Re: octane meathods

[Greg & Britt <image_one@earthlink.net>]

> 
> OK, after answering the towing-q's question, I glanced at the nearby pages
> listing engine types, and lo and behold, the MC engine minimum octane is
> 91RON, recommended 95RON.
> Uh...87 seems to work fine...is the big-number-octane-rating not RON?  I
> know of  the existance of more than one octane rating; what's the typical
> big-number-on-the-yellow-sticker-at-the-gas-pump number calculated by?

RON is Research Octane Number. Typically used in Europe. In the U.S. the
octane numbers you see are a combination of Resarch and Motor Method
i.e. R+M/2.
Motor Method typically gives a lower value for a given anti-knock
resistance.
The testing proceedures differ, thats why the discrepancy in octane
numbers.

> The only thing I know of with an "octane" above 91 is 100LL(Low Lead :),
> and Hansom Base is just a tad too far for my refuling needs :)

Blue 100LL (2gm pb/gal) is a totally different animal. It replaced the
green 100-130 (4gm pb/gal) octane fuel(100MM-130RON). 

 I’ve never got the staight story on 100LL(or red 87), is it R+M/2 or
just the MM octane number? Don’t know.
 You can find 98-100 octane (R+M/2) in various parts of the country.
Usually sold as unleaded racing fuel, 2bucks/gal and up....

If your not noting a performance difference in fuel octane your MC
engine may only be running the 87 octane map in the ECU. Lots of
messages on the list lately on this subject.

GT
84 5KT (KH)
87 5KCST (MC)