<VV> Octane Number

[Marc Marcoulides]

I now have a 03 Ford F150 for my daily driver that is factory equipt for gasoline or natural gas. When I stop at my local gas station that has both products the pump is marked with an octane rating of 120. If I am driving and the natural gas tank empties my truck will swich to gasoline without missing a beat. I have often wondered how I would be able to do with CNG in my Corvair. 


-----Original Message-----
>From: Joel McGregor <joel at joelsplace.com>
>Sent: Apr 25, 2012 10:44 AM
>To: "virtualvairs at corvair.org" <virtualvairs at corvair.org>
>Subject: Re: <VV> Octane Number
>
>The numbers don't tell the truth compared to 20 years ago either.  I used to be able to run 50/50 93 unleaded/89 leaded pump gas in my motorcycle back then with no detonation.  Now I have to run 100LL.  It pings and clatters like crazy with today's "93".  It seems to have gotten worse when they took the lead out and even worse with the ethanol in.  I did richen the jetting to make up for the ethanol.  I can't remember when they started putting ethanol in gasoline but I remember having issues starting around 15 years ago.
>Joel McGregor
>________________________________________
>From: virtualvairs-bounces at corvair.org [virtualvairs-bounces at corvair.org] On Behalf Of Dave Keillor [dkeillor at tconcepts.com]
>Sent: Wednesday, April 25, 2012 12:17 PM
>To: virtualvairs at corvair.org
>Subject: <VV> Octane Number
>
>The octane ratings posted on pumps today can't be directly compared with
>the octane ratings back in the gud-ole-daze (pre-70s).  In those days, the
>octane ratings used the RON method of measurement, today it's (RON +
>MON)/2.  Since RON generally yields the higher octane number, today's
>numbers are a few points lower than those of yesteryear.
>
>(RON = Research Octane Number; MON = Motor Octane Number)
>
>Dave Keillor
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