[Mgs] Petrol

[h.duinhoven at planet.nl]

It is not for the octane grade only, that premium fuel is the best choice. 
It is best to avoid ethanol additions as much as possible. 
In the Netherlands we still can choose between 5% or 10% ethanol. 
Premium fuel 5% is the best and offers the least chance of damaging the old type of fuel lines - hoses and gaskets in the carburettors. 
It also offers 98% octane, which had the least chance of pings.
The final advantage of 5% ethanol is, that this fuel has a higher energy content, which gives a better mpg figure. 
So it is worth while to make the best choice. 
I even use 5% ethanol premium fuel in my daily driver Mazda 6, which gives a nice fuel economy and a clean fuel system.

Cheers, Hans
No BGT anymore - just enjoying MG news


-----Oorspronkelijk bericht-----
Van: Mgs <mgs-bounces at autox.team.net> Namens Paul Hunt
Verzonden: donderdag 21 september 2023 09:47
Aan: mgs at autox.team.net
Onderwerp: Re: [Mgs] Petrol

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. 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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