I am unsure, but I am going to replace my blower belt anyway.

I have a 8# P1SC

Symptom Description:

The car runs completely normal in vacuum mode (non-boost).

Normally, as I accelerate with full acceleration (2nd gear) I see boost come on with about 1# at 2000 RPM. As RPM rises, boost will rise to about 7# by about 5500 RPM.

However, in this situation, what I am experiencing is that my boost gets to about 2-3# at about 3500 RPM, then flutters and then I notice my boost drop below 0 and and then I have vacuum. All the while I am in WOT. Needless to add, but the car really runs crappy while accelerating into boost territory.

I am thinking that my belt is slipping. Are those the symptoms?

My logic is saying that as boost increases (with RPM) the blower is putting a lot of drag on the belt and when it begins to slip, it then produces less air than is necessary for normal aspiration and actually becomes a point of restriction. As boost drops to 0, the recirculation valve then kicks in and the car is sucking what it can through a 2" hose.

 

It could be detonation or the spark getting blown out. If you get too much detonation or lose spark, the engine can slow down long enough to open up the bypass valve.

 

Had the shop replace the belt. But, that didn't fix anything....

Hmmm.

Maybe it is a spark issue.

 

Your bypass valve is either not hooked up properly or the diaphragm may be ruptured.

 

Has it run perfect since the install letting you get to 7 psi? Did you do anything since it started running this way? I used a tire iron and wedged it against the payment and tapped the bottom till it was as tight as can be. No problems now plus i had the fmu hooked up wrong that caused as sorts of problem. Does your fuel pressure continue to climb the whole time? Whats your plug gap?

 

sounds like somthing in the intake track is collapseing.. your using that POS dryer hose or somthing along those lines? might wanna start there

 

If you are suspecting it is belt slippage, just get a tensioner. That will take care of your problem.

 

I am 99% sure my problem is a blown P1SC.

I moved my MAF to the intake elbow and the car ran like a N/A car. No RPM hesitation throughout the entire RPM range.

I then checked the output of the blower while the engine was spinning it and it was producing decent pressure at idle. But as I rev'd it up to about 3000, the blower completely stopped putting out any air whatsoever.

So now it has to come off and I get to send it to ATI for a rebuild. I had just turned over 50,000 miles on it.


Feels funny driving a N/A car. It runs real smooth, but no more seat-planting experiences during acceleration. It feels like it's got about 320 hp. Since I'm running 9.0:1 compression, I might just put a tank of regular unleaded in there until I fix the P1SC.

 

Na, I think you need to look at the inlet hose as 30thTA0525 suggested. There really isn't anything that could happen to the blower if it works fine at low rpm.

 

I have that flimsy orange intake hose. I did look at it and it seemed normal and all (other than being filthy and soaked with oil drippings). I could just remove it and see if that makes a difference. Sure would be a simple problem to fix, instead of removing the whole enchilada. Procharger has dumped that intake hose for a solid plastic unit on their current models.

I might just check that out...

 

Did you try tighting the belt as much as possible. I can't think of why the blower would work fine and the go out at higher rpm unless there is slippage. You should have almost no play in it at all. Mine feels like a rock and works great.

 

Usually a symptom of belt slip is flatlining of boost. Boost will rise and then just flatline as rpm rises. The orange intake hose usually isn't any trouble at 8 psi on a stock engine. The trouble is that as the filter gets dirty it increases in restriction. Eventually the restriction increases to the point where it can collapse the hose from vacuum.
You really have to stay on top of filter service with a blower. It just flat filters more air than a n/a application due to the flowrate.

 

UPDATE:

Okay, I've been out of town a couple of weeks and the SS has been in the garage.

I sensed that I had another, simpler, problem... Sure enough.

Apparently, after 50,000 miles on the P1SC, the orange flexi hose that connects to the intake port of the P1SC was collapsing internally. After removing it, the coil wires had separated from the rest of the fabric and as boost increased it simply collapsed and sucked into itself.

The head-unit itself is fine. I have ordered the new style plastic inlet assembly. Unfortunately, Procharger's new arrangement is for a push-through MAF instead of draw-through and the hoses and other connections are going to be a bit of a kluge setup.

Has anyone used the new plastic inlet assembly with a draw-through MAF arrangement? I hope I have all of the parts. I'd like to go with the push-through MAF setup, but the additional parts are out of bounds on my budget for now.


After driving around on N/A for a while, I sure miss the power!

 

I had the new plastic inlet tube on my D1SC. I was only seeing 9#'s of boost while it was on the dyno. I later tried going to a larger inlet tube only to have it collapse on me as well . I ended up putting the stock plastic inlet tube back on with a larger air filter, and I ended up seeing the same boost #'s I saw on the dyno with no filter on it . Over this winter, I have ended up getting a metal tube that I will be installing in place of the plastic one from ATI. Depending on your boost, you'll probably be fine with ATI's new plastic tube (probably if you are running under 10#'s)

Here's a pic of my new metal tube;



And here's a video of me at the track with the inlet tube that was collapsing. The first run, I just stayed in the throttle even though it was collapsing, and getting me like 4-6#'s of boost. The second run the boost ran great until it was under more of a load when I put it in 3rd, and it collapsed it so bad I let off the gas all together.

Click here to see Video

 

That sure looks like the trick! If you're collapsing piping and hoses, you can bet you're not alone.

We might want to enlist a good fabricator for all of our needs.