HAZ-Matt

Is that really true for all cases of N? So we should all have turbo 1 cylinders?

I think it has to do with the size of the bore and the valves, and so depending on what displacement you choose, one number of cylinders is going to be better than another because the range of bore sizes fits with that number better. This is why all the different engines seem to be sorting into discreet displacement groups depending on number of cylinders.

But I agree that increasing the manifold pressure is always good, whether that be from forced induction or even lowering the vacuum on an NA motor. This is how AFM actually gains anything. Throttle plate has to open more with the reduced displacement of the engine. The only areas that get tricky are keeping EGT high enough post turbo to run the cats properly to meet cold start emissions, and also you need a little more robust knock sensor and ideally wideband O2's.

teal98

If you could get the power you needed out of the 1 cylinder (without shaking the car to pieces)....

80hp out of a turbo 650cc 1 cyl shouldn't be too hard, but what about the shaking? Could this be the next engine for the Smart?