This is my TD04HL 15G (conical flange) Turbo looking into the turbine housing. There is a crack running through the waste gate lip.

I do not get full boost pressure anymore.

I have read that this is a common crack and people do not worry about it.

Should I assume this is my boost problem or not? Is anyone else familiar with this problem?

thanks

 

What does it look like on the outside of the housing ??

 

The outside of the housing is intact. The crack is positioned where it may be letting exhaust gas past the waste gate. The question is, is it big enough to cause a noticeable drop in pressure? Here is another picture from the other side (you can see the crack on the lip where the waste gate sits).

 

How much pressure loss are you experiencing? I wouldnt think its big enough to cause a real noticable difference.. did you noticed this drop in pressure overnight or overtime? Is it boost fade, lag, fluctuation? Maybe check for leaks first.

 

Can you take a picture of the top by where the rod attaches?
The shaft walks up at times. That causes the flap to not seal causing boost loss.

 

Here is a picture of one that walked up. The arrow is pointing to the gap it should not have. Also this is not my pic. Someone posted it a while ago and I added the arrow to show what was wrong.

 

I'm just guessing but that doesn't look like it would bleed off much air. For what little volume of air might get through I wouldn't think you'd lose noticeable pressure.

 

Mine on my Yellow was like that at one time. It was a 5 PSI loss.

 

Mine had that too. I was pretty pissed when I bought it and the previous owner thought it was nothing. I dont know if it affects the boost. Theoretically if the gap heats it will expand and let exhaust through which will bypass the turbine. I have since purchased a non cracked version.

 

How high were you running yours at the time ??

 

At the time I was running about 10 PSI when it slid up. But it only happens with the conical setups for some reason.

 

Sorry to be a pest but are you saying it dropped 5psi off of stock (9-10) or you were running 15 and it dropped 5 ??

Do you think you dropped the pressure from the crack or from the relief valve shaft moving off the seat ??

 

Was running stock 10PSI. It was from the shaft moving up. I had taken a hammer and tapped the shaft back down and all was good.

 

Seriously an overnight loss of about 1/3 boost from running stock pressure.

I don't see any movement of the waste gate flap. I think I will just replace it...