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08-07-2019, 12:49 PM
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Join Date: May 2012
Location: Jazz Town, USA, TX
Posts: 501
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Quote:
Originally Posted by Greenley
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The gasoline version has some sort of built in spark suppression.
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Annual dues paid - 6-13-2020
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08-07-2019, 01:31 PM
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Join Date: Dec 2018
Location: NC
Posts: 136
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Quote:
Originally Posted by TXFlyGuy
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I was just going to ask how long the E0 car gas stays ?fresh?? I use seafoam to stabilize the fuel in my beach cruiser truck which can go months between fill ups and never has any fuel issues but is it safe to use a stabilizer in a proper aircraft engine?
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08-07-2019, 02:26 PM
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Join Date: Jan 2016
Location: Portland Oregon Area
Posts: 81
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Quote:
Originally Posted by Kooshball
I was just going to ask how long the E0 car gas stays ?fresh?? I use seafoam to stabilize the fuel in my beach cruiser truck which can go months between fill ups and never has any fuel issues but is it safe to use a stabilizer in a proper aircraft engine?
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I ran 91E10 in a Rotax 912. 2 to 3 months between flights and never a problem. I used sea foam as well.
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_________________
Jim
Rans S20 Raven Sold Built in 2016
ATP, CFI/II/MEI
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08-07-2019, 07:44 PM
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Join Date: Aug 2010
Location: Newport News, Va
Posts: 325
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Quote:
Originally Posted by airguy
With respect to detonation - I'm running 8.7:1 compression with piston oil squirters on my IO360, Superior forward facing induction and Bendix servo. During the hot summertime I can make the engine go into detonation by running LOP down low (below about 6000) and running just lean of peak during a hard climb - just about the worst case scenario - so I normally climb full ROP until that point then go WOTLOP and transition to cruise-climb at about 800 feet per minute and adjust mixture to keep my hottest cylinder (#4 for me) at or below 400F until level-off.
The key take-away here - detonation is a real thing and can happen with inferior fuels if you don't pay attention. Instrumentation is required, and thorough testing is desired.
EDIT - I've run some tanks of 93E10 as well - and have not experienced any detonation with that mix, though I didn't really try to find it either. Apparently the detonation margin curve runs out of headroom in the 91-93 octane region, and we are running very close to the edge.
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Hi Greg... question.... how do you detect detonation? Thanks
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08-08-2019, 07:20 AM
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Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,145
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Quote:
Originally Posted by johnbright
Hi Greg... question.... how do you detect detonation? Thanks
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You can't hear it, you can't even really use a decent detonation detector on the engine due to all the mechanical noise on an air cooled engine. The way I look for it and detect it is watching my CHT's very closely when I'm operating close to the bears den. When you have a cylinder in the 400F region and it suddenly takes off climbing 1-2 degrees per second, it's almost certainly a detonation event. Time to do something NOW to stop it. Full rich, lower the manifold pressure, lower the nose to get some cooling air, or all of those. Once you've got a cylinder hot enough to detonate you'll create hot spots inside the combustion chamber that will keep it going, and lead to pre-ignition. That, in the famous words of Ricky Ricardo, is "bad bongos". Get back to a stable cool operating region and let the cylinder cool off, and then try again.
Caution is advised here - engine damage can occur very quickly when you get into detonation/pre-ignition operating ranges. This is not an area to play with unless you are prepared for dealing with the consequences. If you let the cylinder go from detonation to full pre-ignition, you can scrap a piston within a few seconds and be looking at a full engine rebuild.
I certainly would not recommend that others do what I am doing - you may have really good results running 93 octane, but wipe out your engine trying to run 91. I'm comfortable running mine on 91E10 but I won't let anyone else do it with my airplane. If someone else is going to be PIC in my airplane it will be running 100LL.
__________________
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid 
N16GN flying 700 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, 430W
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
Last edited by airguy : 08-08-2019 at 07:29 AM.
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08-08-2019, 08:28 AM
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Join Date: May 2012
Location: Jazz Town, USA, TX
Posts: 501
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That is part of the beauty of a non-standard engine, liquid cooled, with an ECU. Knock sensors / anti-detonation detection, can be set up to let you know what is happening.
