Just wondering what the difference is between turbos (std or aftermarket) on a Impreza and single turbos on an RX7 or Skyline or similar.

Is it a different entry to the turbo (90 degree)? Tried searching for this, but couldn't seem to find the answer, just vague bits that make me think that this is the difference. Can this be worked around with a different manifold?

 

Erm, different turbos are different physical shapes, period. Earlier Impreza turbos have 90 degree inlets, later ones are front entry. The exhaust housing on Subaru turbos is quite specific IIRC, and isn't used on any other car to the best of my current knowledge. Also have to remember that some are designed to spin clockwise, and others anticlockwise.

Thus, you probably could, for the sake of example, adapt a Skyline or RX-7 turbo to fit an Impreza via customised inlet and exhaust pipework, but, with a wide range of units available both complete and in hybrid form to fit straight on an Impreza, why on earth would you want/need to?

 

I had a To4R available to me, and just wondered if there was a major reason why it wouldn't fit - something like a 90 degree entry that would cost a fair bit to adapt - or not.

Which you've answered