Re: [ST] Petro Rating

["Enrico Schuerrer" <enrico@xxxxxx>]

- ----- Original Message ----- 
From: "Masiak, Richard" <Richard_Masiak@xxxxxxxxxxxxxxxx>
To: <ST@xxxxxxxxxxxxxx>
Sent: Monday, November 01, 2004 3:35 PM
Subject: [ST] Petro Rating


> You raise an interesting point when you said "Premium Unleaded fuel (95
RON I think)"
>
> My RS manual says a minimum of 92 RON.  The way fuel is rated in the US is
"octane" which is R+M/2  or RON + MON/2.
>
> Pump gas and most race gasoline is rated in the (R+M)/2 fashion, which
refers to an average of two ways that octane is measured: Research and Motor
octane number. Research octane uses an industry-standard, single-cylinder
test engine run at 600 rpm with an inlet-air temperature of 100 degrees
Fahrenheit. Motor octane numbers are generated with this same test engine
operating at 900 rpm with inlet air at 300 degrees F. Typically, Research
octane numbers are 8 to 10 numbers higher than Motor octane numbers, since
higher inlet air temperatures will increase an engine's tendency to
detonate. There is an almost infinite number of ways to create the (R+M)/2
octane rating. According to Wusz, higher Research numbers will reduce
part-throttle detonation, while higher Motor numbers are better for
detonation resistance at wide-open throttle.
>
> So how do we really know what the RON of a fuel?  I called several
manufacturers like Texaco, Mobil, and Shell.  I could not get an answer from
any of them.  My Triumph tech said that 89 octane usually should have a RON
of 92, but it's not guaranteed.  I'm sure the numbers vary from batch to
batch.
>
> The best suggestion I got was to just try various manufacturer's 89 octane
gas and watch for knocking.  As long as the engine doesn't knock you're
fine.
>
> So why do our wonderful engineers at Triumph spec. a Research Octane
Number when the majority of fuels are rated using the average of the
Research & Motor Octane numbers?
>
> Rich

In Europe, especially in AT, DE, IT and FR you will find the ROZ (Research
Octane). All fuel is unleaded - "Normal" has 92 ROZ, "Super" has 95 ROZ,
"sometimes "Super Plus" or "Premium" is 98 - 100 ROZ.

In the manual of my '00 ST for the minimum ROZ  is stated a fuel quality
with 95 ROZ. As I have learned in chemistry years ago the difference between
ROZ and MOZ is around 10 which means "Super" quality should have a MOZ of
around 85. So if you will find a gas station with 90 octane it should be ok.

Enrico
- -- 
'00 ST 'BlueBelle'
Vienna, Austria, Europe




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