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Mogas vs. 100LL?
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 |
The link isn't working, anxious to see what you found at Wal-Mart to transport fuel inside your vehicle.
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MoGas Vs 100LL
Quote:
Besides the need for ethanol compliant hoses (including the oil cooler hoses), What I have found is that there can be no 90* fittings from the engine mechanical pump back to the aux fuel pump. I have also added an independent fuel pressure sensing system that automatically turns on the aux pump if a low fuel pressure event occurs. This auto aux pump circuit can trigger on very hot summer days, or on initial steep climb outs on hot days. I have NEVER had an engine loss of power event. All fuel related components must be ethanol compliant. The Lycoming fuel pump was the ONLY component that I couldn't get technical compliance for. But when searching for replacement fuel pumps (and their history) in countries that use ethanol based fuels (think Brazil) I found that they were not having issues with standard Lycoming fuel pumps. Nor have I after five years of using ethanol based fuel. If I were to build another RV, I'd be putting a fuel pump in both tanks, and have a third aux pump as well. I would then remove the engine driven pump. |
I am guessing he meant this.
https://www.walmart.com/ip/John-Dow-...Tank/536931984 It says for diesel, what is different for holding gas? |
I've been running 91E10 for the last 350-ish hours, with occasional 100LL from a long cross-country. Engine is quite happy with it, but I've done considerable modification on the fuel system to keep the fuel cool and not boiling in the FWF area. I get excellent service now out here in hot west Texas weather, including flights into the lower flight levels. Highest I've been with it so far is FL230, but FL190 is realistically the highest reasonable altitude for normal use, anything more than that is just for bragging rights.
Double-firesleeved every fuel line FWF for insulation and heatshields near exhaust pipes Removed engine driven fuel pump Dual electric pumps (parallel for failure protection) through an Andair duplex valve AFP purge valve installed for hot-start fuel pre-circulation to return hot fuel to the tanks before start Changed to .022" orifices on the injectors (Gami) for better idling. This requires a higher fuel supply pressure for fuel-power flow, I'm running about 42 psig to the servo. I'm buying at Sams club in a 125-gallon stainless tank with a 12vdc pump, just load it in the back of the pickup with a forklift and drop it back at the hangar. $2.47/gal a few weeks ago. |
What you haven?t mentioned is detonation resistance. 93 car gas is about 89 motor octane - quite a bit less than 100. With 8.5:1 pistons I?d think you?re pushing the limits. But without testing, I really don?t know.
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I run 92 octane non-ethanol gas in my Sonerai. Granted, its only a 10gal tank. But, I wouldn't hesitate to cary 4 5 gal jugs of non-E for blending with 100LL in an RV when at home.
Below is what I carry my Non-E in, in the back seat floor pan of my Honda Accord. Fill to to exactly 5 gal, leave space for expansion, and cap them off good and snug. I don't have any gas fumes in the car at all. https://www.amazon.com/VP-Gallon-Squ...40825168&psc=1 Check out https://www.pure-gas.org for availability of non-E gas. |
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. |
My engine is liquid cooled, 10.8-1 comp cylinders. The manufacturer recommends 92 Octane minimum.
This is the 58 gallon transport tank: Emiliana Serbatoi Portable Gasoline Tank, 58-gallons (from Italy). https://www.walmart.com/ip/Emiliana-...BoCJZwQAvD_BwE |
One potential problem with transporting gasoline in some of these larger tanks is that they are most likely not certified for gasoline. Federal hazmat regulations prohibit it. And most states go by the federal code, to my knowledge.
Although it may not necessarily be dangerous, if you get caught filling a tank that is only certified for combustibles (diesel, kerosene, etc.) by a fire marshal or DOT officer, it could be problematic. |
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