Or at least you'll get better brake pad mileage if nothing else.
----- Original Message ----- From: "Aleksandr Milewski" <[EMAIL PROTECTED]> To: "Ken Bogart" <[EMAIL PROTECTED]> Cc: "Bill Cardell" <[EMAIL PROTECTED]>; "miatapower List" <[email protected]> Sent: Monday, June 16, 2008 11:31 AM Subject: Re: MPG up 50% so far > Right, but this assumes that there is no compression braking in the > engine. You can't do the same coast in gear because you have to turn > the motor/pump air through it. > > Now, if you're braking during that coast to keep your speed down, > you'll get better fuel economy staying in gear and using the engine > for most of that braking. > > -Z > > On Jun 16, 2008, at 10:06 AM, Ken Bogart wrote: > >> 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 > > _______________________________________________ > 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
