summer vs winter gasoline

[DavisM38]

I`m guessing some of you know about gasoline. I want to get a 250 gal. farm tank filled with gasoline while prices are low. My question is, do I get summer gas or wait for winter blend? Does anyone know what`s the difference between them? I want to use it all year, this winter and next summer in my mvs, old snowmobile, boat, 4 wheeler, lawn mower, tractor etc.

 

[cbear]

Around our parts, summer blend is E10 with volatile additives to reduce smog. Winter blend is just E10.

 

[m16ty]

I think the only thing different in the summer and winter blend has to do with emissions. For your situation, I'd just buy it when the price is low and not worry what blend it is.

 

[royalflush55]

I would only buy 100% gas for long term storage. It should cost about 20 cents more a gallon but it's worth it. E10 has a shelf life of about 90 days after it's blended before it starts to separate. I do not recommend putting E10 in anything that sets any amount of time. Be good to your engines!

 

[Karl kostman]

I would second what royalflush55 said stay away from any Ethanol if possible for any kind of storage, if you have never heard of PHASE SEPARATION that is a very good thing and I suggest you try hard to keep it that way! If you do have to get some with Ethanol in it then get the lowest levels that you can and your going to have to put some really good preservative in with the gasoline, I only store Diesel fuel and its a whole lot more forgiving than Gasoline for storage!
KK

 

[cbear]

I would only buy 100% gas for long term storage. It should cost about 20 cents more a gallon but it's worth it. E10 has a shelf life of about 90 days after it's blended before it starts to separate. I do not recommend putting E10 in anything that sets any amount of time. Be good to your engines!

I agree, if that's an option. You don't want the alcohol pulling in moisture.
100% gas is not available in my area.

 

[74M35A2]

Thread several months old, but the difference between summer and winter gasoline is the vapor pressures. For what you are doing, you won't notice the difference.

Gasoline if vented to the air starts to degrade at about 6 months. At one year, it is borderline yucky. Stale fuel will be difficult or not start, but sometimes can be ok once the engine is started with ether.

You out can easily dispose of stale fuel by mixing it with fresh and consuming in your engine.

 

[steelypip]

I'll go ahead and put in a couple more cents worth as I used to do lab work with gasoline. Gasoline is a mixture of hundreds of different hydrocarbon compounds. Pump automotive gasoline usually has ethanol and some detergents added as well. As 74M35A2 said, the difference between summer and winter blend is in the vapor pressure of the mixture, and this is achieved by adding proportioinately more low boiling point compounds in the winter blend, and more high boiling point compounds in the summer blend. It used to be a lot bigger deal when everything had carburetors - too high a vapor pressure results in vapor lock and carburetor fires. Too low a vapor pressure makes for hard starting in winter. Fuel injected engines are much less sensitive to these differences, so we can often get away with out of season fuel much more easily.

Ethanol always seems to encourage biology to happen in gasoline, both because it entrains water and because there are microorganisms everywhere that digest ethanol (thanks for nothing, midwestern corn farmers). I'd do whatever was necessary to avoid getting E10. For long term storage you will need to add an antioxidant/biocide containing EDTA - probably a lot of it. Store it as cool as possible (underground/basement is ideal) and with an airlock as used in wine and beer fermentation with the airlock fluid being oil plus biocide. Back in the bad old days gasoline came with lots of tetraethyl lead in it, which is an excellent biocide, but it is also unfortunately bad for humans and catalytic converters.

As for what to store, I would definitely lean toward a summer blend, as lower vapor pressure fuels are less prone to boil off in hot weather and won't have the vapor lock problems you can get with winter blend fuel in summer. As diesel folks can tell you, diesel fuel keeps a lot longer than gasoline does, and part of that is due to the lower vapor pressure of the fuel.

If you want to use the stored summer blend fuel in winter, I would recommend freshening it by adding 10% of recent winter blend fuel to the engine's fuel tank if you experience starting problems. All you need is a high vapor pressure component to get the cold engine to catch and run. A shot of ether would work as well.

 

[gimpyrobb]

I agree, if that's an option. You don't want the alcohol pulling in moisture.
100% gas is not available in my area.

There is a couple:

http://pure-gas.org/index.jsp?stateprov=OH