Originally Posted by Alex07M3
I wonder why they replace the V8 for a 6cyl since, like you said earlier, they could've easily made that engine more fuel efficient by working a bit more on it instead of dropping the ball like you said they did!
I personally have no cogent advice for BMW as to engine modifications for better fuel mileage, but have suggested overdrive gearing for better highway mileage. If pressed, I would tend to think that engine mods sufficient to significantly improve mileage would mess up that more or less peerless torque curve, which would be criminal, in my opinion.
Dropping the final drive ratio to somewhere between current and 335 gearing would improve overall mileage, but would affect off the line performance to some extent. Not a bunch, though, since the current car is essentially traction limited in first gear.