Fuel life/Octane loss

[The Rooster]

So living in the snow belt I’m forced to park my gt350 for around 6 months each year. Having a whipple tuned for 94 octane I’m a little concerned about last years gas.
I’m wondering what kind of drop in the octane count you’d see in that timeframe... and aside from not thrashing the car until burning this tank and refilling with fresh gas, should I be dumping in some octane boost for insurance? Or is old gas, old gas? Or am I overthinking the whole thing lol.
Thoughts?

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[spedy7]

Best to use a fuel stabilizer (like Stabil) rather than an octane booster. Ethanol in fuel tends to go bad quickly (~2 weeks?) unlike pure gas (as I have been told).

 

[barstowpo]

Fuel stabilizer will not remedy phase separation which is the problem with ethanol blended fuel. Find some non alcohol fuel for storage.

 

[WildHorse]

Ethanol in fuel tends to go bad quickly (~2 weeks?)

I assure you it does not go bad in 2 weeks, or even 2 months. One of my first jobs was working in a boneyard, every Friday it was 'free fuel up'. I've used gas around a year old. Smelled good, looked good, no Ill effects. I've used bad gas before, believe me you'll know it right away.

 

[spedy7]

I assure you it does not go bad in 2 weeks, or even 2 months. One of my first jobs was working in a boneyard, every Friday it was 'free fuel up'. I've used gas around a year old. Smelled good, looked good, no Ill effects. I've used bad gas before, believe me you'll know it right away.

I stand corrected then

Had to repair an old Dodge van at my last job before dealer work, came in with a no start and no fuel pressure. Dropped the tank and it was just corroded on the inside and reeked of lacquer, definitely sat for a few years.

 

[Angrey]

Fuel doesn't go "bad" in a short amount of time, what happens is the alcohol present is hydrophilic and attracts water. It also tends to separate and layer (which can be remedied easily with sloshing around under driving but upon restart, until it's mechanically worked, it can be a problem).

Fuel stabilizer helps to bind the water and reduce oxidation.

If you haven't added fuel stabilizers and you've let the car sit since "last year" my suggestion would be to drain the fuel. Easiest way to do that is to buy one of the modules that you plug in that tricks your fuel pump into pushing it out at the line connection to the rails.

 

[The Rooster]

The car has sat since October in my heated garage temperature is a constant 65f so condensation would be nonexistent.
Think I’ll put some octane boost in , top it off with some fresh 94 and just be gentle with it for the first tank.... it’s not like it takes long to burn one.

 

[Angrey]

The car has sat since October in my heated garage temperature is a constant 65f so condensation would be nonexistent.
Think I’ll put some octane boost in , top it off with some fresh 94 and just be gentle with it for the first tank.... it’s not like it takes long to burn one.

Not necessarily. All air has moisture in it and over time, the alcohol in the fuel is hydrophilic and pulling the moisture out. It's not as bad as it would be sitting outside, but it's still collecting moisture from the air. Also, the fuel is starting to stratify and separate and over time even with no alcohol will eventually break down into what looks like turpentine and sludge

 

[zzrat]

Angrey, What are your thoughts on a sealed barrel of racing fuel that has never been cracked open for a period of several months since delivered? Could there be an octane loss?
Thanks

 

[WildHorse]

The car has sat since October in my heated garage temperature is a constant 65f so condensation would be nonexistent.

Same here. October till April. Fired it up exhaust smelt normal, decided to log the first hit, knock sensors was happy. This was with Husky 94 E10, which sadly has gone the way of the dodo since Husky was sold.

 

[Bluelightning]

Just fire it up and drive it without going into boost until you run through the rest of the tank, then fill it up with fresh gas and let it rip.

 

[Mrhavasu]

I am not so sure about all this, maybe it has alot to do with where you live. Here in
Kali, our fuel is not so good. I have seen our 91 go bad in as little as 2 weeks in my
dirt bikes. Green corrosion in the carbs. I always buy from high volume brand name stations.
I always run stabilizer and in the toys, add tcw 2 stoke oil. With fuel injection, the fuel is supposed less affected since their is not air to get in the system. The tanks should be better sealed also.
I wish I could get 94 octane here, maybe thats alot better.

 

[The Rooster]

Gas going bad in 2 weeks?? Never heard of that; maybe it’s the heat and humidity in the south?
I use ultra 94 in all my lawn equipment too.. the gas in my tractor still smells as fresh as new and it’s been out in the shed with major temp swings since October too. Not at all concerned with varnishing .... my concern is with how much the octane drops as the gas ages.

 

[Angrey]

This is exactly why they sell ethanol free gasoline, for people to use in their boats and lawnmowers and pressure washers and small engines that get infrequent use.

Ethanol free will last much longer because it's much less hydrophilic, but eventually it layers and lacquers.

The issue is accelerated when you live in any area with high humidity and large daily temperature ranges, which basically acts as a thermal pump as the fuel expands and contracts and pushes vapor in and out of the vent tube

 

[Mrhavasu]

No humidity here, and yes two weeks. Not saying thats the norm but after 30 days , your rolling the dice here, and I am not the only one, my friends experience the same. In CA where I live,
its extremely difficult to find no ethenol gas, or better than 91. And very expensive when you do.
It also gets pretty hot here in the summer and I know that plays a big part. I had gas go bad that
was heavily treated in 4 months in my toyhauler while it was parked in a rv resort in AZ last summer.
Had to drain it out, not real bad, but enough to start jelling in the carb of the Generator. I wish I had your guys fuel here.

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