Octane Boost - Fact or Myth?

[ewh]

Years age I was told by a respected engineer that if you mix a mid octane gas with a high octane gas, the result would be a gas with an even higher octane. Is this a true synergistic result or just an urban legend?

 

[MacGyverS2000]

You would get an octance with a weighted average of the two values, not higher then either one.

 

[TheBlacksmith]

Maybe years ago... Back when tetra ethyl lead was legal, supposedly Sunoco 260 used lead and other boosters in a synergistic relationship to reach that high octane level (>102), while Amoco was lead free. Possibly mixing Amoco, with its booster with another gas that used lead would have recreated this synergistic effect. I doubt if it would work today, or someone would be selling the modern equivelant of Sunoco 260.

 

[swall]

BMW motorcycle riders learned of this trick back in the early 1980's when leaded regular gas was still available, but leaded premium had been discontinued. We would mix 25% leaded 89 octane gas with 93 octane unleaded premium in order to get the lead the valve seats needed. The one point or so octane boost beyond the 93 was a side benefit.But once the allowable lead content for regular was dropped to .1 gram/gal. this practice was no longer feasible.

 

[patprimmer]

As others have indicated, it is possible to get synergistic effects, but it has not been mentioned that the opposite is also possible.

Commercially available fuels for highway use do vary in composition from grade to grade, from supplier to supplier, from season to season and from region to region.

To try to predict the outcome of blending, without knowledge of all the components in both fuels, would be a very risky thing to do. Just my opinion, but you will most probably get a weighted average octane, but it could also be better or worse than either component on it's own, or somewhere in between.

Regards
pat pprimmer@acay.com.au
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