Sharkey

iTrader: (1)

ott supplies a larger tensioner pully but not the tensioner bracket itself, the bracket is what needs to be modified

TRANSAM197781

iTrader: (5)

ah i see now i get it thanks for clearing that up

csementuh

iTrader: (18)

OK... Why not just buy a Stage 2 belt and use the stock tensioner as is... I am running a 2.7" with the Stage 2 belt and stock tensioner with zero belt slip... Why even bother with an oversize idler pulley when the Stage 2 belt costs like $45 bucks?

Also, as everyone has said, the stock boost gauge is slow and inaccurate. With my mods, 2.7", RAW Intake, LS4 TB, Ported M62, Header & DP, I only make like 17psi at best according to the stock boost gauge... I assure you it is all about the flow, don't worry about the boost... You are still cramming wayyy more air into the engine...

mjesenovec

Thanks man. my car pulls like a monster compared to what it did on the stock pulley. i never said i'm not making power...because i definitely feel a huge difference. the car just wants to rocket out of control now...it's amazing. if the stock boost gauge isn't entirely accurate, i can live with that. the thing that bothers me most is the slipping KSHHH noise at high rpm's. if it wasn't for the noise, i wouldn't mind the boost reading at all. My bro and i will mess with the stock belt and larger idler pulley possibly next week. I dont care so much if i get more boost on my gauge, i just want that noise to go away. Now, if we do this, and the noise is still there...i dont really know what to do. i guess i'll just have to live with a car that sounds sick at high rpms. I dont mind grinding down the tensioner bracket, and putting the stock belt on doesn't bother me at all...i just want the damn noise to be gone. Maybe if someone on here lives close to the chicagoland area, we can meet up sometime and i can show you the noise i mean.

qwikredline

i am afraid to ask what cat you are running?

Sharkey

iTrader: (1)

are you sure the noise is actualy belt slip and not just the blower whine??? my blower with the 2.85 is quite loud above 6000rpm. ive never had belt slip, however people that have say they notice the boost gauge fluctuating, or the boost just drops when it starts slipping, also acompanied by a noticable drop off in power.

just more food for thought.

mjesenovec

I have the ZZP header/downpipe combo with the magnaflow high flow cat...why?

oh my blower sounds amazing. it's the loud grinding/slipping KSHHHH noise that doesn't sound like blower whine.

lsjwannabe

iTrader: (1)

Any belt shavings?

bingo, its a 5 min job with the right tools

mjesenovec

not that i notice, no. no belt shavings. that doesn't explain the noise that SOUNDS like a slipping belt though. when i rev it at a stand still, i hear it...and it's loud. when i'm driving at WOT, i here it above like 6400rpms.....it sounds like something is slipping. i even notice a slight difference in power. like above a certain rpm the pulley just doesn't spin like it should. i might be crazy, but there's definitely a sound.

G85 SS

Interesting...I'm boosting ~17.5 pounds on a 2.9....

But keep in mind Boost does not = power. For all I know, you at 15 pounds is faster than I at 17.5...

And like lsjwannabe said. If the car feels strong, no need to worry about the boost.

Ok...hmmm, well, keep talking to him and they'll get it straightened out for you.

mjesenovec

true, but i do notice a dip in power when i hear the noise while driving at high rpms. like when taking it to redline and shifting.

G85 SS

Yea, that's definitely a little weird. Whelp, I don't have any ideas for you. But I'm sure lsj will be able to help you figure it out. He's been a lot of help to me when I've had questions.

mjesenovec

I hope so too. it's definitely not a little "oh well" noise. i mean it's not horrible...but it's definitely noticeable over the supercharger whine. and i even made sure to line up the new pulley flush with the supercharger rod. it's not like my pulley's are not aligned or anything. everything is straight, and i still get this godawful noise when i rev. again...i will drive it around for a week, and possibly next friday or so, my brother and i will use the stock belt and the larger idler pulley. it's possible this will fix my problem....if not, i'm clueless as to what it could be.

fzn14

Ah well its good to know i am not the only one here. BUT i have a OTT with Vibrant down pipe and tune by area and sometimes with my 2.8 i will 18 but most times i hit 16ish, just kinda depends on the time etc etc etc, but as far as with running lower boost, i ran a 13.8 on 16ish pounds of boost with the DP and tune. I my boost does flex sometimes but never am slower so i am not to concerned...And with you i wouldnt be..do some cooling mods and go from that

csementuh

iTrader: (18)

The only real way to prove it is belt slip would be to have your car scanned with HP Tuners... When you are viewing the logs you can noticeably see the boost fluctuate and fall and other things. Find a friend with HPT and take him for a quick ride...

