Ever since I got the car put back together, I've been having some major engine issues. First it was the timing belt, now it's my boost pressure. I don't hit any boost until around 6500RPM. I've bounced the engine off the rev-limiter a couple of times and it will max out at about 10psi. Keep in mind at a steady 5000RPM I have a reading of 0, sometimes even a vacuum.

Specs:
Evo 6 TME turbo (fresh rebuild)
OEM downpipe
Resonated test pipe
3" HKS catback
560cc injectors
OEM intake w/cone

I've been doing pressure tests for the past week (I've been too busy to build my own, so I've improvised). I found one leak by my EVAP canister which I fixed and another at my throttle body seals. However would leaks like this cause such total boost failure? I know it's not my wastegate actuator, I just recently set the pre-load and the vacuum line was disconnected for my test.

When driving the car pulls and I can hear the turbo spool, I can even hear the blow off valve. The boost gauge I have is fine and works properly, during my leak test it goes up to 25psi.

So the real question is, am I looking at fixing just a few small leaks or is there a bigger problem at hand here? I have a few days until new TB seals arrive, and I would like to pinpoint the issue further. This is my first time working with turbo engines and I have never had the feel for a fully-boosted Evo, as mine has always leaked air. I checked the turbo itself and there is no play whatsoever (rebuilt with under 50 miles) and the compressor blades are good. I have not however checked the exhaust turbine blades.

Also if it is of any help, my car is very quiet. I have a 3" HKS Super Dragger with 2 resonators and a resonated test pipe. Pretty much all I can hear is a little bit of turbo spool, even at WOT. Not sure if that is of any help, but I found it odd.

 

could it be possible that your exhaust manifold is cracked or mani gasket is leaking? it almost sounds like a pre-turbo exhaust leak symptom

 

I was having leaks before, the exhaust coming from the turbo was just insanely loud. I put on a new gasket a few weeks ago and that made everything nice and quiet. That is something to look into though.

 

ive heard stories (never happened first hand thankfully) of cars that cracked the manifold underneath it so it wasnt really loud but it will definitely hurt your spool time dramatically. Think like trying to spool a holset with 2 cylinders.

 

Do you have a boost controller? Seems like a wastegate issue to me. I think you would notice a massive exhaust leak with such a quiet setup.

 

I have a boost controller but I disconnected it for my test. The line to the actuator is plugged and it doesn't open at all, so I know it has nothing to do with that.

 

I unhooked the arm on my wastegate about 7 years ago and it did the same thing, took forever to hit boost and didn't make much when it did.

 

Hook the line from the wastegate right to your j-pipe. If it doesn't hit spring pressure its gotta be the wastegate.

 

Your test won't tell you if exhaust pressure is blowing open the flapper!

 

The flapper isn't moving, it's held closed tightly by the actuator arm. I'll take off the downpipe tomorrow and get a look at the hotside, see if anything looks wrong.

 

Took the downpipe off today and I was able to feel the turbine blades, everything seems in order. Now when I test for boost pressure off of the FPR, I get a reading of about 10psi at redline. Off of the compressor outlet, I get a reading of about 16psi. So I know there is a leak downstream from the turbo, but 16psi at redline is insanely low, considering the wastegate actuator isn't moving.

Would such low pressure from the j-pipe mean that it's directly related to the turbo? Perhaps tomorrow I can remove the O2 housing, what should I check for if it's a faulty flapper? Also would the fact that I recently rebuilt the turbo have something to do with this? Again no play whatsoever in the shaft, all blades look good.