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Ethanol Free Fuel Issue
I have been usng Ethanol free gas for two years as I have a service station close to my airport that carries it. Today on my refueling trip I noticed that the price per gallon had dropped almost $1 since last month, nothing close to the drop of regular gasoline. Looking at the pump more carefully I also noticed that the octane displayed for non ethanol was now 89 vs 92 last month. Indeed the appellation of this type of gas is now Plus vs Premium before. I discussed these changes with the owner who told me that their supplier is now receiving Ethanol free gas that is 90.1 octane and has he did not have stickers with this grade to put on his pump he applied the 89 one.
Now the question is: will my Rotax 912 ULS run on 90 octane gasoline? After a search I found the following thread on the subject: http://www.vansairforce.com/communit...ad.php?t=87540 I am reintroducing this subject because I suspect that what has happened in my area might also have happened elsewhere. If you are using ethanol free gas watch out next time you refuel your RV-12. |
You might get better response to this question if asked in the Rotax Forum.... http://www.rotax-owner.com/en/rotax-...ical-questions
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I think it depends on the supplier. I live in an area of Western Kentucky, near Kentucky Lake, were many station offer what they call boat gas. It is 89 octane ethanol free fuel, which is actually a blend of regular, and premium. I also have a local supplier who sells ethanol free 91 octane. I can get ethanol free 93 octane premium, but I have to drive 60 miles to get it. I do, and carry a 55 gal drum with me. According to that supplier, all of the fuel in our area comes from the same pipeline, located in Nashville TN. He says that only two grades are available, 87 octane regular, and 93 octane premium. He says that anything else is a blend, and that the ethanol is added after the pipe line distribution, not through it. The suppliers blend fuel strictly to lower their cost so that they can offer more competitive pricing. So far, I have been able to get 93 octane premium, but it is at a slightly higher price. For what this is all worth............Tom
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This is why I gave up on using ethanol free fuel. I just use 93 E10 and fly merrily on. It's more important to have the octane than it is to eliminate the alcohol.
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Amen
Randy has it exactly right.
I cannot understand this crazy obsession with not wanting to use E10. As far as I know 93E10 is available everywhere and Rotax engines are approved for running on E10. |
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Good to hear
The success of E10 fuels is good to hear about because getting the ethanol free, 91 octane, is a bit of a drive for me. In the good flying season I use it regularly and fly more frequent. Winter rolls in and I switch to 100LL because of the stability as the plane sits more.
I may start using the 93 E10 this summer and see how it goes. |
Also, gasoline without alcohol has more BTU content. E10 has 96.7% of the energy of straight gasoline. Doubt if you'd notice... :D
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John |
Take a look at the pictures of the fuel pump that was disassembled recently, and posted on this forum, which shows all of that interior corrosion in just 20 hours of operation, which might be another good reason to keep the ethanol out of your gas, in you can.
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In the nice and wet Pacific Northwest, what fuel do you suppose Mr. Van himself, uses in his Rotax? Yep, 93 E10 (I'm told). I fly at least once a week and my -12 sits in a dry hangar. Having the fuel absorb water is a non-issue for me.
BTW, there are thousands of Rotax engines in Europe using 30 percent ethanol based fuels with few issues. I'm not too worried about it but you should use the fuel you feel most comfortable with. If it takes you out of your comfort zone, then don't let anyone tell you what YOU should do. |
Having used E10 almost exclusively in every car, pickup, motorcycle, scooter, mower, snow blower, edger, leaf blower and weed whacker we've owned in the past three decades or so, and having had exactly zero problems related to corrosion, water absorption and hose deterioration... I guess I'm OK with using it in the Rotax if Rotax and Van's are OK with it.
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It is precisely why that kind of corrosion formed because the water in 100LL and ethanol free mogas separates out and settles in low spots in the fuel system. As someone pointed out in that thread, ethanol mogas keeps the water in suspension and it passes harmlessly through the combustion cycle. |
Initially (the first 6 month I flew my -12) I used E10 premium, without any problem. Then comes winter and the plane was left about 2 months with a full tank of E10 gasoline. My local Rotax guy told me that, depending on weather conditions, E10 gas may start degrading after 1 month of storage. I did not want to take the risk and dumped the content of the tank which was a bit cumbersome... and promised myself not to use Ethanol fuel any longer. As the service station is close to my A/P it worked well until... go back to the first post of this thread.
Still mulling what to do based on the interesting feed back provided above. At this point I am reluctant trusting any Ethanol free source for aviation usage. My preference would be to go back to E10 premium, except for January and February when I would fill the tank with 100LL. I figure it would result in 100LL usage low enough (including refills on trip stops during the rest of the year) to make minimum lead deposit inside the engine. Only time will tell if this is effective and workable. |
There may be another option to consider. I am certainly no expert, but from what I have read what you're concerned about is not only water absorption from the atmosphere but also octane loss from evaporation. The water problem can be minimized by keeping the tank full and the cap on. Less surface area exposed to air, and less air exchange with the humid outside world, means less water absorbed.
Everything I have read indicates that if you keep the tank FULL, you have less to worry about. There's less surface area to either absorb water from the atmosphere, or evaporate the lighter hydrocarbons. On the other hand, if you have a gallon or two of room in the tank, topping it with 100LL would probably provide a pretty good little boost for fuel that's been sitting for a few weeks. |
I just go down the street and buy what ever comes out of the premium pump. In 420 hours and 4 years I haven't fallen out of the sky yet!😀
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What filters are you guys referring to? The gascolator or an inline filter you use during fueling?
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Is the an additive one can put in to get the octane from 90 to 92?
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John |
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A little update: I found a Sunoco service station serving 93 octane ethanol free premium a month ago but... on my last trip it had gone down to 91! The owner says he will know in April if it goes back to 93 (that would be for summer). In the mean time he sells an "octane booster" additive that claims to bring the octane of a 17 Gal. load to 100 octane. I checked the container but there were no indication of the composition of the content. I doubt Rotax would agree to support such mixture under warranty.
Back to ethanol fuel for the time beeing. |
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I've used ethanol free 91 without issue. I have 110hrs over 3 years now.
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From my copy of the POH:
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Lots of good stuff here. Its "must read" material for properly maintaining your Rotax. |
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Thank you all for the clarification on the 91 AKI requirement. I was under the wrong assumption that 91 was the intermediate fuel grade sold in most service stations that I remembered as inadequate for the Rotax. As a matter of fact the intermediate grade is 89 not 91. My mistake!
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I guess the next obvious question is how trustworthy the octane rating on the pump is. I don't have any way to test the actual octane that I know of. If 91 is our minimum and the pump is labelled "91 octane", can we trust it?
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Our local stations (regardless of "brand") that had 93 non-ethanol switched to 90 at the same time a few months ago. |
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John |
A fuel distributor told me that removal of the 10% ethanol from 93 AKI premium motor gasoline reduces the rating to 90 AKI. Many marinas offer that variation as some older boat engines can not tolerate ethanol.
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one comment
I know from past experience that if you fill up the first small amount is what the person ahead of you used..ie; 87 octane..that is what was in hose and pump ...so when I filled up scooter which took very small amount..2 gallons a good portion was what ever the person ahead of me used..don't know if it is relavent...just food for thought...
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