Odd happenings

[Rob 94Hawk 319]

Okay, so my wifes car is back on the road, mean as ever. It easily eats the 315's in the back now. But I still don't think I'm seeing the type of boost we should be. The car is:

96 Camaro 3.8L w/97 PCM A4 Transmission w/deep pan
Intercooled Powerdyne with JohnD wrap and ASP 2.8" pulley
Closed off EGR port in TB area
Pacesetter coated headers, custom 3" cat-back with new Catco Cat (for having to pass smog).
L67 Injectors
!FMU
!Adjustable Ignition control
Tuned for everything with HP Tuners
3.42's

Most of, if not all of the original piping has been replaced because of the intercooler to stainless steel. Shift points have been moved so the car shifts about 6000 rpms.

Now then, the weird part. With the pulley mentioned above we should be seeing somewhere around 7-9 psi. At low RPMS it shoots up to about 5-6 psi then starts slowly bleeding down til about 3 psi or so as the RPMS raise, I'm pretty sure it should be continuing to build til shift, if not at least hold boost. Now I know the IC is killing some of the boost, (should be about 2-3 psi at most for a 3 core IC), but that doesn't explain where the boost is going.

I was wondering if anyone has witnessed the crank hub spinning on the crank snout? (I'm not sure if it's keyed or not, haven't had to take the crank hub off yet)?

Any ideas?

[Kidcamaro98]

Re: Odd happenings

it sounds like it could be the supercharger belt slipping....its grabbing at low RPMS but as it spins faster, it slips?? just what it sounds like i could be wrong

[Shodown]

Re: Odd happenings

I dont think its slipping cuz he has the JohnD wrap. I would get it on a dyno, do a few pulls and see if you are leaking air somewhere causing you to lose boost.

[Mighty Thor]

Re: Odd happenings

You got me that one. Usually with the Centrifugal SC boost raises along with the RPM.

Where is it in gears when it drops?

[ssms5411]

Re: Odd happenings

thats the same problem I had when I had a intercooler on mine . I lost at least 3 psi running a intercooler and it was also hard on the supercharger head unit.I think it put alot more stress on the internal belt as well. I later took off the intercooler and put on a methanol injection setup.i was running a 2.9" pulley at that time and was seeing 5 psi , i went to a 2.6" pulley later on. good luck, Steve

[Rob 94Hawk 319]

Re: Odd happenings

I'm thinking that it might be slipping a little, but it doesn't exhibit that type of symptom (erratic boost). I'm thinking maybe the crank hub might be spinning, but haven't had time to take the hub off to check.

Mighty Thor, it happens pretty much in every gear, of course in the longer gears, it takes a little longer to bleed down.

ssms5411, I'm thinking that maybe the Powerdyne head unit isn't efficient enough to handle a 3 row intercooler, and on higher boost it's just bleeding back into the impeller.

[Mighty Thor]

Re: Odd happenings

Try running the SC without the Intercooler and see if it does that. I don't have a personal experience with intercooler just water/alcohol injection. Perhaps it may be too restrictive.

Do you have pics of the set up. Kinda interested on what your set up look like.

[Rob 94Hawk 319]

Re: Odd happenings

I'll grab some tomorrow, the car is at the house today.