my loose belt that was originally on there slipped so badly for so long that I may of smoothed the pulley on my Vortech and since the pulley doesn't have as much traction the belt is now slipping even though it is tight. I even have the GTM pulley upgrade but you can definatly tell that the noise is coming from the supercharger area when you rev it quickly with the hood popped. Could I of smoothed my 3.12 supercharger pulley so badly that now it won't grip? Could I rough it up with sandpaper or something to get it to grip again? Any advice would be much appreciated!

 

check to see if Bogger still has his clog pulley set up. Should have went procharged they don't slip clog belts I never had a problem even if they were a little loose.

 

I hear ya but I shouldn't be having these problems at the boost level I'm shooting for.

 

But it seems to enjoy chewing the belts..

 

I don't really know that much about superchargers but cant this problem easily be fixed if the design of the belt and pulley was more like that off a chain and sprocket?

 

I don't want to turn this into a Vortech vs Procharger debate now lol

 

wait abit some vortech guys will chime in its still early And bogger was shooting for high psi #'s over 12 thats when any supercharger has problems.

 

gadder back belts....best belt for s/c that like to slip instant fix for all three friends with JR s/c kits.

 

I doubt your belt is slipping if its tight . The best way to find all boost leaks , is to cap off your exhaust and preasurize the system .

 

you are so wrong..... gator back is one of the worst belts for the 350z vortech s/c kit. i should know, i blew throught several of them originally. gates or bando serp belts work the best for the vortech kit. i am pushing 14psi out of my vortech with no belt issues.

 

Hey Booger, I'm the one who did that DIY on that homemade boost/pressure test kit. I don't have any leaks at all. Plus wouldn't reving my engine really quickly and causing this whistle/squeal sound be a belt slip issue since I'm not making any boost when just reving my engine quickly from say 1500 rpm to 4000 rpm. I will post a video of this but I am almost positive this is belt slip. My main question is can I rough up the 3.12 pulley with some sandpaper to try and create more traction? Any other ideas? I will look into a new belt too. Any idea where they can be purchased? I have been buying all of my belts from NAPA.

 

I went to the 2.87, I should have my 3.12 sitting somewhere in the garage. What belt are you using? I switched to the NAPA belt (gates) and haven't had any issues.

 

you can sand blast the pulley to take off the anodize and get a little more grip . But if you think it is belt slip.....your belt just isnt tight enough . Like JetMech said....12 to 14psi is where the serp belt will slip from the blower being to hard to turn .....IF.......its tight enough.

 

log a pull and plot the boost vs rpm.

you will easily see if belt slip is really the problem. Sounds like you are still guessing that its belt slip. I run up to 15 psi with the standard napa belts and stock belt arrangement with 0 problems with slip.

 

I am 90% sure this is belt slip. It is worse when the engine is cold and first starts up and gets better after it is warm. Tonight is was cool in the mid 60s and I started it up and just bumping a little on the gas pedal made it squeek / whistle. I am using a napa belt size 25-060926. What really pisses me off is that even with the tensioner taken all the way in I could bearly get the belt on. I had to get it partially on the last pulley and blip the engine to get it to catch and stretch on to all of the pulleys. SO I figure I am about as tight as I would want it and have the full range of the tensioner to tighten it even more. Yes I loosened the 14mm bolt that locks the tensioner pulley in place, but it seems like there is very little range on my tensioner travel and it didn't even seem like it tightened the belt up anymore. I feel that even so I still have enough tension on my belt. I don't even get a squeek on start up and my belt makes no noises even when cold. I have a spare 2.87 pulley and when I rub my thumb on it it feels grippy. When I rub my thumb on my 3.12 pulley that's on my car it feels super smooth and almost like it has a slick glaze. I will see if I can use my friend's sand blaster but if not are there any other suggestions on how the make my pulley more grippy? I may just order a new pulley from vortech and be done with it but I hate to spend the money if I can just fix the one I have. I think the sand blasting is the best option though.

 

Yup it's the pulley. I just sprayed a liberal amount of belt dressing directly to the pulley with the engine running and took it out for a drive. 10psi back to normal! Finally! I haven't seen over 7 psi in about 2 months!

 

wow thats interesting.
glad you got it all sorted!

 

Man, that's frustrating. I'm glad to see you finally figured out what it was though.

 

Yeah the good news is that I have finally isolated the problem to being the pulley. The bad news now is that the belt dressing only fixes the problem for about half a day. I am still going to need to figure out a way to rough up the grooves in the pulley to create some traction I am going to look into sand blasting the grooves to try and get rid of the super slick glazed surface. I may even try to stick a corner of some 80 grit sandpaper in the grooves as the engine is running so I don't have to take everything apart. I guess worst case I can just order a new pulley from Vortech.

 

qhy not take 100 grit sand paper start the car and hole the sand paper to the pully this way you dont' have to take everything apart. Its just a thought