starfireelvis Posted July 16, 2022 Share Posted July 16, 2022 I have no doubt that ethanol-free gas is better than any with the corn byproduct in it. My questions involve octane ratings and additives in the “pure” gas. Most ethanol-free gas that I’ve found has an octane rating of 90. I have vehicles with “Ultra-High” Compression—namely, 10.5:1 and 10.25:1. I have always had to use 93 octane, and have also used additives such as 104 octane boost (as well as Sta-Bil 360 to fend off the effects of ethanol). Anything under 93 and the engine knocks and pings. Obviously, there would be no need for the Sta-Bil (except for winter storage, where I use the traditional red stuff) with ethanol-free gas; is it necessary or recommended to continue to use the octane boost with the 90 octane ethanol-free gas? I also know there are places that have 110 octane fuel at places fewer and farther between, and no doubt is more expensive; that is not a practical option for me. Would also like to hear personal experiences using the 90 octane “pure” gas. A couple of people I know and trust recommend it without reservation for my vehicles described above. Thanks in advance for your responses. Link to comment Share on other sites More sharing options...
Jubilee Posted July 16, 2022 Share Posted July 16, 2022 Ethanol free is 87 octane here in the part of Colorado where I live. No problems on 327 sbc 10.5:1+, Qjet, point ignition. Back before ethanol free was available here locally, (had to drive to Wyoming with 55 gal. drum) I use to distill my own ethanol free from 85 octane e-10. I would add 1 bottle of booster to about 20 gallons of finished product. I figured I got the octane up to the high eighties. 327 ran fine on it. I don’t run a lot of timing in my engine. Have you tried backing yours off a little? I’m driving at 5-7 thousand feet, so obviously I can get away with 2-4 less points of octane versus sea level. Link to comment Share on other sites More sharing options...
rocketraider Posted July 16, 2022 Share Posted July 16, 2022 Mike, all I can tell you is try it and see if the engines will tolerate it. Run a couple tankfuls thru them to dilute the ethanol content to near zero percent. That should give you a baseline. Are you running these engines at the recommended 5°BTDC timing setting or have you already retarded it to 2.5°? There's 87 and 90 octane NE available three miles up the road, and a station ten miles away has 93 octane non-ethanol. The Oldsmobiles haven't gone out in years so my only experience is using the 90 in my yard equipment, which seems to like it. Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 16, 2022 Share Posted July 16, 2022 I think having the octane is far more important than getting rid of the ethanol. Too little octane can do some real damage while ethanol doesn't really do much damage unless your car sits for long periods and even then it's usually just hoses and diaphragms. If you drive your car(s) regularly, the effects of ethanol are greatly diminished. 6 1 Link to comment Share on other sites More sharing options...
rocketraider Posted July 16, 2022 Share Posted July 16, 2022 Everyone had high compression engines then but "Ultra High Compression" was one of Oldsmobile's marketing catchphrases in the 60s- accompanied by "Use Premium Fuel Only". These were emblazoned on top of the high-compression engines' aircleaners, along with another "Use Premium Fuel Only" warning on the gas tank cap. I can vouch for using 100+ octane gasoline in my 10.5:1 Starfires and Toronado. They are different cars on that fuel. They'll tolerate 93 unleaded but they don't like it. They love 100LL avgas, but it's tricky to get that now that the local flight station has changed hands. 1 1 Link to comment Share on other sites More sharing options...
Pfeil Posted July 16, 2022 Share Posted July 16, 2022 5 gallons of 100LL to 15 gallons 92 unleaded worked very good in my 455 Pontiac with 10.75 compression. Things got complicated after 911 and required a card to get onto the airport, still my friend had a hangar and a RV6 so I would coordinate a rendezvous for fuel. Then one day we got a visit from the FAA while doing a transfer of fuel to 5-gallon cans. I already knew that it's illegal to run racing fuel with lead and 100LL, but he reiterated the point again. So, a change of heads to lower the compression to 9.8 and the car runs well. 1 Link to comment Share on other sites More sharing options...
Buffalowed Bill Posted July 16, 2022 Share Posted July 16, 2022 I don't have to tell you guys about the use of alcohol in race engines, but I found this article from 1934 that may be of interest. ALCOHOL FUEL FOR HIGH COMPRESSION ENGINES March 1934 - Motor Sport Magazine 1 Link to comment Share on other sites More sharing options...
jp1gt Posted July 17, 2022 Share Posted July 17, 2022 aviation fuel has no alcohol and high octane. Put some wings on your car and drive up to the pump. Link to comment Share on other sites More sharing options...
rocketraider Posted July 17, 2022 Share Posted July 17, 2022 Not to be confused with the turbocharged Jetfire engine. Hmm. There are valid reasons low octane and ethanol fuels are not approved or suitable for aircraft. Why then for motor vehicles?🤔 Link to comment Share on other sites More sharing options...
