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Whats everybody's thoughts on the stability or freshness that Super-Unleaded would be or will be since the prices are rising? Im guessing that there are less and less amount of people required to run Super and are choosing mid grade or even Regular causing less demand for Super. By the time I buy Super is it really only mid-grade since demand for Super is down? Or is it less than mid-grade? What is the shelf life of Super Unleaded at the pump before additives are required to keep the fuel at 93 octane?
 

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as reported by the major manufactures.......just hear say on my part. gas will start loosing octane rating after 30 days in storage and e10 will go through phase seperation in 60 days in a wet or humid climate. most gas has lost 10% of octane after 60 days of storage and fuel stabilizers only keep the fuel from going to the varnish stage and do NOT retain octane numbers. fresh fuel is the only cure for performance engine. this is just what i have heard in the fuel PROBLEM chat on line. hope this helps.

snivley
 

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Discussion Starter · #3 ·
snivley whiplash said:
as reported by the major manufactures.......just hear say on my part. gas will start loosing octane rating after 30 days in storage and e10 will go through phase seperation in 60 days in a wet or humid climate. most gas has lost 10% of octane after 60 days of storage and fuel stabilizers only keep the fuel from going to the varnish stage and do NOT retain octane numbers. fresh fuel is the only cure for performance engine. this is just what i have heard in the fuel PROBLEM chat on line. hope this helps.

snivley
Thanks Snivley.
Your response brings up fresh fuel.......and is kind of what I was trying to get at..........how do we know how fresh the fuel is before some sort of octane additive needs to be blended in our toys......so we are actually getting the octane the pump says we are buying?
 

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I think 30 days is max now. Even a year or 2 ago it seemed like the crap was degrading after a month or more. My small engines at home were having troubles with older stuff. My new "weed wacker"'s manual stated to use only gas (mixed) less than 30 days old...
 

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This could be a very real problem in many places.

Locally I know 3 stations well enough that if I asked about when and how much premium they've received within 'x' months I'm sure they'd tell me.

Travelling farther away where I don't know who owns/runs the stores I'd possibly stop at, well, you can't expect the guy/gal behind the counter to know.

I would still ask though ! It's not really info that they'd hide or keep from you if they know it.

Last tip: As far as I've seen, most fuel tankers come in to the gas stations in the evening/late evening/night time, so maybe better chance to ask the night crew if you don't know anyone there. If store closes early, than it will be the early AM crew that gets the sheet from the tanker driver.

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I know this sounds weird and it will not tell you what 'octane' the fuel is at or such, but will tell me if it's lost a lot of it's strength- the old wiff test ! If you've ever smelled 1yr old gas vs new gas, you'll know !
 

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I WAS using E10 gas but now tow out of my way to a station that has the old "regular" gas.


My engines are 9.75 compression and need 93 octane. When they were on the dyno, passes were made with both 89 and 93. 89 ran fine up to about 4,000-4,200 then started hitting the knock sensor.

2 hours after installing the engines one of the fuel injectors stopped firing and I lost a motor. It took us 6 weeks to pull it, re-build it, get it back in the boat to re-tune everything. Not trusting it, I had Mark Boos (Precision Marine) fly in to re-tune the motor in my boat on the water.

In the higher RPMs he kept saying it was hitting the knock sensor again.....what changed (I said nothing has). He kept telling me the fuel must be old (I said it's only 6 weeks old!!!). Finally we got a 6 gallon outboard gas can, filled it with fresh fuel, and made another run.....everything was FINE!!!!!

That fuel had lost octane in just 6 weeks!!! Not sure the timeline, but I know E10 goes bad alot FASTER than the old stuff does. (BTW: Speedwake store carries stuff that is supposed to help pass E10 through your engine.)
 

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It depends on octane of fuel and leaded unleaded MTB etc....Our racing fuels products have been tested after a year of dry sealed storage and still shown fine. It depends on if the product is in a dry and sealed storage or an open vented tank etc...I personally didnt do the test but a customer tested our fuel after 2 season and only lost 2 octane, but it was in a dry sealed container....as far as being in gas tanks previous quotes are mostly correct...the ethanol additives are puttin a new spin on everything from shelf life to usefuless in 2 cycle motors so watch out!
 
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