i have a 95 trans am, when i bought the car i was told it had the 9psi pulleys on it. (6 psi gauge because of my ~6200 altitude)

the car didnt have a gauge on it when i bought it, so i kinda of had to take the word of the guy i traded cars with (he was a cop, so i thought i could trust him)

i had teh car on the dyno, and it shows the car is making right under 3 psi and falling off towards redline.
i was told this is a symptom of s slipping belt. so i replaced the belt.

i got a boost gauge on it and it is still only making ~2-3psi


this is my first supercharger and my v8, so i am still learning about all this stuff.
i tried to tighten the belt, but im not sure how tight it is supposed to be ( i looked at powerdynes website and all it says is 'tighten the belt')
the first belt i over tighten because i could smell it burning.

any suggestions?
anything i can do to verify what psi i should be running?

thanks in advance,

** please save the 'get rid of the powerdyne' comments, it came on the car, and a pt76 is in the works

 

I used a pry bar and held it against the pulley and the ground and hit it with a hammer until it was tight. I made sure there was still some play but very little. I get the 2-3 psi like you with the 6.5 pulley.

 

Hello, The only thing that comes to mind is to check the entire system from the air filter to the throttle body for any air or vaccuum leaks or evidence of any colapsed tubing. Even the small stuff can make a big difference. Hope it helps.

 

Mine had a leak where the hose right after the maf is. There are two spots to put mounting brackets on and there are holes in them. Mine allowed air to enter so the sensor would not account for this extra flow. They have never corrected it to my knowledge. My psi also went down after adding Pacesetters mids since the restriction is less. If you want to read about Powerdyne just put it in the search thread and you can read for hours.

 

the second time i trued to tighten the belt, i used a pry bar to move the tensioner up and then tightened the bolts. ill try to redo it the same way but get it tighter.

is there any chance you can measure the pulleys on your car,
id like to compare the sizes, i might have the 6psi pulleys


thanks for the reply

 

i did a search, but there wasnt anything specific about tightening the belt.

i will check all the mounting bolt, and pressure test the system.

thanks for the suggestions and keep them coming.

 

I hardest part is doing it by yourself and keeping the tension while you tighten the bolt. I made sure i could move the belt up and down with little pressure about 3/8". Do any of you have the ability to datalog your car with the Powerdyne on it? I am looking for data that i can compare it to. My belt alignment with the pulley and crank shaft is off a little. Maybe this caused the burnt smell. My belt almost came off so i had to get it really tight after that happened. Unless you force the pulley to bend it is almost impossible to over tighten. Just be sure you have some play in the belt.

 

Its probably legit. You can see that kind of boost on a stock setup, but with a 383 in there and i'm guessing a more efficent exhaust and intake setup, thats probably why its running lower boost. With a give boost number, if you make the rest of your setup more efficent from an air flow perspective, then your boost pressure will drop. The real question is how much rwhp and torque were you making on the dyno?

Ken R.

 

on a dyno dynamics dyno is made ~290whp on ~2.8 psi of boost,

this is my first v8, and i know the motor is a low compression build (built for boost) so i have no odea where those numbers are, to me it seems low

and it seems low when it is supposed to be 9psi, imo, but please correct me if im wrong.

 

i am using a poly cog belt (from advanced auto) which is a replacement of what was on there when i bought the car.
when i first tightened the belt, i used a 2x4 and a jack to put pressure upwards on the tensioner and tightened the bolts.

when o started the car i could smell a burning rubber smell and noticed all the "cogs" on the belt were worn down. so i think that was to tight, lol
maybe ill try it again, but put as much pressure on the tensioner this time.

i asked the guy i bought the car from and he confirms that it is supposed to be the 9 psi pulley setup, so even with altitude, im missing ~3 psi.
does anyone know the sizes of the pulleys and what they equate to in boost. that way i can verify my pulley sizes.

thanks

 

I ran it today and watched the boost build up. I was making 4 right around 65 mph. I was getting 5 to 5.5 before the header install. I will measure it when i get time.

 

I think you'll have a hard time making 9psi out of that powerdyne on your setup and also at that altitude. You'll make less boost at altitude. Sounds like your belt was sliping some though. If it was too tight, then i don't think you would have smelled your belt burning up. I would guess that would happen when it's slipping. Have you noticed any belt dust around you pulley/head unit? Usually, from what i've noticed, anytime my belt starts slipping, i start to see dust build up around the head unit close to the pulley. 290hp at the wheels does seem low though for a 383. You should be easily putting more then that down without the charger. Tell us more about your setup if you know. Heads, exhaust setup, tune, injectors ect.

Ken R.

 

from what i can see there was some belt dust around the head unit and around the tensioner, but that was after i over tightened the belt (i didnt look/notice anything prior to that)

here is what i know of the setup:
383, srp/eagle combo
ported stock heads
custom cam (designed for a FI setup)
stock IM
stock headers
3in exhaust
i believe the injectors are stock
and the car is tuned with lt1 edit and also has a fmu on it.

i doubt i will be able to see 9psi, especially with my setup.
i think i should be able to atleast see 6psi or so by redline (~6300-6500ish)


thanks again for all the help,
i will try and tighten the belt today alittle tighter today and see if i can get any more boost out of it.
keep the suggestions coming, hopefully i can get this fixed

thanks again.

 

Make sure you wipe off as much of that belt dust that you can see so you can see if it comes back. It sounds like it was slipping at some point. Also some suggestions if or when you can afford to do it. Bag the stock exhaust manifolds in favor of a decient set of headers. Move up to some 36 or even 42# (to give you room to grow) injectors, get rid of the FMU and retune for the injectors and removal of the FMU. Ford SVO injectors are usually the injector of choice. If your gonna run that turbo in the future, then i'd do the 42's right off the bat. When you were on the dyno, what kind of A/F's was it showing also? Just curious. Also, are you running a bypass valve on the pressure side? If so, you'd want to check that and make sure its closing under boost, or you'll leak boost out of there. And as stated earlier, if your using some kind of flex hose on the intake of the charger, then make sure it's not soft and flimsy. You'd be suprised at how those will actually suck down under boost. If they do then you will not make as much boost. If you must use a flex hose, then try the Vortech stuff. Its still flex hose, but it's pretty stiff stuff and should hold up for your setup for now.

Ken R.

 

When i saw stock header i did this. I would think you would be making more boost with that setup and the restriction. 3" exhaust and those exhaust manifold. Wait till you get some long tubes if you can.