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Discussion Topic:
Octane & Ethanol Free Fuel
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len47merc |
08-23-2016 @ 10:42 AM
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Senior
Posts: 1165
Joined: Oct 2013
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Gents - while not having been overly concerned about running ethanol free fuel in my '47 59AB, I have, as a matter of principle only, run 89 octane ethanol free fuel. Fundamentally this is driven by the reasonably-priced availability locally as well as a post from over a year ago here stating that fuel 'back in the day' was 89 octane. I never personally validated the latter. During the recent trip to Gettysburg I mapped out each stop for 89 octane ethanol free fuel using pure-gas.com. Only had to stop for an unplanned peace-of-mind 3-gallon splash of 10% ethanol one time during the road tour to the car museum. With local advancements and progress my tried and true local source for 89 octane ethanol free fuel has been removed/demolished and a drug store/mobile phone store/fast food/whatever is going back in its place. This leaves me with only a 93 octane ethanol free fuel source within a 15 mile radius of home (the 93 octance source is 3.5 miles away from home). At least the price is the same - $2.49/gal. 87 & 89 octane ethanol free options exist 18 and 22 miles from home. So - the questions are: 1) What are the consequences, positive and/or negative, if any, of running 93 octane in stock/original/non-modified flatheads? 2) Are fuel preservatives such as Sta-Bil strictly for ethanol-containing fuel or do any of you use it also in ethanol-free fuel? If so on the latter is there a technical justification for it or is it used solely for peace-of-mind? 3) Lastly, how long do youse guys plan on your car being idled before feeling the need to throw some fuel preservative into the tank, and do you have any experience/data that supports that time period? Thanks - Steve
This message was edited by len47merc on 8-23-16 @ 10:55 AM
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ford38v8 |
08-23-2016 @ 11:21 AM
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Senior
Posts: 2759
Joined: Oct 2009
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Steve, 89 octane "back in the day" would probably have been the highest octane available. Our cars were built with considerably lower octane in mind. Lead was introduced as an octane booster, now that's gone, but refining methods have enabled higher octane today. A measurement of octane is loosely defined as how fast the flame front travels in an internal combustion engine. High compression engines need it to prevent knock (ping), but our flatties don't need it. A modern means of obtaining high octane is to mix Ethanol with the gasoline. Ethanol being alcohol, contains water, which slows the flame front. Our distributors have a vacuum brake intended to be adjusted to prevent knock while using very low octane fuel. This use no longer being required of the vacuum brake, it should be set with a light drag to prevent the advance plate from erratic bouncing. Now to your questions... 1 - You'll find no difference between octanes available today in the way your flathead performs. 2 - Stabyl is a fuel preservative. It prevents fuel from gumming up the works. Stable Marine, on the other hand, outgasses a vapor that lays on top of the fuel in your tank, which forms a barrier against a rust belt at the upper level of the fuel, caused by the water in ethanol. 3 - For those who drive their old cars daily, Stabyl or Stably Marine is probably not beneficial, but driven only weekly to local car shows, a tank of gas can go sour on you before you know it. I'd use it all the time for local driving, not at all during trips. Just my opinion, of course.
