I can say that it was definitely quieter, less smoke on start-up. Seat of the pants meter seemed to be the same as to power. Mileage around town went from high 13 mpg to 17. 5. Our town is a country town, no red lights, country roads you can drive at 50 to get into 4 lock. Highway unchanged at 21mpg@ 67 mph, empty except for skinny wife and 55 lb pup. (german shorthair)