downhill on gear fuel consumption

[HummerJim]

Originally Posted by Hammer

I should have added is it normal ? my brand new z06 corvette does not or neither does my bmw m6 . btw my m6 gets worse mileage than my hummer

My M5 gets about 2 mpg better than my H2 and is the most economical of the cars I own. When you factor in insurance and depreciation, fuel would only be my primary consideration in ownersip of a vehicle if I drove over 24,000 miles a year, but to me vehicles aren't just transportatioin, they're my passion and hobby. We are lucky in the US to have reasonably priced gas in comparison to Europe and other parts of the world@
Fuel consumption on an engine is determined by load and RPM, temperature and air density. Take our home emergency generator for instance - under a 15Kw load it will consume around 4 gallons per hour at 2200 rpm, while at 1 Kw at 2200 RPM it will consume about 1 gallon per hour. Same with a boat engine it's almost always under load and rarely coasts, so they consume a lot of gas and wear out fast. We had an ultra miler on the forum in 2006 - He would tailgate semis, coast downhill with the engine off, run ridiculoulsy high tire pressure and got over 20 mpg with his H2. If you want economy, buy a Prius I always have said.