[mikuni]

Originally Posted by JamesH

Something doesn't quite make ense in that video (probalby just me). Towards the end, MB talks about moving the very hot compressor to the front of the car. I always thought it was the turbine that was hot, being in the exhaust flow. Admittedly compressing air does create heat, but not as much as the heat as in the turbine. The statement also contradicts the original premise that moving the compressor to the front means less heat and less intercooler needs.

Clearly, with the compressor at the front, they do have lots more scope for a compact rear end, which is what he was getting at. It just the statement 'very hot compressor' that seems odd.

Or have I completely misunderstood (it has happened before)?

I agree with what you're saying regarding the heat, but the principle still makes sense - in fact, it makes more sense having the hot bit at the back, separated from the part you want to keep cool, in the inlet tract, at the front.

Here something some left field.

Given the shaft from turbine to compressor runs through the engine, I wonder if there is anything to be gained from being able to use that rotational energy, or perhaps use oil flow to maintain shaft rotation to keep the turbo up to speed. (Or perhaps it doesn't actually run through the oil path). One could imagine being able to use the oil flow (if fast enough - I presume the shaft is rotating at extremely high RPM) past the shaft to maintain its velocity. Almost like another turbine powered by the oil flow.

Hmm, having thought about it whilst writing, I feel the oil flow, even if jetted through a small orifice at high pressure, wouldn't be fast enough.

Back to the drawing board.

I'm sure it will be in the 'V' of the engine and be 'dry' from lubrication, other than lubricating the bearings of the shaft. I don't see any advantage to immersing it in the block, or trying to spin it up with oil pressure. That is already doing a very important job and you'd want to keep as little additional heat from the oil as possible while trying to moderate core engine temperatures.