Alan
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len47merc |
08-23-2016 @ 1:56 PM
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Senior
Posts: 1165
Joined: Oct 2013
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Thanks Alan - great feedback. Cutting-n-pasting into my digital library with you as the reference author. I investigated further and am taking your advice on the Marine Sta-Bil particularly given how humid it is here. I run ethanol free fuel in all my Stihl yard equipment and also regular Sta-Bil in those reserve tanks, but have never pursued the 'Marine' product before now. Even though the tank was (and had to be) dumped, cleaned and ultimately coated/sealed after the car's ~35-40 year slumber, at times I drive the car 3-4 times per week, other times it has sat for as much as 10 weeks at a time before taking it out again. So I'll use the Sta-Bil for use here around town but not on road trips to ENMs or to the mountains for the fall foilage in a couple of months. All Good Logic - makes sense to my weak brain. Thanks again -
Steve
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mrtexas |
08-24-2016 @ 5:36 PM
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Member
Posts: 68
Joined: Dec 2011
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Back in the day, early 70s, leaded premium was 100 research octane. Unleaded super today is about 100 research octane more or less. Back in the early 70s leaded regular was 89 octane. Back in the day 1940s leaded regular wasn't 89 octane, more like 75-80. Making higher octane was only possible when refineries started installing platinum reformers and alkylation units in the 1950s and 1960s to make high octane reformate(95-100) out of low octane naphtha(70). After they could make it the refiners started advertising and marketing octane as something that made gasoline "better." It was no better if you had a low compression ratio flathead, just more expensive. You only needed it if you had a high compression high performance engine. Too high an octane has no effect on any car. It is just a waste of money as it costs more to manufacture. Octane is a measure of resistance to ignition. Higher octane is needed with high compression engines like 11:1 vs the 6:1 of a flathead. It is unrelated to energy content. "Ethanol being alcohol, contains water". This is not true. The oil companies go to a lot of trouble to keep water out of ethanol containing fuels. The ethanol is blended out at the gasoline terminals near gas stations rather than at the refinery. You may notice the domed tops on gasoline tanks at terminals. This is to keep the water out. Just a few ppm water in ethanol containing gasoline is enough to make it whitish milky looking and unmarketable. It can also cause the ethanol to drop out of solution. Gasoline doesn't go bad like it used to either. Essentially all gasoline is now hydrotreated to remove the sulfur down to less than 50ppm vs 5000ppm before. This also gets rid of the old time stinky unstable yellow stuff that used to form gums in your gas tank. Now the ethanol can drop out and cause trouble though. Gasoline used to be yellow in color from the unstable stuff, it is now mostly colorless white gas. I spent my career as a chemical engineer in an oil refinery with lots of it looking after gasoline blending operations.
This message was edited by mrtexas on 8-24-16 @ 5:53 PM
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ford38v8 |
08-24-2016 @ 7:46 PM
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Mr. Texas, that's some pretty darn good Oil Company P.R. We've heard about how wonderful MTBE is also. (Coincidentally, MTBE came out of Texas.)
Alan
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Drbrown |
08-24-2016 @ 9:54 PM
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Senior
Posts: 570
Joined: Nov 2013
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I use 87 octane 10 percent ethanol in my stock '47 59AB all the time with no apparent side affects. I do add the blue emzime ethanol additive to my gas and also installed a carburetor and fuel pump that have been rebuilt to avoid ethanol gas damage.
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mrtexas |
08-25-2016 @ 7:38 AM
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Member
Posts: 68
Joined: Dec 2011
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MTBE was wonderful and a cheap octane enhancer. The problem with it was that gas station owners had underground tanks that leaked. My refinery was one of the first to put in an MTBE unit in the late 80s. Government actually encouraged it as it contains oxygen and supposedly burns cleaner. It is hardly oil company PR to tell you not to waste your money on super for an engine that will run on 75 octane.
This message was edited by mrtexas on 8-25-16 @ 6:46 PM
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TomO |
08-25-2016 @ 7:54 AM
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Posts: 7252
Joined: Oct 2009
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The gas that comes from the refinery may not have water in it, but I have had bad gas in my cars several times while on tours. I carry a can of Heet and a can of Seafoam in my trunk to help out when I get the bad gas. The Heet help[s most of the time, but sometimes the gas requires Seafoam and an octane booster to make the car run right. I always try to use the busiest station that has Tier 1 gas.
Tom
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mrtexas |
08-25-2016 @ 2:21 PM
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Member
Posts: 68
Joined: Dec 2011
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You are wasting your money on "octane booster."
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len47merc |
08-25-2016 @ 2:51 PM
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Senior
Posts: 1165
Joined: Oct 2013
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mrtexas - greatly appreciate your technical perspective and sharing of info. Prior to the drive to Gettysburg I was educating myself on octane boosters for the trunk just in case I could not find the 'desired' 89 octane and found quite a bit of writing on the misrepresentations made by octane booster manufacturers. Specifically how much of a booster is actually required to move the octane rating one point, versus how much the manufacturers state on the can that 12-16 oz will raise octane (some claim up to 17 octane points as you know). If you don't mind sharing your knowledge here, please expound a bit more on your comment that "You are wasting your money on "octane booster.". I found this to be the case in my reading and chose not to purchase any - hearing the data and understanding this technically will help all of us. Btw - thanks also to Alan, Tom and Drbrown for your good, sound logic and practical information. Thanks in advance - Steve
This message was edited by len47merc on 8-25-16 @ 2:54 PM
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