[Gasoline Fumes]

I've been giving this some thought lately. Keep in mind that these are my thoughts/theories, and are not based on any testing. A heavier flywheel makes engaging the clutch easier and probably stores a bit of energy to get the car moving that would otherwise come from extra fuel. But once the clutch is engaged, I think the flywheel is just making the engine work harder and use more fuel while accelerating. If you "pulse and glide," you'll never recover the energy used to accelerate the flywheel. I can't imagine flywheel weight having much effect on the highway. Unless I was doing a lot of stop-and-go driving in hilly areas, or a lot of towing, I'd try to get rid of as much flywheel weight as possible. Which is what I plan to do with the CRXFi.