The tricks up my sleeve... Methods I may implement for better FE.

[landspeed]

Originally Posted by omgwtfbyobbq

That's the great part about the EPA highway test. It's consistent! So, given the same car, one with a NA engine, and another with a turbocharged version of the same engine and a taller transmission, on the same test. It's evident imo, that the turbocharged engine is less efficient than the NA engine if it gets worse mileage, because it's over the same test, in the same car, with the same engine, and a slightly more efficient transmission ratio. The only variable I can think of would be the ECU, but I'm pretty sure that's the same for both, since all cars have to keep the AFR at 14.7:1 during normal driving unless they're lean burn, diesel, or hybrid iirc. .....

I would say two other reasons are, that turbo engines (at least mine) might enrich the fuel mixture at a lesser throttle than a NA engine, presumably because if you go on full boost, the engine heats up inside, and then cruise at part throttle, it might detonate due to the extra heat that you wouldn't get in a NA engine.

Also, turbo versions of engines generally have a lower compression ratio, again making the engine less efficient. Diesels have an extremely high compression ratio.

My car has a lot of torque at about 2000RPM, but, below 1400rpm, there is very little torque at all. The newer 2.0 16v high compression engine (mine is 1.8 8v low comp) is so different; if you just touch the accelerator slightly at 1000rpm, you can feel the power of the engine, and the car will begin to speed up if on a straight or slight downhill. Even the 1.0 Nissan Micra/March 16v engine is like this - a lot of torque low down. With my car, I need to keep the revs at 1500rpm minimum, in order to accelerate at all.