This is on my 87 turbo
I think I have a exhaust leak at where the manifold meets the turbo. I think its just the gasket leaking. what I what to know is would there be any performance loss with a leak there? What about boost? would i see lower boost?

 

Large leaks (ie. quarter inch chunks out of the gasket) will result in noticable (assuming an aftermarket boost guage) decrease in boost. But small (pinhole) leaks will have no effect.

 

what about cracks... my manifold has a hairline crack or 2.

 

If the crack is large enough to leak significant amounts of exhaust gas, then it will effect boost. Start the car from cold, and put your hand over the crack to feel how much is flowing out of it...Be careful, because it'll heat up after about 20 seconds or so.

 

Alrighty yeah last time i was into it i didnt see no cracks, but the gasket was broke. anyone know were to get that gasket other than mazdatrix cause from them its 36 bucks

 

I honestly don't think the cracks are big enough.. especially since they don't go all the way through the manifold.