MoGas with STC in MX7 180B, pros/cons?

Sam Rutherford · Post by **Sam Rutherford** » Mon Jan 14, 2008 10:27 am

Interested to hear from real-world users!

Sam.

Lowflybye · Post by **Lowflybye** » Mon Jan 14, 2008 1:08 pm

We have had our on for about a year now (150+ hours) and love it. No noticable difference in performance, but huge fuel savings. We have a Shell station within 1/2 mile from the airfield that sells alchohol free MoGas so it is very convenient. We purchased a 90 gallon truck bed tank and an electric pump so we just stop by on the way to the airport and fill up. The fuel savings nearly paid for the tank, pump, and STC all within the first year. $1.25 per gallon savings on average @ 8 gallons per hour = $10 per hour savings.

The cons to the deal are that you have to transport your fuel to the airplane. For us it is no big deal as the gas station is so close. The MoGas also stains the wings pretty bad if you over-fill and spill it anywhere. It is pain to clean up the stains.

There is much debate about MoGas being bad for the engine, and so called "proof" on both sides of the argument. We have not noticed any problems as of yet, but at $10 per hour savings we could afford to put on a factory reman engine every 1,000 hours if we wanted to.

We do run MMO in the tanks pretty frequently and put a little (3 - 5 gallons)100LL in the tips about once a month just to keep the transfer pumps lubricated.

mikemike · Post by **mikemike** » Mon Jan 14, 2008 3:28 pm

Deleted

210TC · Post by **210TC** » Mon Jan 14, 2008 6:02 pm

Your engine will last much longer on Mogas. No sticky valves or lead deposites in the combustion chambers. Now, if you could only run Castrol 20/50, but it's not legal.
The only problem ( I'm told) is alcohol. Ran many engines on unleaded without corn, the corn problem has more to do with the other components in the fuel system.
I am doing some testing now and I have found that the knock index drops with corn. Let that be a warning against using it in an airplane engine.
You can buy a tester to check for this unwanted additive.
Lead deposites cause hot spots, hot spots cause DETONATION.
made another boo boo..that was PRE-Ignition.. sorry

Mr. Ed · Post by **Mr. Ed** » Mon Jan 14, 2008 8:14 pm

Anybody know what the cost of making all the mods required for the Maule Mogas STC? Most are just the paperwork and a few stickers but the one for the Maule seems to require much more.

mikemike · Post by **mikemike** » Tue Jan 15, 2008 5:41 am

Ed, I think I paid about $1300.00 four years ago.

Mauler · Post by **Mauler** » Thu Feb 14, 2008 6:33 am

210TC wrote:Your engine will last much longer on Mogas. No sticky valves or lead deposites in the combustion chambers. Now, if you could only run Castrol 20/50, but it's not legal.
The only problem ( I'm told) is alcohol. Ran many engines on unleaded without corn, the corn problem has more to do with the other components in the fuel system.
I am doing some testing now and I have found that the knock index drops with corn. Let that be a warning against using it in an airplane engine.
You can buy a tester to check for this unwanted additive.
Lead deposites cause hot spots, hot spots cause DETONATION.
made another boo boo..that was PRE-Ignition.. sorry

So are YOU running mogas in your 210TC?

Norm · Post by **Norm** » Thu Feb 14, 2008 7:17 am

Is that the 91 octane auto fuel that is used for the 180 hp (non fuel injected) O-360 STC?

I think the compression ratio is 8.5:1 on that engine ... is that correct?

Lowflybye · Post by **Lowflybye** » Thu Feb 14, 2008 9:40 am

Norm wrote:Is that the 91 octane auto fuel that is used for the 180 hp (non fuel injected) O-360 STC?

Yes...91 octane or 100LL is all the STC allows for. Still a good savings even when running premium.

210TC · Post by **210TC** » Thu Feb 14, 2008 3:49 pm

NO, I have never put auto fuel in the 210TC and I won't. If we are ever around a camp fire I will tell why.
Mauler, how are you comming along?