(a) Why is the compression ratio of an SI engine often reduced when the engine is redesigned to be used with a turbocharger? (b) Is brake power increased or decreased? (c) Is thermal efficiency...

(a) Why is the compression ratio of an SI engine often reduced when the engine is redesigned to be used with a turbocharger?

(b) Is brake power increased or decreased?

(c) Is thermal efficiency increased?

(d) Why isn’t reducing the compression ratio as important when a turbocharger is added to a CI engine design?