Max,
That's what I thought (regarding the higher octane in a newer car with a
knock sensor); however, that doesn't apply when the octane is boosted with
Ethanol - I actually get lower gas mileage on my 92 Ford CV when using the
Ethanol.
John Reynolds
1979 MGB (in restoration) - will run on 87, too!
-----Original Message-----
From: Max Heim [mailto:mvheim@studiolimage.com]
Sent: Wednesday, July 05, 2000 4:01 PM
Cc: MG List
Subject: Re: Octane and altitude ratios???
Your Explorer may get better mileage with premium fuel since
it has a
knock sensor, which automatically advances the timing
(within a limited
range) until it encounters knock, then retards until the
knock stops,
several times a second, thus maximizing efficiency based on
current fuel
and conditions. Your B is unable to do this (obviously) so
octane should
not affect gas mileage (unless you adjust the timing to
suit). The oil
companies spend a lot of money trying to insinuate that your
car will go
faster, get better mileage, and be more reliable using their
premium
grade fuels, but for the most part that is baloney. You can
advance the
timing on your B to take advantage of high octane fuel to
get some
benefit, but the "proprietary" additives advertised, such as
"Techroline"
or "Techron", are mainly detergents intended for cleaning
fuel injector
systems on late model vehicles, and do nothing for
carbureted engines.
I have always suspected that the PO of my B's engine had
planed the head
(the donor car had headers and dual Weber DCOEs, which the
wrecker sold
separately), as it seems to require 92 octane fuel at the
stock timing
setting, to avoid knock and overrun. So YMMV. But in general
there is no
benefit to running higher octane than required to avoid
knock.
Andrew B. Lundgren had this to say:
>That damage to the pocket book is what I am trying to
avoid. I have a
>Ford Explorer as well as an MGB that gets 15-16mpg... The
owners manual
>says 87 or higher, but I think that is calcualted for
sea-level. When I
>buy the highest available octain I get better gas
mileage... This is just
>one of lives mysteries I wanted to understand better.
>
>
>On Wed, 5 Jul 2000 Gonaj@aol.com wrote:
>
>> Maybe I have misunderstood something in the past, but I
am under the
>> impression that your engine never needs a lower octant it
simply nosen't
need
>
>> the higher octane. In other words there is no loss or
damage due to higher
>> octane than necessary, other than to your wallet unlike
the damage wich
>> results from lower than necessary octane.
>>
>> If I am wrong here please explain.
>>
>> George
>>
>
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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