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Stale Fuel as an Octane Booster
Ivan - 29/3/19 at 03:58 PM

I will soon have about 30 literes of really stale fuel to get rid of - just wondered if i added it at a ratio of about 5% to my Forester XT tank if it would act as an octane booster as most of the volatiles are long gone. It doesn't even smell like petrol any more.

Also wondered what harm it could do?

gremlin1234 - 29/3/19 at 07:41 PM

modern 'standard' 'unleaded' fuel here in the EU has at least 5% alcohol which can absorb water from the air, and if left standing can separate. leaving water at the bottom of the container. you should try to avoid water in the petrol tank.

Angel Acevedo - 30/3/19 at 08:41 AM

quote:
Originally posted by Ivan
I will soon have about 30 literes of really stale fuel to get rid of - just wondered if i added it at a ratio of about 5% to my Forester XT tank if it would act as an octane booster as most of the volatiles are long gone. It doesn't even smell like petrol any more.

Also wondered what harm it could do?


Actually is the other way around.
Heavier oils are more prone to detonation.
On the other side 5% looks good and I think that if it is fuel injected, the computer will adjust for time and mixture therefore you will save 30 lt in the long run...

Ivan - 30/3/19 at 10:14 AM

quote:
Originally posted by Angel Acevedo


Actually is the other way around.
Heavier oils are more prone to detonation.
On the other side 5% looks good and I think that if it is fuel injected, the computer will adjust for time and mixture therefore you will save 30 lt in the long run...


I think you are right after a bit of googling. As I already add octane booster to my Forester (Reduces fuel consumption by 15% and significantly improves driveability - our 95 octane fuel is just too low for the Forester ) I don't think it will work. Will try it once however
just to see.
If it doesn't work will use it in the Cobra which is a lot less sensitive and at about 20l/100km will chew through it quiet quickly