But with the V8, being set to run on 92/93 Octane E10 pump gas, it should never really be a factor.
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Annual dues paid - 6-13-2020
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08-08-2019, 08:31 AM
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Join Date: Jul 2014
Location: SE Ohio
Posts: 39
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Quote:
Originally Posted by TXFlyGuy
Okay...certainly this has been beat to death on this forum. But I'm curious how many here actually burn 93 Octane pump gas in their RV's?
After reading more about the auto fuel here in North Texas, we have "reformulated fuel" year round. This has the benefit of cleaner burning, with a much lower RVP (7.8, close to 100LL of max 7.0) number making flying at altitude a non-issue.
We might just purchase one of the 58 gallon tanks, with a self contained fuel pump and carry it in the rear of my Explorer.
The fuel lines in use are alcohol resistant, and chemical resistant. So burning the E10 fuel is not a problem, and the auto engines we are using were designed to run on this.
The benefits of burning 93 Octane pump gas:
1. $2.80/gallon vs. $5.00/gallon for 100LL.
2. No lead, so your engine burns much cleaner.
3. Longer spark plug life.
4. Longer engine oil life.
5. No ugly exhaust smudge down the side of your cowling.
We found a good means of transporting fuel here:
https://www.walmart.com/ip/Emiliana-...BoCJZwQAvD_BwE
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Ive been burning 91 octane ethanol free fuel mixed with 100LL mix for 5 years now in my YIO-360-M1B. The only problem noticed is mag drop higher than normal (>125rpm) on hot days
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08-08-2019, 10:10 AM
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Join Date: Dec 2007
Location: Brentwood, CA
Posts: 659
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I run 91UL almost exclusively for daily use. But when I travel, I burn 100LL with Decalin.
Looking at the price of the tank from Walmart at about $871, you can get an actual DOT approved gas tank from www.attatank.com for your truck bed, which is what I did. Including the pump it was about $1300. However, at about 200 hours a year at 5 gallons per hour, the payback is pretty quick. You can haul up to 119 gallons.
Additionally, here is Wackifornia, you can file to refund the road taxes at 58? a gallon annually, so if I burn 1000 gallons, I can get $580 back annually. That alone pays for the tank within a couple years; sooner if you're burning more, which I assume most folks are in the 8-12 gph range.
Also, regarding the difference between a diesel only and gas tank, keep in mind that you need a static line for diesel; the big difference is that the tanks for "diesel only" are generally not certified for gasoline. Additionally, if you're running gas with ethanol, the pump seals should be viton, which they may not be in a diesel only pump. Other than that, it's just a tank.
__________________
Ron Gawer
- RV10, Build in progress.
- RV12, N975G, "The Commuter"...many great hours and happy landings so far.
- Several others that are now just great memories for me.
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08-08-2019, 11:17 AM
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Join Date: Aug 2010
Location: Newport News, Va
Posts: 325
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Detonation detection, thanks for the explanation.
Quote:
Originally Posted by airguy
You can't hear it, you can't even really use a decent detonation detector on the engine due to all the mechanical noise on an air cooled engine. The way I look for it and detect it is watching my CHT's very closely when I'm operating close to the bears den. When you have a cylinder in the 400F region and it suddenly takes off climbing 1-2 degrees per second, it's almost certainly a detonation event. Time to do something NOW to stop it. Full rich, lower the manifold pressure, lower the nose to get some cooling air, or all of those. Once you've got a cylinder hot enough to detonate you'll create hot spots inside the combustion chamber that will keep it going, and lead to pre-ignition. That, in the famous words of Ricky Ricardo, is "bad bongos". Get back to a stable cool operating region and let the cylinder cool off, and then try again.
Caution is advised here - engine damage can occur very quickly when you get into detonation/pre-ignition operating ranges. This is not an area to play with unless you are prepared for dealing with the consequences. If you let the cylinder go from detonation to full pre-ignition, you can scrap a piston within a few seconds and be looking at a full engine rebuild.
I certainly would not recommend that others do what I am doing - you may have really good results running 93 octane, but wipe out your engine trying to run 91. I'm comfortable running mine on 91E10 but I won't let anyone else do it with my airplane. If someone else is going to be PIC in my airplane it will be running 100LL.
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Thanks Greg for the explanation of detonation detection!
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