Re: 5ktq Fuel Economy

["Wm. Josiah Erikson" <werikson@hampshire.edu>]

Huh. Obviously, I should have said YMMV, and of course what is theoretically true
doesn't always turn out to be true in the real world.
    -Josiah

Todd Phenneger wrote:

> Thats odd,
>         In my 4kq (same motor as JT) I get better Gas milage from Higher
> Octane.  Although, Medium and High appear to be the same, Low Octane gets
> worse Fuel Economy by a bit.
>         So on Long trips on the Highway I use Super but around town it
> doesn't seem to care what I use.
>         L8R
>
>         Todd Phenneger
>         1984 4000s quattro / modified/ awaiting Turbo Transplant.
>         1985 4000 quattro / Silver / Fixing it Up.
>         1987 4000cs quattro / Saphire Metallic Blue/ Girlfriend's
>         1996 A6q / Volcano / Dads Car
>    *****1985 5kt / PARTING OUT!
>
> On Tue, 23 Feb 1999, Wm. Josiah Erikson wrote:
>
> > Nope : )
> > Higher octane gas has LESS power per gallon. It just burns slower, so you
> > don't get the preignition knock (well, I guess I should say that it is less
> > suceptible to spontaneous ignition under pressure). If your knock sensor is
> > constantly backing off the ignition timing because you're running too low
> > octane, I guess I could see that you might get better gas mileage by running
> > higher octane. In my Rabbit, for example, which has a 10.5:1 motor in it, I
> > get better gas mileage and more power out of 91 than 87 (in fact, it really
> > doesn't like to run on 87- complains a lot. I have no knock sensor on it).
> > But in my QSW, I get better gas mileage from 87 (8.5:1 JT motor)
> >     HTH!
> >     -Josiah
> >
> > Todd Phenneger wrote:
> >
> > > >You want to trade?
> > > >I get 13-14MPG in the city and 24-26MPG on the Highway (of course I have
> > > >a
> > > >K24 and 2Bar boost).
> > > >If you want to improve your MPG, use 87 octane, should give you 1-1.5MPG
> > > >more (maybe).
> > > >Avi
> > >
> > >         Uhh, How do you figure.  Higher Octane allows the motor to run
> > > better so you should see better Fuel Economy with the 93 octane.  I do on
> > > my car by a 1-2 mpg.  With Higher Octane you get more power per gallon so
> > > you use less gas.
> > >         Right???
> > >
> > >         Todd Phenneger
> > >         1984 4000s quattro / modified/ awaiting Turbo Transplant.
> > >         1985 4000 quattro / Silver / Fixing it Up.
> > >         1987 4000cs quattro / Saphire Metallic Blue/ Girlfriend's
> > >         1996 A6q / Volcano / Dads Car
> > >    *****1985 5kt / PARTING OUT!
> >