I am not understanding..............
If  MON is always lower than the RON rating of the same fuel, how do you
conclude that 93 (r+m)/2 has a lower octane than 91 Ron?
ie 91RON + X MON(a lower numerical value than RON) /2  can't be equal to or
more than 93(r+m)/2 octane.
Hope I am not making a pratt of myself!

Regards
John.

----- Original Message -----
From: Mark Dorm <mark_hb@HOTMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, September 06, 2000 3:12 AM
Subject: Re: petrol consumption

> http://www.bostonengine.com/articles/todaysfuels.html :
>
> "Finally, there is the formula for determining octane which is displayed
on
> the pump. It has changed to the (R+M)/2 method from the old MON (Motor
> Octane Number) method. While in Europe the RON method is the standard.
The
> "R"  in the (R+M)/2 equation stands for Research Octane Number (RON).  The
> "M" in the equation stands for MON.  RON  serves as the essential index of
> acceleration knock. The Motor Octane Number (MON)  provides an indication
of
> the tendency to knock at speed under loads. The MON figures are lower than
> the RON numbers. For instance,  93(R+M)/2 method octane  "high-test " is
not
> even sufficient for the  upright VW engine with a posted minimum RON
octane
> number of 91."
>
> That sticker for the vanagon is 91 RON - but isn't our compression lower
> than 10:1 so isn't it easier for us to use lower octane fuels?
>
>
> >From: Mark Ingalls <ingalls_mark@HOTMAIL.COM>
> >
> >There are different types of octane ratings, the most common in the US is
> >something like RON/MON. The Volks I believe used to just state a RON
number
> >which  "IF"  I remember correctly is higher than the equivelant RON/MON.
It
> >should be specified on the Gas Pump.
> >
> >Go here for to the "fuel section" for all you want to know about Octane:
> >
> >
> >http://www.geocities.com/motorcity/lane/1970
> >
> >
> >
> >Mark Ingalls
> >
> >
> >>From: Dan Landry <landry_skidd@HOTMAIL.COM>
> >>Reply-To: Dan Landry <landry_skidd@HOTMAIL.COM>
> >>To: vanagon@GERRY.VANAGON.COM
> >>Subject: Re: petrol consumption
> >>Date: Tue, 5 Sep 2000 09:25:48 ADT
> >>
> >>There's a sticker beside my fuel cap than says minimum octane to put
into
> >>the tank is 91.
> >>
> >>Danl
> >>
> >>Bedford, Nova Scotia
> >>
> >>
> >>----Original Message Follows----
> >>From: Bill Hayeslip <whayeslip@JUNO.COM>
> >>Reply-To: whayeslip@JUNO.COM
> >>To: vanagon@GERRY.VANAGON.COM
> >>Subject: petrol consumption
> >>Date: Mon, 4 Sep 2000 22:21:02 -0400
> >>
> >>In reading the discussions of the various mpg averages, I noticed that
> >>many of the vans are using a higher octane. Should the 2.1 engine be
> >>running on the higher octane or is it ok to run on the regular 87? And
> >>btw I'm getting 17.76 mpg local and 20.75 mpg highway.
> >>
> >>Bill H.
> >>88 GL
> >>Pgh.,Pa.
> >>
>
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