small boost leak?
 

So when I first installed the PFC and Commander I found myself getting about .2-.4max bar of boost, even my crappy autometer gauge was showing a pretty bad reading. So I read the FAQs and such and found my Y-pipe coupler riped in about 3 places and hardly in one piece. My car has made a hissing noise like crazy ever since I've owned it, I thought that was the spooling of the turbos, but it was actually air blasting through the coupler. So I fixed it and a fantastic .75bar boost made the drive great! It was like getting a new car actually. .75 wasnt the .8 the PFC is set at but it was hella close and for 135k miles on the twins I was happy. So with this new pressure back the way it should be a couple other couplers were a little lose and popped off, but I retightened them and all is well. Well now it seems theres a very very small hissing noise when spooling, and im only getting about .65bar of boost, but my autometer is reading perfect 10-8-10, WTF. What should I trust, the 30 dollar gauge or the 700 dollar ECU....hmmmm. The tubing to the gauge was shitty and broke so a while back I redid about half of it, and patched the two together. Could a bad boost gauge line be causing this small loss or something else? I know .1 bar isnt THAT much but it still makes a difference and now that I know how the car should run and how fast it should be, I want it that way! Any help...helps. Thanks

Go through and pull off all the IC couplers and turn them inside out. This will usually make little tears your wouldnt normally see appear. Its possibly for there to be a small leak but the turbos can still overpower it and produce a perfect boost pattern. If your hearing a hiss thats what is most likely is.

Ill go ahead and do that once she cools a little more. I just tested boost at WOT in neutral and got 3.4psi, which I guess is an obvious sign of a leak.

WOT in neutral should only produce 3-5psi.

It sounds like you have another leak (check the elbow at the bottom of the i/c, make sure to remove the metal covers).

I would trust the PFC reading more than the autometer. Most mechanical gauges are only good to 5% or so, and Autometers can sometimes lose zero and be off by more than that. The PFC relies on the MAP sensor, which usually doesn't lose calibration.

Dave