Not exactly sure how to calculate it, but if I use some *rough* estimates, this is what I come up with:
Assuming 24mpg to maintain 60MPH and 1/2 gal per hour to maintain idle. Drive for 1 hour and you would use 2.5 gallons (no coasting). If you can coast for 25% of that in neutral (15 minutes), you would consume 2 gallons (1.875 + .125 for idle) (30mpg). If you can do the same coast in gear, you would consume 1.875 gallons. (32mpg) 30MPG is about right for steady 60mph, which is about 2 gallons per hour at 60mph. Of course, this "math" all depends on the underlying assumptions which are a SWAG. Ideally, if I could communte downhill both ways, I suspect I could attain 50MPG or more... KEN On Mon, Jun 16, 2008 at 12:48 PM, Aleksandr Milewski <[EMAIL PROTECTED]> wrote: > Bill Cardell wrote: >> Does the slowing from the wheels >> driving the car (which then has to re-accelerate more than if the car >> coasted) outweigh shutting off the fuel? > > I have to believe that the losses from running that big air pump from > the wheels far outweigh the fuel burned idling. I have a 5 or so mile > run on my commute that I can dead-stick. I'll have to play with the trip > computer in the Audi. :) > >> As far as safety aspect, I had >> an audi that did this from the factory. 5000TD, if your foot was >> completely off the gas it free-wheeled. > > Automatic or manual? Lots of automatic transmissions have an overrun > clutch such that there's no engine braking in top gear. I know the 727 > Torqueflite in my old Jeep was that way. And yes, it's very strange. > > I still get caught out occasionally by the asymmetry of the turbo motor > in the A6. Not nearly as much compression braking as there is power > under boost. ;) > > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
