fuel mixing question

[Stomps]

Hey.. i got a question for the chemical engineers, fuel refinery workers, mathematicians etc... out there..

Work has given my a BP fuel card... BUT it will only allow me to get basic 91 ron fuel... my daily is a Subaru Liberty GT which requires at least premium (95ron)

I've already checked whether they would let me get one that i can buy anything on and got told to politely fuck myself..

so.. my question is.. can you mix lower and higher ron fuels to achieve a mid point.. sorta..

I dont want to use octane booster because 1, that stuff is shit for your injectors, plugs etc.. and 2. most of them do diddly squat..

so, say hypothetically i have a 60L tank..

what mixture of Ultimate and regular unleaded could i run to achieve roughly 95 ron?

would this even work in the first place?

It's kinda a shit solution because im still paying for fuel if i do that, but at least a full tank will cost me ~$40 instead of ~$80..

suggestions, answers... calls for me to be less of a tightarse..

cheers

Stomps

[banana_socks]

Should be linear, so 40% 91 and 60% 98 will give you about 95.

[Stomps]

that is what i kinda thought... but is it really that simple?

Stomps

[andrew_mx83]

While most of the boosters are shit there was one I used years ago before I discovered lpg which was really good. Its made by some dude (chemical engineer) and sold to the 4x4 crowd (he has heaps of products for them)
It claimed something like a 30Ron increase if you did 1 bottle to one tank, I ran 1/3 - 1/2 bottle per take and got rid of my detonation problem.. I think the brand was ultimate or something like that.


Or just tip a couple litres of diesel in every tank of 91

[banana_socks]

The rating itself means that it has a knock resistance identical to a mixture of heptane (really bad) and octane (really good).
So 91 rated fuel is equivalent to a mixture of 91% octane and 9% heptane. Accordingly 98 fuel would be equivalent to 98% octane and 2% heptane.
If you had a litre of each, you'd get a mixture thats 94.5% octane, so it'd be equivalent to 94.5 rated fuel.

The relationship behind the number might not be linear, but mixing them should be.

[petergoudie]

Even if you don't get the mix perfect remember that the knock sensor will sense for engine knock and retard the ignition to compensate.

[Daddio]

pffft...5L tolulene and fill the rest with 91...

[AAAAGZE]

buy someone else's fuel with the card, get them to buy your 95.

[Stomps]

buy someone else's fuel with the card, get them to buy your 95.

Now that is the best idea yet... just gotta find randoms at the servo

Stomps