[Supras] New Noise

[Jeff]

I've developed a new noise that is a cross between a sucking sound and a blowing sound (I know - weird). It appears to be coming from the rear of the engine on the drivers side and only when the engine is under load. I'm 99.9% sure it's not in the exhaust system (manifold, downpipe etc). Aside from the noise the car runs great and boost appears to be OK. Anyone have any ideas?

91 turbo

Jeff