How does a turbo go bad? My tuner can vary the PSI from 0-28 Psi on my Tomei M7960 but tells me my car isn't making any power due to the turbo probably needs a rebuild.

 

Take the turbo intake pipe off and wiggle the compressor shaft. Should be minimal movement.

 

Yes it is minimal ,

 

Did they remove the O2 housing and inspect the turbine wheel?
Does the wheel spin freely with no binding or noise when spun?
No in and out play?

If the turbo is responding to boost control and making more boost but you are not seeing any increase in power then either the turbo is way out of it's efficiency range or there's something wrong on the engine side.

Do you have a cat or test pipe?

 

On the Engine side I have great compression and maybe one is off by 5psi. The turbo has no play but I will have to recheck to see now.

 

Ok I just checked and it has No in or out Play but has maybe 1 MM of up and down play,Very minimal but fins do not touch housing at all. One thing I could maybe think of is the Manifold to turbo has four bolts but one is stripped and just laying there, but I don't believe that she be an issue.

 

Was it you that posted a thread the other day about switching to e-85 and increasing the boost but only obtaining 15hp?

The Tomei turbo is not that large and does not flow a huge amount of air. If everything checks out and you are getting enough fuel sent, then the turbo may just be beyond its efficiency.

 

340WHP is nothing for this Turbo, at E85 an Evo 9 turbo can net you close to 400Whp, this Tomei is bigger then an Evo 9 Turbo. My tuner had my same setup and Made 475whp on E85.

 

I saw your dyno in the other thread, you have very slow boost response as well as low power, kinda looks like a clogged exhaust to me, or cam timing is out.

 

I noticed, I have a straight though exaust system. What I did notice is that out of the four bolts on the exhaust manifold to Turbo bolts one of them is stripped, can it be that?

 

If there is a decent exhaust leak there then yes it could be.

 

It could absolutely be the issue, or at least part of it. At the very least, it's a very easy thing to rule out as an issue. With all the exhaust pressures going through there, it could easily push the gasket in that corner, and cause a leak.

 

Any exhaust leaks pre turbo allow exhaust to escape that would otherwise be powering the turbine. You *should* be able to hear that though if it was significant. Slow response could be leaking wastegate flapper, check the wastegate actuator preload. Could be a a cracked hotside too so check it over. To see if the flapper is seating properly you need to remove the turbo really so just hope it's not that for the minute. Check for boost leaks and check your BOV is not leaking/blowing open. As said already, check exhaust is not blocked, and check mechanical timing is correct (timing belt not out a tooth etc).

 

I checked and I have a nice chunk of air leaving the exhaust manifold to turbo gasket. I can see that a piece hot cracked a punched out and left a 5mm GAP. On idle it blows very nicely, imagine under boost.

 

Mystery solved.