Did a quick search and didn't see this addressed.

A friend wants to buy some 107 octane race gas and store it (in regular plastic fuel jugs) for a couple weeks, using it as needed to boost the octane in his tank. (Nearest station selling race gas is 30 miles from him.) The attendant at the station, however, told him that the gas will start "losing octane" immediately and he should try to use it all within a week.

So the main question, of course, is if this is true. Corollary questions, if it is true:
- What causes the octane loss?
- How rapid is the loss?
- Is there any kind of special container to minimize the effect? (I.e., why shouldn't we assume the gas is losing octane while sitting in the pump station reservoir?)
- Will the fuel lose octane sitting in his car's tank?

Thanks for any help,
John

 

I may be wrong on this, but as long as it's sealed in a fuel jug, away for the sun, and as long as it doesn't evaporate, it should be fine. I keep 5 gallon jugs of 110 gas for my race karts for months at a time, and it seems fine. Then again, I do have them mixed w/ 2 stroke engine oil, and I don't know how this would affect the longevity.

 

Wow, how interesting. I use my race fuel immediately upon fill up.

Tan

 

Some guys may also tell you that a white jug will lose octane faster than a red jug. I think that's also bs.

 

Gasoline stored for an extended period of time will form gum without a stabilizer, and may gain some moisture, but I never heard of an octane loss.

 

while the following article doesn't exactly answer the question, its an interesting read:
http://www.howstuffworks.com/question90.htm

But its my understanding that it will lose some octane rating as most gasoline would being stored over a period of time. I'm nots ure about 2 weeks and how much that would make a difference, but at $5 + a gallon, I wouldn't leave it sitting around. So.. inhibitors in the gasoline hold it as best it can to be that octane rating - right? So, it will break down and eventually become something like 93.. 92....91...90....? Is this correct?

Its kind of like an expensive wine bottle not stored properly or stored up straight - you'll end up with an expensive bottle of vinegar after a while.

 

"Prepare to Win" ... that's the only C. Smith book I don't have.

 

OK, I'll play "Refinery Engineer" again .

Most high octane gasolines are made using either a "Reforming" or "Alkylation" process. Both of these processes take short-chain hydrocarbons and join them together to form octane-range fuels. This type of fuel is typically very stable and will hold its composition very well over time (assuming pressurized storage in a opaque container). By pressurized, I mean sealed like any good quality gas can.

However, almost all gasolines contain some "Cracked" gasoline blending components. These are produced using a Fluidized Catalytic Cracking Unit (FCCU), that breaks off parts of long-chain hydrocarbons to form octane range fuels. Cracked gasoline is lower-octane, less stable and tends to want to reform into long-chain hydrocarbons (toward the diesel range) over time. This takes a while to occur, and is sped up with heat and UV radiation.

For example, the US Military stockpiles a lot (a LOT) of motor fuels. There are several refineries in the world that do nothing but re-refine older fuels for the various militaries of the world. In Bahrain, they re-refine the gasoline range fuels for the USofA when the fuel gets 1-2 years old.

Summary: High octane fuels GOOD , low octane fuels BAD , typical storage time LONG , worries FEW .

Regards,

Al

 

I'll just add that I remember reading in a racing periodical (it was probably "RACER") that even a few hours exposure to sunlight (anything less than a perfectly opaque container) will change some chemical properties of gas, including octane. I believe it was UV-related.