Still not making full boost

[Ronin]

So a quick recap since I've been quiet for a while.

Bought 96 GT with Procharger P1SC already installed with 12 PSI pulley.
Time went on and I started noticing it wasn't hitting full boost any more. Was hitting about 10 PSI. Started dropping. Got a CEL that it was running lean.
Was only hitting about 6 PSI (and then creeping from there) when I took it to the shop. Had the shop remove the Diablo chip and put in and tune their own chip, CEL gone. Had them put an 8 PSI pulley on since 12 seemed a bit too much. Replaced rear seal on P1SC, the belt (was missing a full tooth), and another squeaky pulley. Shop tells me it's still only hitting about 6 PSI because of too much back pressure caused by stock cats (6 of em).

I now have a Pypes X pipe (O/R) in place. Pressure is still around 4-6 (followed by creep). P1SC is not making any peculiar noise (just that beautiful whistle at idle).

When I had it in to have the chip/pulleys/etc. done, they also mentioned that the IM, though still working, will probably need replacing soon. Is it possible that a leak at the IM would create a limit in boost? I'm grasping at straws here, everything else seems good.

 

[vermilion]

underdrive pulleys? remove those if you have them. underdrives slow down the boost pulleys. any boost leaks or strange bends in tubing? are you running an intercooler?

 

[Ronin]

All the pulleys are stock. I imagine it is a leak somewhere, I just don't have time to go hunting for it. I am running an IC.

 

[duff daddy]

not really 2v specific, moved to fi

 

[vermilion]

if it were my car id be searching for it. lean conditions are not to be dealt with lightly.

 

[Ronin]

It's not lean anymore. That was several months ago and was solved by the new chip and tune. I'm just dealing with low boost at the moment.

 

[Ronin]

interesting note, I hit 8 PSI this morning in first...shifted to 2nd and couldn't get past about 5 PSI.

 

[JDwhite98gt]

I'm no FI guy but are you sure you arent getting any belt slip? Arent prochargers run with a bypass/blow off valve? Could it be sticking open? I wouldn't take a leaking IM lightly, if its leaking then there goes your boost. Are you sure the headunit itself is ok? Maybe time for a rebuild?

 

[5litrarag]

I'd think the bypass valve is fubar...

 

[Ronin]

I'd think the bypass valve is fubar...

I'm not so sure, it was fairly recently replaced. Was making a really odd sound before, and it's making it's typical pssshh sound now.

 

[snoball]

Sounds like the bypass valve is either stuck open or just a junk unit. Look into a metal bosch unit. Other than that, check the vaccuum line on the bypass for a leak.

 

[Ronin]

assuming it is the bypass valve, this is what i have now (replaced 4 months ago)
http://www.superchargersonline.com/product_detail.asp?PartNumber=PC-AV005A-001

Is this the Bosch unit you're talking about?
http://www.superchargersonline.com/product_detail.asp?partnumber=SODC-BP1&tabactive=1

That looks plastic and a lot cheaper...Sounds like some people swear by the red race valve, but I just spent $700 on a diff/gear/rear end rebuild (plus a new wheel bearing). What horrendous fate could I expect if I put this off for 6 months?

 

[snoball]

http://www.superchargersonline.com/product_detail.asp?PartNumber=SODC-BP-RACE

Metal.

But you wont suffer too much besides have a slow s/c car. If i put a blower on and only made half or less than half of what its suppose to make Id be trying to fix it asap.