If it is slipping I recommend you put back on your stock tensioner and buy a S2 belt... They work just fine with a 2.8"...

You ever think it might be your Ingalls ETD making that noise? They are known to made some weird noises sometimes and can even make the engine think it's knocking sometimes...

mjesenovec

Interesting point. I dont think it's the ingalls because it's definitely some sort of moving part causing this noise. remember...when flooring it at idle or while driving, the rpms get up, and you hear WHAAAAAAAAA KSSHHH. horrible grinding/slipping noise. sounds like something soft rubbng on something hard. it doesn't sound like metal on metal...it just sounds like friction somewhere.

My buddy with HPTuners just had knee surgery. when he's feeling better, i'll swing by his place and see what he thinks about the noise...then we can do a diagnostic WOT throttle run on an empty road by my house. I actually am running my stock tensoner pulley and a stage 2 belt. the belt is from my buddy's old ion redline. i got his belt after he totalled the car in case i ever needed it. no visible damage. He was dumb though with his redline. he had a GM stage 1 tune, stage 2 injectors, and a 2.8" pulley. had it dynoed at 238whp. lame. i was waiting for it to explode.

but i digress...i'm running the stage 2 belt and the stock idler pulley. i'm anxious to see if this noise goes away when i do the oem belt and the larger idler pulley. i dont really care how it's set up as long as i dont have to listen to this noise, and i still get all my boost.

mjesenovec

i played around a little after work. i did a WOT pull in 2nd. smooth as hell until about 6k rpms. then i could hear the slipping noise and felt a difference in acceleration. instead of a strong steady clim to redline, once the noise starts, you can feel the pull cut back. it still goes to redline, but after 6k rpms it doesn't pull while the "noise" is happening. the boost was a pretty constant 15psi, and i'm pretty sure it stuck at 15 to redline...but there was a definite drop in acceleration power.

lsjwannabe

iTrader: (1)

If the boost is not fluctuating it does not seem like it would be belt slip.

Is the clutch slipping at all?

mjesenovec

well i dont know for sure if the boost fluctuates, i wasnt paying that close attention while paying attention to the road. I do however feel a dip and fluctuations in power while in WOT. The clutch is not slipping one bit. Like i said, the noise occurs at a dead stop, clutch pushed in, full throttle rev...and while driving full throttle when the motor is under load.

mjesenovec

Also, i dont know even though if this matters, but last night i shined a flashlight on the belt when i got home, and there were these tiny clear crystal like hairs. almost looked like fiberglass dust. thought it was kinda strange. Also, i had 1 2nd gear pull to redline when i didn't hear the noise or feel a loss in pull. it felt smooth and strong that one time...then every other time after that i heard the slipping/sliding, high pitched screech. hmm...

ShortStack

nope mine has that too (the hairy stuff)

mjesenovec

well it's good to know that's not abnormal then. I'll keep an eye on my belt to see if i notice any shavings or anything. I'll go find my dremel so my brother an i can replace the belt on friday and put on the larger idler pulley. i hope to god this fixes this stupid noise.

ShortStack

i jsut dont get why yours would do it and no one elses would...

have you tried belt dressing?

mjesenovec

yep, i tried that the day after i put my pulley on. OTT suggested trying it. it seems to get rid of the noise for 2 or 3 WOT pulls, then the noise just came back. I sprayed both sides of the belt evenly.

ShortStack

hmm...

it could be one of the other pullies....

there could be residue, or some type of object in or on the pulley... or a coating could have just come off and the belt is just being rubbed too hard...

lets see what happends wit the idler!