On 26 Dec 2006 at 13:48, John Macartney wrote:
> It's clear to me in the UK that the US and Europe generally
> have different methods for calculating octane. We use RM for
> 'research method, whereas I think you guys in the US have a
> comparable fuel, though the octane is measured differently?
Pumps used to list it as (R+M)/2. I haven't noticed lately, but it
has been this way for at least 25 years, IIRC. AS I understand it,
it lowered the rating by a click or two, but I can't recall which was
the lower of the two ratings, R or M. But the specified target of 95
was for an '80 car, well after that had become the standard for
octane rating here in the US. So unless that target was meant for UK
gas and never corrected for the US, the 95 figure would still apply.
> I was taken for a ride in one of the last US spec Spitfires less
> than a month ago that had been re-imported to the UK...
> there was just no way it would do more than 60mph.
Wow. They do not have that reputation here, AFAIK. Even before my
tired engine was rebuilt it had no trouble doing 85. I'm pretty sure
it would do 90 now, though I have never tried. Admittedly it does
not have all the original plumbing but it does have some, and back
when Massachusetts' emission rules still applied to '80 cars it met
them with ease.
--
Jim Muller
jimmuller@rcn.com
'80 Spitfire, '70 GT6+
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