I just hope your able to get this all dialed in and doesn't end up something costing too much $. or any $ for that matter. lol

Yes just connecting to the turbo it is supposed to test everything however I always have slight leakage through some of the intake valves. If my logic is correct in my mind lol There will always be one cylinder in the intake stroke (ie intake valves open) so always be a leak without loosening the rocker arms in order to close them all correct?

Interested to see how that goes.

Yea that is true if you do undo the 12s on the intake rocker arm the valves will close , but if you just do it the reg way it will also let you know if anything is leaking by being able to hear any kind of leaks . By undoing the rocker arm you would also be checking the intake side of the valves which could also leak slightly if the head needs a valve job .

Yup thought i try it since the car did break a ringland on piston two racing a c5 z06 and not paying attention to the gauges and overboosted slightly .

Any luck on figuring things out yet 03Lances?

Not yet, have been thinking though. Any of you turbo guys get pressure through the valve cover vent when doing a boost leak test? I am pretty sure I always have but I wonder if my valve seals are getting weak . Have to finish up some thing for a class final then I plan on getting back on this.

Well I was able to isolate the intake manifold and test it. Nothing major, I do think my manifold gasket itself may be ever so slightly leaking but not nearly enough to cause my current issue. I was wiggling my injectors to check those and when I fired it up after testing I had gas going everywhere . It was like a hose that you didnt put a gasket in hoping it would hold lol. Found the #1 injector o ring had torn into 2 separate pieces, luckily I had a spare and fixed it fairly quick. I zip tied as many hoses as I could get to just as a precaution but I am guessing I will have the same problem. Idk maybe my turbo is fried but how would I tell? Shaft was fine free spining and no play. Spool hasn't been this good in awhile since I solved the wastgate issue
I do still have the original stock wastegate maybe I should try it idk. From what I understand the wg is acutally only 11-12 psi but then there are "boost pills" added to the line to increase the pressure to 18 for the evos

Honestly when you first brought this up and mentioned you found out the wastegate had a little flap to it, that really makes me think its what was allowing you MBC to show gradual increase when adjusting it. Kinda like if you had a garden hose with a good size hole in it back in the line somewhere and were slowly opening the nozzle and were getting a slow increase in water pressure but not extreme. then you fix the hole and you notice the next time you go to adjust the nozzle from closed you have a sudden increase of water pressure. Just a thought I was having. You could have been running 9 to 10 psi this whole time with the MBC allowing it to increase to 15 simply cause it was that even flow. With the Flap fixed. That MBC has no middle ground. Its either open with easy boost or hard at 18psi. Again this was just my thoughts on this.

I could see this if I didnt feel a dramatic loss in power vs when I was hitting 15 psi. Considering I am not tuned for 9-10 psi anymore I would be willing to bet I am down 50whp or more. I can say for sure I was hitting higher boost than now. with the turbo clocked like it was before I had the wastegate rod adjusted all the way down and it was still slightly too long causing the door inside the hotside to remain slightly open. I never realized this as the last couple times I pulled my turbo off I only pulled the coldside so I would not have to deal with pulling the radiator and manifold etc. It seems ok untill I pulled everything this time and found the issue for sure.

I am hesistant to say the wastegate is causing the issue as from what I have seen all this wastegate is, is a rod that is held by a spring and a boost source that will build pressure inside the chamber causing the spring to compress which then allows the door to open letting exhaust gases bypass the turbine slowing the turbo down to keep boost at a certain level. Only thing I could see failing would be the spring loosing tension which would cause low boost but I have already replaced that with no change. If the gasket in the wastgate failed I would think this would cause increased boost pressure as the pressure used to compress the spring would be lessened causing the door to not open enough. Debating pulling off the boost source line and doing a quick run I am guessing it should overboost assuming everything else was fine.

How you just explained it makes sense as well. Too many possibilities it seems. lol

Only problem is i've eliminated several of those possiblities lol I might do a comp test for the hell of it this weekend just to see what I am getting.

I have pressure coming out my valve cover during boost test like you, depending on where my pistons stop i think.

Is your turbo toast?

Upgrade time? get an evo ecu, swap those 2 wires, add another to a gm3port on the "wastegate solenoid" spot, and then run power from a fuse to the 3port. Tune for 16psi! Then you get to run 16 during spool, and by redline closer to 18-19psi, just keep torque where it's at during your spike and it ought to be fine, right?

Man I hope not and I dont see how it could be it spools hella quick after fixing that little flapper door issue it just spools straight to 9 psi in the blink of an eye and is abruptly held up. I bought a new fitting for my compressor that will allow me to connect in to my car without having to hold it on there. I am then going to set the regulator to around 15 psi and I made a checklist as where boost leaks could be hiding lol. That way I can have a constant stream and locate all of them without having to run back and forth. I havent had a chance to swap out my wga with the stock evo one yet that will be the next thing I try. As far as your suggestion goes in theory should work great just cutting back on timing around peak torque to avoid blowing her up lol. Couple problems there is

1. Already have traction issues during spoolup lol
2. A torque spike running that much psi I imagine would make for a really crappy day haha

The only reason the leaks from the valve cover is because you still recirculate your Pvc from your intake manifold , no biggy . I still thing it has something to do with the Mbc or Wg .

I'm thinking the same thing