Octane rating when mixing Regular gas (93octane) with Racing fuel (110) octane.

[mrhemi]

I did start my response by saying "I am reluctant get into this fray". (again)

 

[RemCharger]

I guess I could understand wanting the race gas smell...

 

[Jeff Peterson]

 

[66 Sat]

Not sure I want to get involved in this fray, but the OP did not specify whether the racing fuel was leaded or not.
Back in the day, when I actually worked for Suncor (Canadian Sunoco), we did all of the different blends with pump unleaded, av gas and race gas. All were verified in the Waukeshaw knock engines in the lab. If the race fuel in question is unleaded, the straight ratio math formula can be used. If it is leaded race fuel, it is not that simple.

So @pnora was correct back on page 1.

 

[33 IMP]

Imo, bottom line.....
The actual "number" means nothing. You need to run whatever it takes to not detonate. If that's best available local pump gas, or something to increase detonation resistance, that what you need to do. An octane booster, (if you can find one that actually works!), some avgas, some race gas, whatever.
Experiment! 20 gal tank? Put in 15 gals of the best pump, add two gallons of 110.(or avgas). If that doesnt get it done, toss in another one or two. When I doesnt detonate any more, you're done!
You don't need a degree, or a calculator. You need good hearing, and the ability to read plugs!

 

[33 IMP]

Beware of "octane boosters" that say they'll raise octane by (whatever number) of points. Say five points for discussion.
What that REALLY means is it raises by five DECIMAL points. From 91..... to 91.5!

 

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