AV gas $5.60,,, 92 pure auto gas $4.15

[Russ McCutcheon]

I have asked and searched and only Rocket Bob would say he thought ethanol free 92 will work fine in my 8.7 to 1 compression ratio IO-360-A1A, straight mags, 20 degrees timing advance. Well AV gas just hit $5.60 a gallon while I can get pure 92 car gas for $4.15, that?s a huge savings. Now I am testing the waters, adding the 92 to the right tank and keeping the 100LL in the left tank, only 5 gallons added so far, ran great at reduced power cruse climb and cruse, I didn?t expect any trouble with this mix but I will be testing up to full power on straight 92 as I go, I?ll keep you all posted.

[Geico266]

Been running straight 91 octane car gas in my 8.5-1 IO-540 for 5 years now, over 600 hours.

[Kyle Boatright]

Originally Posted by Russ McCutcheon

I have asked and searched and only Rocket Bob would say he thought ethanol free 92 will work fine in my 8.7 to 1 compression ratio IO-360-A1A, straight mags, 20 degrees timing advance. Well AV gas just hit $5.60 a gallon while I can get pure 92 car gas for $4.15, that?s a huge savings. Now I am testing the waters, adding the 92 to the right tank and keeping the 100LL in the left tank, only 5 gallons added so far, ran great at reduced power cruse climb and cruse, I didn?t expect any trouble with this mix but I will be testing up to full power on straight 92 as I go, I?ll keep you all posted.

Russ, how many 95F days do you get up there? Vapor lock is my concern with non-ethanol mogas. My airplane will occasionally have vapor lock problems in the summer when I land, shut down, and restart after a few minutes. I figure it would be much worse with mogas.

On the other hand, two of my airport neighbors run mogas almost exclusively and never complain about vapor lock.

[pkill]

Hello Russ,

Section 2 and Table B2 of Lycoming Service Instruction 1070 Q talks about auto fuel in the IO360-A…


http://www.lycoming.com/support/publ...fs/SI1070Q.pdf


Hope this helps,
pk

[Russ McCutcheon]

Originally Posted by pkill

Hello Russ,

Section 2 and Table B2 of Lycoming Service Instruction 1070 Q talks about auto fuel in the IO360-A?


http://www.lycoming.com/support/publ...fs/SI1070Q.pdf


Hope this helps,
pk

Best I can see is the IO-360-A is only listed for 100/130 or 100LL, I don't see the IO-360-A listed in table B2 only the O-360-A which is not the same engine and has an 8.5 CR. This is why I have asked if anyone is running MOGAS in this engine and no one has said they where or I missed it, I don't know if Rocket Bob said he was or just said it would work. The lack of proof that it will work is why I haven't done it already but now with the price of AV gas what it is, it's time to find out for myself what can be done.

[Russ McCutcheon]

Originally Posted by Kyle Boatright

Russ, how many 95F days do you get up there? Vapor lock is my concern with non-ethanol mogas. My airplane will occasionally have vapor lock problems in the summer when I land, shut down, and restart after a few minutes. I figure it would be much worse with mogas.

On the other hand, two of my airport neighbors run mogas almost exclusively and never complain about vapor lock.

It's not to hot in the NW but I have a stock fuel system so for now and probably in the future I will have 100LL in the left tank, but today I made only two take offs and ran on 100LL for about 2 minuets total out of an hours flying. At some point if the 92 proves to be able to handle full power running I may have to install electric fuel pumps at the wing roots and remove the mechanical pump, this would eliminate vapor lock issues.

[Kyle Boatright]

Originally Posted by Russ McCutcheon

It's not to hot in the NW but I have a stock fuel system so for now and probably in the future I will have 100LL in the left tank, but today I made only two take offs and ran on 100LL for about 2 minuets total out of an hours flying. At some point if the 92 proves to be able to handle full power running I may have to install electric fuel pumps at the wing roots and remove the mechanical pump, this would eliminate vapor lock issues.

I think my issues may be related to the under-cowl gascolator, which is a huge heat sink.

BTW, if octane is your big fear, a little 100LL mixed with your mogas will boost the mix's octane a disproportionate amount. I've been googling around for data, but no joy, as of yet...

[airguy]

Originally Posted by Kyle Boatright

I think my issues may be related to the under-cowl gascolator, which is a huge heat sink.

.... and there is (one of) the main culprit(s), with the other being the fuel pump itself, bolted to the biggest heater in the airplane.

Get rid of the items that heat your fuel, and you'll get rid of the vapor lock problems. There is a good reason the automotive world quit putting engine-driven fuel pumps on vehicles 3 decades ago.

[Russ McCutcheon]

Originally Posted by Kyle Boatright

BTW, if octane is your big fear, a little 100LL mixed with your mogas will boost the mix's octane a disproportionate amount. I've been googling around for data, but no joy, as of yet...

I have heard this too and as confidence grows my left tank may be a 50% mix.

[Sam Buchanan]

Last week I did something I've never done to my RV-6 (O-320, 160 hp, carb) in thirteen years of flying--put car gas in the tanks. We are on the cusp of $7 avgas ($6.50 locally) and that will really hurt my feelings.

I am running a blend of 93 octane non-contaminated auto gas and 100LL. At this point it is about 30% car gas but I will be increasing the ratio. Presently I can buy 15 gal of car gas for the price of 10 gal of 100LL. The savings will accumulate rapidly. Handling the car gas will be somewhat inconvenient, however.

I fear this is the path we will now be following for those of us who don't have an unlimited fuel budget. Best we gather as much info as possible on running our Lycs on car gas. I suspect it will be a smooth transition but old habits sometimes die hard.