Stuck diverter valve, I think.
 

I think I am right but I want your opinions. I am not getting full boost. I have the HKS Super Mega Flow Intake. There is a port on each intake that connects to the diverter valve hoses. Out on the race track I would get nothing above about 7psi and it would bleed down to about two. Then I started hearing a hiss every time I was on the power and would not get above 2psi. When I would come in, one of the ports for the diverter valve hose would be popped off the intake. I would re-insert it and go back out with the same result.

If I understand this correctly the only time air should be coming out of those hoses is when I close the throttle under boost and the diverter valve opens and allows the pressurized air into the intake. It should be closed at all other times. My theory is that the valve is stuck open and is allowing boosted air back into the intake all the time until the line comes off and then my boost just goes into the engine compartment and I see almost no boost. To test my theory I pulled both lines off and blew into them. I can blow air through the line that is causing me problems. I can’t blow air through the one that I suspect is operating normal. I shouldn’t be able to blow through either one, right?
Like I said I think I am right but want to know what you think before I spend money on this.

Sounds like a big boost leak to me. Check al your couplers, intercooler piping, etc. Anything to do with what holds boost pressure. G

That's my thought. If I understand the system correctly that diverter valve should be holding the boost in the system but since I can blow air through it, I think it is stuck open.

The functional tests for the parts are here:
http://www.autosportracetech.com/RX-...leshooting.htm

Dave

ralgh,,, u are not completely right,,, u need to study the twin turbo system mate,, i suspect the one you can blow through is the secondary turbo releif valve,,,which should be open until the secondary turbo comes online,,,,try this pull the little vacume pipe of the air valve you can blow through,,, i bet u cant blow through it no more... tell me im right,,,,

Well this is disturbing. I pulled the vacuum line off and was still able to blow through it. I removed the diverter valve, I guess the proper term is charge relief valve. I can see right through it. There is nothing in there. Well there are some jagged looking pieces kind of stuck to the nipple wall. I don't know what one of these things looks like inside normally but I am guessing this isn't it. If pieces did come out of it they would have been injested by the engine. The engine still runs fine but maybe it did damage to the turbo. My brother went to single turbo a while back so maybe he still has his old charge relief valves somewhere. I would like to get this back together and see if I can get normal boost.