As already said if you have a low compression engine then lower octane
should be fine. If high compression then you will get the benefit of
better performance and economy with higher octane. Low ethanol is
better in both cases.
Because the fuel today is so different to when these cars were first
produced the original timing specs are no longer relevant. If you get
pinking then back off the timing until you don't at any combination of
throttle opening, revs and load. With high compression and high octane
try advancing bit by bit until you get pinking, then back off a bit till
you don't.
You are less likely to get pinking on low compression even with low
octane fuel, so if you can run the book figures for timing without
pinking then do so. You might get a bit better by advancing, but you
can advance so far that it stalls the starter but still doesn't pink.Â
That's obviously too far.
PaulH.
On 20/09/2023 16:32, i erbs wrote:
> I just got my B running for the first time and have a newbie question.
> I have looked online and got confusing answers.
> What grade petrol do I use? Must I use premium grade? Can I use regular?
> Thanks.
>
> Ira Erbs
> Milwaukie, OR
> 1959 Austin Healey 100-6
> 1967 MGB Roadster
>
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