Turbo CHRA leaking?
 

Ok so I'm trying to put my car back together, and I'm stumped. I have the ETD manifold with a new gasket to the head, AND a new gasket between the turbo. I have a new gasket between the turbo and downpipe. So basically this thing shouldn't be leaking at all.

But it is. I can't figure out how the hell it can still leak. I took the hotside housing off the turbo to install some helicoils. When I took it apart I needed a hammer and some light force to get it apart. Now that I put it back together it just falls out. There is a small space between the CHRA face and the hotside housing face, maybe 1/32". My only guess at this point is that the CHRA is leaking between there. Are those two surfaces supposed to touch? If so how the hell do you get them together?

I took it for a quick drive and it has very poor throttle response, if I give it any throttle when cold it stalls, and it makes the fluttering sound of a bad gasket...but they are all new with 0 miles on them.

What the hell is leaking?

A turbo with an exhaust leak would NOT, ever, cause a car to stall. Sound like you have other issues. Fluttering sounds like you have a wheel possibly making contact with a housing.

Well keep in mind that the leak is before the wideband, so I'd imagine it will mess with things. The fluttering is for sure air leaking. I made sure to spin the turbo by hand before starting it and the blades never touch the housing at all.

Unless you are running some sort of closed loop fueling, which i can all but guarantee you are not, then the WB will have zero affect on your motor running. All the leak might possibly do it make your wb read lean. However it will only show it in a log, it will not affect your current open loop fuel and ign maps.

Check for a vacuum leak. That would cause your map sensor reading to be off which would have the exact affect that you are experiencing. A vac leak would cause you to run rich and throttle response would suck.

Thanks for the help, I still don't know how to use the software side of megasquirt that much. I really need to learn.

Anyway, I found the leak. As I suspected when I saw the manifold it leaks through the bolts that go into the runners. I started it and really quickly sprayed a little water on the bolts, lots of bubbles. I don't know how such a small leak can be so loud.

Now, how do I seal the threads? Copper washer? I guess I'll email ETD and find out. Seems like a really stupid design.

I had a chance to look further into it today. When I rev the engine the exhaust comes out of the 2 bolts that were open to the runners. The air comes out so fast the turbo slows down a lot, and the sound comes from under the CHRA area. I'm guessing the turbo slowing down is why it has poor response and wants to stall. Once it heats up it doesn't stall, but it sputters a bit.

I'm thinking of using some copper RTV on the threads. Either that or some heavy grease. Anyone else know how to seal the threads? Searching just told me to use the copper RTV, but that was for NA engines and not turbo.