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But what's the BSFC for an engine at part throttle? I still haven't seen a good explanation of this aspect of engine/drivetrain design. My gut tells me it's not reasonable to say that because my 340 has it's peak torque at 4000, I should set my highway cruise at 4000rpm for best mileage. Somehow a 400hp Corvette can pull mid-high 20's on the highway while turning maybe 1500rpm. Torque peak on a Z06 sure isn't below 2Krpm. Until I can sort out how VE relates to a throttled situation, I'll stick to thinking that best economy is going to come at the lowest possible engine speed that you have good fuel control.


Clair


Lower RPM flows less fuel, yes, but if the engine happened to be at it's peak torque at the speed you were driving at, it would get better gas mileage. Lets say two similar cars were driving at 60 MPH and at the same RPM. One car was at it's torque peak and the other was under it. The one at it's torque peak would get better mileage. Now they both accelerate to 90 MPH. One car is above it's torque peak, and the other is at it's torque peak. The one at it's torque peak is now getting better mileage than the other car. We have much more to consider in reality than just BSFC and torque peak, but it is one of the many factors.