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Old April 23rd 04, 08:58 PM
Friedrich Ostertag
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Hi Gord,

Well, just a comment about domestic automobiles, I didn't mean to
indicate that I operate them below the manufacturers specified
octane ratings, after all, I believe that the manufacturer knows
his engine best and I'd never try to second guess him, but I have
all kinds of friends and relatives who use hi octane fuel in
their cars even though low octane is recommended. (complete waste
I feel)


Ah, you're absolutely right there! Sorry for the misunderstanding.
There is no point in using higher octane than what the engine was
designed for. Even knock control will not advance ignition beyond the
calibrated map for the designated fuel.

However a lot of people over here fell for a marketing trick of Shell
Oil: Instead of the 98 octane highest grade fuel sold in Germany and
most euroean countries they offered a 100 octane (by the way, this is
ROZ, not ROZ+MOZ/2 as in the US) fuel called "V-power" with supposedly
all kinds of mysterious additives at 10 ct / Liter premium over other
oil company's 98 octane. Lots of car magazines and also the ADAC (your
AA) tested it in various models and found no difference whatsoever in
power and consumption. Yet Shell sells 10% of it's turnout in V-Power
while the other's only sell 5% 98. Talk about snake oil...

Another thing that I NEVER do is 'recommend to anyone'
what fuel to use. You're bound to get blamed sometime in your
life because a friend's wife got preggy if you do...


:-)

About the direct injection, the Argus (ASW aircraft) used by the
Canadian Armed Forces had Wright R-3350-EA1 engines (3700 BHP)
which had direct fuel injection into the cylinder (not just prior
to the intake valve). The Wright R-3350-89A fitted to the
Fairchild C-119 Packet had 'spinner injection', where the fuel
was injected into the spinner of the supercharger, and the P2V-7
Neptune was set up this way too.


I always find it intriguing, that almost everything we develop today as
supposedly latest techology has been there half a century ago. The only
really new thing in engines today is electronic control.

regards,
Friedrich

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