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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