So since this is my first winter owning a airplane I am starting to wonder about our winter fuel. I have seen in the last couple of weeks my fuel mileage in my truck is going down so we must have switched to winter blend fuel at the pumps. Is there a winter blend av gas? does the winter blend auto fuel have any adverse affects running in our planes? I have auto fuel STC for my o-300, just want to know if im going to have any problems this winter with it.

I have run car gas for years, in an O-200, O-300, O-320, and now an O-470. Never a problem in the C150, C170, or C180 using ethanol-free 87 octane regular year-round.
The only trouble I had was in my C150/150. I had what appeared to be a vapor-lock issue, on a couple of extremely warm days while running what I assume was winter-blend mogas. After that I ran 50/50 100LL /mogas, never had any more trouble. The 150/150 conversion uses an engine-driven fuel pump as well as an electric boost pump. Mine was plumbed in series, per the STC, but since I sold the airplane I've talked to a couple guys whose fuel pumps were plumbed in parallel, possibly to avoid / eliminate the possibility of vapor lock.

To my knowledge there is no winter avgas blend. It is not needed as the temperature extremes can be present year round with airplanes and it is already built into the fuel specification.

I have run E0 mogas for several winters now in my O-320 and have not noticed any difference.

akray wrote:So since this is my first winter owning a airplane I am starting to wonder about our winter fuel. I have seen in the last couple of weeks my fuel mileage in my truck is going down so we must have switched to winter blend fuel at the pumps. Is there a winter blend av gas? does the winter blend auto fuel have any adverse affects running in our planes? I have auto fuel STC for my o-300, just want to know if im going to have any problems this winter with it.

You probably already know this, but since you are new to ownership, be aware that you can't just tanker fuel from your friendly local Shell or Conoco station and put it in your airplane. Mogas for airplanes mustn't have any of the additives mandated for pollution control of automotive exhaust emissions. So aviation grade mogas is different from automotive grade mogas. Your STC only covers using aviation grade mogas.

Cary

What's your source? I use E0 autofuel from my local station and know plenty of people that do the same. If you read the STC is does not prohibit brands or only allow "aviation grade" auto fuel. There is an minimum octane requirement and I wouldn't run a winter blend in the middle of the summer, but the whole point of the STC is to allow one to burn ethanol-free AUTO fuel.

Cary wrote:You probably already know this, but since you are new to ownership, be aware that you can't just tanker fuel from your friendly local Shell or Conoco station and put it in your airplane. Mogas for airplanes mustn't have any of the additives mandated for pollution control of automotive exhaust emissions. So aviation grade mogas is different from automotive grade mogas. Your STC only covers using aviation grade mogas.

Cary

I've never heard of aviation grade mogas.

I use E0 93 octane I get at a Conoco.

Cary wrote:

akray wrote:So since this is my first winter owning a airplane I am starting to wonder about our winter fuel. I have seen in the last couple of weeks my fuel mileage in my truck is going down so we must have switched to winter blend fuel at the pumps. Is there a winter blend av gas? does the winter blend auto fuel have any adverse affects running in our planes? I have auto fuel STC for my o-300, just want to know if im going to have any problems this winter with it.

You probably already know this, but since you are new to ownership, be aware that you can't just tanker fuel from your friendly local Shell or Conoco station and put it in your airplane. Mogas for airplanes mustn't have any of the additives mandated for pollution control of automotive exhaust emissions. So aviation grade mogas is different from automotive grade mogas. Your STC only covers using aviation grade mogas.

Cary

you may not be able to where you are located at. But I actually can and DO, fill up my transfer tank at my local shell station and fill straight into my plane. Here in Alaska we do not have the additives and shit in our fuel like you do in the states. aviation grade mogas?? never heard of it, no ethanol here

scottf wrote:What's your source? I use E0 autofuel from my local station and know plenty of people that do the same. If you read the STC is does not prohibit brands or only allow "aviation grade" auto fuel. There is an minimum octane requirement and I wouldn't run a winter blend in the middle of the summer, but the whole point of the STC is to allow one to burn ethanol-free AUTO fuel.

there is no winter blend in summer anyway, it would be summer, no need for winter blend and not available at the pumps.
I know what my STC says in Alaska we do not have any Ethanol in our fuel. but this time of year there is a "winter blend" till about April. I am just making sure that whatever difference there is in it wont create any problems since I see a decrease in performance in my truck, Maybe ill just use premium for winter time instead of regular unleaded.

I have heard of a winter blend in Diesel fuel, but never in High octane mogas. Have I just not been paying attention?

M6RV6 wrote:I have heard of a winter blend in Diesel fuel, but never in High octane mogas. Have I just not been paying attention?

X2

Our winter blend here in NH used to have MTBE in it. Until they "found out" it was nasty stuff to have leaking into the water supply and banned it. Then they used ethanol for the winter blend. And now we have ethanol blends year round.

akray wrote:

scottf wrote:What's your source? I use E0 autofuel from my local station and know plenty of people that do the same. If you read the STC is does not prohibit brands or only allow "aviation grade" auto fuel. There is an minimum octane requirement and I wouldn't run a winter blend in the middle of the summer, but the whole point of the STC is to allow one to burn ethanol-free AUTO fuel.

there is no winter blend in summer anyway, it would be summer, no need for winter blend and not available at the pumps.
I know what my STC says in Alaska we do not have any Ethanol in our fuel. but this time of year there is a "winter blend" till about April. I am just making sure that whatever difference there is in it wont create any problems since I see a decrease in performance in my truck, Maybe ill just use premium for winter time instead of regular unleaded.

Premium is just higher octane, worthless unless you need it due to higher compression ratio. Most low-compression aviation engines were built to run on 80/87 octane, so 87 octane will do just fine if that meets your STC qualifications.

As for running winter blend in summer, I was meaning more like for some reason you had to let your airplane sit for a long time and had a winter blend in the tanks on a hot summer day. If you fly frequently it will never be an issue. Just fill up with E0, fly frequently, and enjoy the savings.

M6RV6 wrote:I have heard of a winter blend in Diesel fuel, but never in High octane mogas. Have I just not been paying attention?

Yes there is such thing as winter blend gasoline. It has a higher RVP to allow the fuel to evaporate at low temperatures. What is uncertain is when and which stations switch as they don't advertise it. I suspect it is a bigger factor for carb'd engines because fuel injected engines don't care too much... and even then only in extremely cold temps. The higher RVP would increase the probability of vapor lock if run in warm temperatures.

Ray, I wouldn't worry about it. I don't see any change in my AV gas like we do in our auto gas in winter. I noticed I'm dropping mpg in my pickup to in the last week. Where are you buying? Airport? Essential 1?

For any AV I buy its at essential one and mix with auto fuel. other then that I fill up at shell or chevron. I just wanted to make sure our winter blend auto fuel wasnt going to be a problem in the plane, since it drops performance and mpg in our vehicles I wouldnt want to drop any performance in the air