lol... Bob

 

If you decide to put compressed air into the system keep in mind a couple things.

Remove the bypass valve and stop up the hose. The bypass valve is like a throttle plate and isn't designed to seal tight, or it might stick in the bore. The leakage around the blade is minimal to a flowing system and won't affect power if the diaphragm works properly.

Second don't get crazy with the air pressure. 15 psi is plenty. You could damage your intercooler(s) with 60 psi.

 

actually you should do just the opposit. Leave the BOV on there with all lines attached. that will tell you if the BOV is cracking open under boost. If its the adjustable kind you can then set the pre-load on the diafram so it stays shut and you don't lose any boost.

 

Now just how are you proposing to do that? You can't hook compressed air to the attached intake manifold and engine because you are going to lose the air out of an open exhaust valve during overlap or past the rings so the diaphragm won't see "boost".

The area of the diaphragm is greater than the valve so boost pressure holds it closed. The spring is just there to bias the valve closed. You could run the car without the spring at all.

 

You don't need to hook air up to anything except the compressor inlet. The intake manifold will fill up on its own and you will be able to tell if there are any leaks between it and the head(s). Trust me it works. I've done it literally hundreds of times on many different different cars.

If you start removing components and plugging VAC lines and stuff you completly defeat the purpose of doing the test in the first place. Leave everything attached and make sure its VERY quite so you can listen for air excaping from everywhere.

 

Are you taking these boost readings at redline? I read that you are "untuned". You should only get full boost at redline but if your reading it at say 3500rpm -of course it's low.

 

Yes, these readings are at redline.

 

Alright guys, figured out my problem (and yes I feel like a D/A). The plenum I had made has about 20 pin sized holes in it. The guy who made it for me didn't tell me he couldn't TIG weld (yes, he wire welded it). Anyway, we did the boost Pressure test and were getting really frustrated with it because we couldn't find any leaking pipes. Right before we called it quit's I stuck my hand on the Radiator and felt the air blowing from the Plenum. So there is my problem, shouldnt had made it this long without checking it but I guess I was just looking for a "complex" solution when it shouldnt been one of the first things I checked.

That being said, DOES ANYONE HAVE A METAL PROCHARGER PLENUM THEY ARE LOOKING TO GET RID OF?!!

 

Glad you got it figured out. amazing how a bunch of pin holes can rob you of that much power huh.

what I've done in the past, depending on how **** you are about looks and what kind of time frame you're working with, is dab some JB weld on the pin holes. I've tested that stuff upto 30psi with no problems.

 

alwaysinboost, who would have known those pesky pin hole could screw me over like that lol. Thanks for the JB Weld Idea but Im just going to give the box back to my friend and Buy a Metal Procharger Plenum...I know someone has one they arent using.

Thanks again for the help guys!
Blake

 

I hate to say this, but I don't think that's going to be your problem. Pinholes that you described aren't going to cost you big power. There's a big difference between pressurizing your system with air from a shop compressor and a flowing system from a supercharger. Good luck in your quest, but I'd keep looking just in case.

 

Some of the holes were larger than the others...It was a noticeable amount of air coming from the Plenum. Who knows, that might not be the problem. But I'm going to get another Plenum just in case. No Hoses were leaking, bov works, and filter is fine. Kind-of my last resort.

 

Really, whats the 'big' difference?

15psi is 15psi as far as I know...

 

Ok, the 'big' difference is that your average shop compressor might make 10-15 cfm @ 15 psi and the system isn't flowing air, while the supercharger might make 1100 cfm to make that same pressure while the engine is consuming air. Losing a few cfm out of small pinholes isn't really significant when you talking about hundreds of cfm going into the system.

 

I had the same problem on my truck and my impeller shaft snapped.

 

don't take this the wrong way but I think your confusing volume with pressure.

the CFM a compressor puts out doesn't matter because you aren't trying to see how much air the engine can move. All that matters when doing a boost leak test is the pressure your setup can hold w/o leaking.

the "amount" of air flowing thru the engine is a function of many different things but in a nut shell the more efficent the engine the greater the CFM the engine will move and with less pressure behind it.

 

I'm not confused, you're just not seeing the point I'm trying to make.

Small leaks may keep a compressor from maintaining a test pressure in the system when its sitting there static but that doesn't mean you've lost any significant airflow wnen the engine is running.

Testing the system statically may help find a problem that may have been missed otherwise, but in the grand scheme of things small leaks aren't relevant.

While a shop compressor may only be able to maintain say 12 psi on a tested system its quite reaonable that when the engine is running it may be good to well over 20 psi.

Street bypass valves and volutes for instance don't "seal" per se, but the airflow lost doesn't affect performance due to the overall mass of air going through the system.

 

I'm honestly 100 percent lost in "andereck" and "alwaysinboost" conversation. But the point I was trying to make is. We basically tried EVERYTHING under the sun before doing the "pressure test". We capped off the 90* Hose going into the Supercharger so that no air could escape through there and hit the lines with a good amount of air. So basically the air had nowhere to go unless there was a leak. Sure enough I think we found the problem. I may not be right but I don't know what else it could be at this point. The only thing I know to do is replace the Plenum with a Procharger Aluminum plenum and try er' out.

Still looking for a Plenum BTW

Blake

 

Sorry if I've muddied the water. I felt it was relevant. I should have just said, "don't sweat the small stuff." I'm not suggesting sloppiness, or carelessness, everything adds up but I think that many don't consider the incredible amount of air we're dealing with.

 

I second you on that fact those tiny leaks In my eyes are not going to creat that much of a boost loose...

Did you install this cam before or just now that you have a boost loose? Some cams if not designed just right can also cause boost to leak off through the exhaust... What is EPP's cam specs?