Re: [FWDLK] octane ratings

[cpollock@xxxxxxxx]

Hi Van,
I don't know the exact date of when it happened but I do know the two biggest factors on the change in gasoline have been compression ratio and emissions.  The latter is what has driven the change for the past 20 or so years.  The early to mid 60's is my guess for compression ratio, and the mid to late 70's when people began to become enviromentally aware for emissions.

Just what I know.  FYI- gasoline in it's pure form is clear. The oil companies add dye for identification and branding.  i.e. Blue Sunoco.

Have Fun,
Chargin'Charles--->>>


> From: van Hoy <vanhilla@xxxxxxxxxxxx>
> Date: 2001/05/01 Tue AM 07:40:03 EDT
> To: L-FORWARDLOOK@xxxxxxxxxxxxx
> Subject: [FWDLK] octane ratings
>
> Perhaps someone out there can enlighten the masses about
> octane ratings.  I know that the octane in the good old days
> was rated differently than the present method which is
> RON+MON/2.
>
> I did a very little research and learned that the Research
> Octane method was invented in the 1920's and the RON
> [Research Octane Number] per se has been used since 1942 and
> formally approved in 1947.  The MON [Motor Octane Number]
> was developed in the 1930's as the ATSM.
>
> One source [www.repairfaq.org/filpg/AUTO/F_Gasoline6.html]
> stated that in the 1930's cars would run better or worse
> depending upon the RON with almost any MON, but that modern
> cars are effected most by the "severity," which is the
> difference between RON and MON.  [ie a change of 1 RON
> matched by an equal opposite change of MON will apparently
> result in the same knock propensity or lack thereof.
>
> It doesn't take a rocket scientist to deduce that we can't
> easily tell the difference between RON and MON using the
> current adding/dividing method.  Do we need to for our old
> cars?  Maybe we should be buying gasoline like a fine wine,
> checking all the ratings to determine the best for our car's
> pallette.  Does the RON rating itself apply better to a
> 1950's car?  Where between 1930's and 1990's did the change
> in engine gasoline demands occur?
>
> Anyone with more knowledge care to share with the group?  A
> little knowledge is a dangerous thing.
>
> --Roger van Hoy, '55DeSoto, '42DeSoto, '66Plymouth,
> '73Duster, '81 Imperial, Washougal, WA|
>