RMC List - Octane boost question

[ltrhead]

Hello Michael,You didn't mention what octane grade (number) you are trying to achieve.If you mix 50% non-ethanol 87 with 50% 91 ethanol, the final octane (theoretically) should be 89.I'm not sure if that meets your requirements, but at least it's a reduced ethanol fuel with some octane improvement.And obviously, the ratios can be varied.Just putting it out there. Hope it helps.Good luck in your gasoline quest.Larry Blasco
-------- Original message --------From: Michael Brittan via RMC-List <rmc-list at corvair.org> Date: 4/24/26  1:47 PM  (GMT-07:00) To: rmc-list at corvair.org Subject: RMC List - Octane boost question Hello All,I like to use only non-ethanol gas in my cars (Spyder and 2x164/110 Monzas).  87 non-ethanol is available in my area of SE Denver at a reasonable price.  Preferred 91 octane non-ethanol is available at the Mobil station in Lakewood, but at a huge price premium and a 30-mile round-trip (+- 2 gals of gas consumption right there) from my home.I can eliminate the pre-ignition with expensive octane booster containing MMT.  Cheaper brands contain alcohols, so defeat the purpose of using no-ethanol gas and don't raise the octane as much per ounce of dosage.I'd welcome members' views on using such octane boosters and whether they may have preferred brands.  Could any harmful side-effects be experienced with our trusty Corvair engines using these boosters?  What do members feel about using standard pump 91 octane containing ethanol?Best,Michael
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