Pfeil Posted July 17, 2022 Share Posted July 17, 2022 3 hours ago, rocketraider said: Not to be confused with the turbocharged Jetfire engine. Hmm. There are valid reasons low octane and ethanol fuels are not approved or suitable for aircraft. Why then for motor vehicles?🤔 Because automobiles can't fall out of the sky and injure and damage things. Fuel wise, aircraft get the best. FAA doesn't like it when an aeroplane engine loses power due to a fuel related issue. The EPA could care less if you burn a valve with your non protected iron heads, in fact they are probably hoping you scrap that vehicle! 2 Link to comment Share on other sites More sharing options...
intimeold Posted July 17, 2022 Share Posted July 17, 2022 Having worked on scores of small engines, chainsaws, lawn mowers, tractors, motorcycles, etc, etc; I can attest, that ethanol, is a major problem. These engines aren't run on a daily basis month after month; thus the fuel sets it the carburetor. When we take apart an aluminum carburetor and it is caustic, white inside; most times that carb is junk. On a car which may be used more often, this mess in the fuel bowl may not be present. Who wants to take that chance? Ruin a vintage carburetor; leads to $$$ if you can find a replacement. So, Is ethanol or octane a concern for you? If You try to run low octane, you can maybe hear a spark knock, or ping; or your newer car will have a knock sensor to retard the timing. If you don't have a knock sensor, check your timing. Not a big deal. It is a bigger deal to remove your carburetor and disassemble to look for corrosion. Your choice. Link to comment Share on other sites More sharing options...
trimacar Posted July 17, 2022 Share Posted July 17, 2022 My son just sold a Moped he'd had for a little over a year. His girlfriend drove it about 50 miles, then it was put in storage in my warehouse. Go to start it, won't run at all. Carb was all messed up from the ethanol gas in it, had to buy a new carb and it started right up. Only good news is that the carb only cost $25, and to change it is about a 4 minute job..... 1 Link to comment Share on other sites More sharing options...
Frank DuVal Posted July 18, 2022 Share Posted July 18, 2022 For those of us who live where non-ethanol is not served in any pumps from the Rappahannock to DC, running E-10 is the only option. Not many small airports here either, try to buy avgas at Dulles?🙄 2 Link to comment Share on other sites More sharing options...
Pfeil Posted July 18, 2022 Share Posted July 18, 2022 1 minute ago, Frank DuVal said: For those of us who live where non-ethanol is not served in any pumps from the Rappahannock to DC, running E-10 is the only option. Not many small airports here either, try to buy avgas at Dulles?🙄 Thats right! Exhausting 100LL from a car is illegal, but they don't mind exhausting lead from 100LL on you flying overhead. Link to comment Share on other sites More sharing options...
rocketraider Posted July 18, 2022 Share Posted July 18, 2022 45 minutes ago, Frank DuVal said: For those of us who live where non-ethanol is not served in any pumps from the Rappahannock to DC, running E-10 is the only option. Not many small airports here either, try to buy avgas at Dulles?🙄 Sheetz or Wawa don't have it? All Sheetz here have 90 octane NE. Maybe go west of F-burg and see what's available in farm country? I know of one Spirit station in Winchester with 90NE but that's 90 miles from you. We used to fill up my bud's 403-powered Estate Wagon there coming home from Carlisle, and that tank of fuel would get us back home with a quarter tank to spare. 3 guys, luggage and several hundred pounds of swap meet loot, and that wagon would deliver 19mpg on that gasoline. With a rebuilt distributor and new timing chain and catalytic converter, it may do better than that if we ever go again! For comparison: on 87 E10, 16mpg tops without the weight of the swap meet goodies. Link to comment Share on other sites More sharing options...
Glen Andrews Posted August 7, 2022 Share Posted August 7, 2022 Man do I feel fortunate after reading this thread. I am about 25 miles north of Raleigh, NC, in a sort of rural area where there are a lot of small engines used. There is a country store 4 miles from me that has 87 non ethanol, that I can use in my '38 Chevy pickup which has a compression ratio of 6.25 to 1, and at the same place he has 93 non ethanol which I use in my '99 Corvette. He gets his gas from the terminal about 60 miles away which is near Smithfield/Selma NC, near exit 97 of I-95, that mile marker translates to approximately half way between the S Carolina and Virginia border. His other two offerings for fuels are 87 Ethanol and Diesel; and I can buy ammo there too. 2 Link to comment Share on other sites More sharing options...
rocketraider Posted August 7, 2022 Share Posted August 7, 2022 Some years back, gasoline in Roxboro NC area came from the Selma/Kenly terminal. It was formulated different than what came out of the Greensboro tank farm. I can vouch for better gas mileage and performance on the Kenly gas. Charlotte gas too. Can't tell you the times my 350 Olds wagon delivered 30% better mileage using those than the Greensboro-sourced gas I was saddled with locally. Sadly, all fuel in this area is now sourced from Greensboro tank farm. The Triad is in a different EPA compliance area and everything in 60 miles of Greensboro has to use their junky fuel formula. Link to comment Share on other sites More sharing options...
John348 Posted August 8, 2022 Share Posted August 8, 2022 The ethanol fuel is real rough on your rubber hoses and fuel pumps as well. Link to comment Share on other sites More sharing options...
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