New mercury 4 stroke fuel economy

[SilverFox579]

Wonder why the OP hasn't been back...

[lpugh]

Four strokes have a much higher Pumping Loss than Two strokes, Optimax motors have almost no pumping loss other than the compressor and that is negated in the fuel charging. If pumping loss were equal to a two stroke it would do much better. I do not think many realize what a engineering master piece the optimax motor is,

[lpugh]

More cubes and 2 more cylinders to feed i could see where they could burn a little more especially at wot. All ive ever owned are v8s in my vehicles and i dont own them for their fuel mileage lol

But the four strokes only have a average working displacement of 2.3 L vs 3.0L for a two stroke, this is where pumping loss and friction come into play as well as power consumed to operate the valve train which is substantial. The actual air/fuel ratio I think would be very close to the same for emission purposes
I see feedback fuel control, variable valve timing and possibly variable intake runner length with in 10 years on these new motors...….

[BMCD]

3.0l was the Optimax 200hp+ Block. The new v8s are 4.6l.