<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body dir="auto">Hello Michael,<div dir="auto"><br></div><div dir="auto">You didn't mention what octane grade (number) you are trying to achieve.</div><div dir="auto"><br></div><div dir="auto">If you mix 50% non-ethanol 87 with 50% 91 ethanol, the final octane (theoretically) should be 89.</div><div dir="auto"><br></div><div dir="auto">I'm not sure if that meets your requirements, but at least it's a reduced ethanol fuel with some octane improvement.</div><div dir="auto">And obviously, the ratios can be varied.</div><div dir="auto"><br></div><div dir="auto">Just putting it out there. Hope it helps.</div><div dir="auto">Good luck in your gasoline quest.</div><div dir="auto"><br></div><div dir="auto">Larry Blasco</div><div><br></div><div align="left" dir="auto" style="font-size:100%;color:#000000"><div>-------- Original message --------</div><div>From: Michael Brittan via RMC-List <rmc-list@corvair.org> </div><div>Date: 4/24/26 1:47 PM (GMT-07:00) </div><div>To: rmc-list@corvair.org </div><div>Subject: RMC List - Octane boost question </div><div><br></div></div><div dir="auto">Hello All,<div dir="auto"><br></div><div dir="auto">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.</div><div dir="auto"><br></div><div dir="auto">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.</div><div dir="auto"><br></div><div dir="auto">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?</div><div dir="auto"><br></div><div dir="auto">Best,</div><div dir="auto">Michael</div></div>
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