does gas lose its octane after storage?

Type-Rare#1248 · 01-30-2005, 01:11 PM

Hey guys,
my car had been in storage for the past month or so and I just brought it back out this weekend. My car had been tuned to run on 94 octane gas. When I first brought it out, the car seemed a lot slower than before. Could it be because of the old gas in the car? I am currently running hondata, adjustable fuel pressure regulator...could anything have gone wrong with them during my storage?

another question is whether different temperatures would cause changes to a car's air fuel ratio? for example, if the air is colder outside, there would be more oxygen in your combustion chamber and therefore require more fuel to combust. If you keep the same amount of fuel, then the car would run lean. Is there anything wrong with my reasoning?

TIA

1999all_motoR_teg · 01-30-2005, 01:14 PM

Yes gas does start to lose it's octane rating after about 2 weeks. When storing a car it's a good idea to go to any auto store and purchace a bottle of Sta-bil. It is a fuel stabilizer and will help keep the gas "fresh" for I believe the bottle says 12 months

nightrider · 01-30-2005, 03:20 PM

go with the sta-bil as suggested.

vtec.dc2 · 01-30-2005, 03:23 PM

Quote:

Originally Posted by 1999all_motoR_teg

Yes gas does start to lose it's octane rating after about 2 weeks. When storing a car it's a good idea to go to any auto store and purchace a bottle of Sta-bil. It is a fuel stabilizer and will help keep the gas "fresh" for I believe the bottle says 12 months

2 weeks? really? how much of its rating does it loose within 2 weeks?

Opie · 01-30-2005, 03:24 PM

LOL

Opie, sits back and waits for formula

Combustion Contraption · 01-30-2005, 04:04 PM

No way its 2 weeks, i would say more like 2 months.

nemesis0104 · 01-30-2005, 09:23 PM

Gasoline life varies on where it's stored, how much is stored, and weather conditions...Gasoline can last around 3-6 months..depending on those variables...so if you plan to store you car, just run your car down to a 1/4 tank...do a double dose of STABIL Fuel Stablizer and you won't have to worry about stale or gummy gas...

double dose will allow the gas to stay fresh for 2 years..

Since you car seems sluggish, just go fill it up and run it down to 1/2 tank and refill it again...it should dillute the old gas...hope that helps...

1999all_motoR_teg · 01-31-2005, 02:21 AM

Quote:

Originally Posted by opie

LOL

Opie, sits back and waits for formula

Well the formula is X molecules and Z temperature...LOL J/K

I've heard that it starts to loose it's rating after 2 weeks, guess I was wrong LOL

Type-Rare#1248 · 01-31-2005, 03:45 PM

thx for the reply guys

is there anyone who could answer the second part of my question?

visi0n · 01-31-2005, 04:24 PM

...octane is lost when light hits it for a large amount of time.

you will loose more octane storing your gas in a container than while in your gas tank.

as far as air fuel ratio goes...colder fuel = denser fuel so yes, you will run a tad more richer when colder, but colder fuel with colder air will almost equate out to equal the same air fuel ratio. stock computers have this compesation mapped out into its computer, so you should have around the same air fuel regardless of temp. maybe a difference of 0.1 or 0.2 air fuel when its colder outside or you have colder fuel.

vtec.dc2 · 02-01-2005, 03:07 AM

Quote:

Originally Posted by visi0n

as far as air fuel ratio goes...colder fuel = denser fuel so yes, you will run a tad more richer when colder, but colder fuel with colder air will almost equate out to equal the same air fuel ratio. stock computers have this compesation mapped out into its computer, so you should have around the same air fuel regardless of temp. maybe a difference of 0.1 or 0.2 air fuel when its colder outside or you have colder fuel.

its the other way around. where do you get your information? a/f will be more lean during winter time, i had mine tuned during winter so its safe all year long. change isn't dramatic so its drivable all year long. while rsx has this feature (using several maps based on temps), ours adjust for idle/startup, closed loop will will always adjust to 14.7 but wot will lean out during colder temps. for n/a application there isn't much to worry about unless you have higher flowing exhaust setup (header/cat/catback) and intake allowing more air and leaning out. mine dynoed in 14's a/f w/ stock ecu during winter (thats with i/h/e).

Chris F · 02-01-2005, 07:24 AM

Quote:

Originally Posted by visi0n

as far as air fuel ratio goes...colder fuel = denser fuel so yes, you will run a tad more richer when colder, but colder fuel with colder air will almost equate out to equal the same air fuel ratio.

Quote:

Originally Posted by vtec.dc2

its the other way around. where do you get your information? a/f will be more lean during winter time, i had mine tuned during winter so its safe all year long. change isn't dramatic so its drivable all year long. while rsx has this feature (using several maps based on temps), ours adjust for idle/startup, closed loop will will always adjust to 14.7 but wot will lean out during colder temps. for n/a application there isn't much to worry about unless you have higher flowing exhaust setup (header/cat/catback) and intake allowing more air and leaning out. mine dynoed in 14's a/f w/ stock ecu during winter (thats with i/h/e).

pwned by empirical gas laws.. PV=nRT for an ideal gas.
Charles' Law:
V/T = k .. so absolute temperature decrease means volume decreases (proportionally)

The difference between a hot (30 C) day and a cold (0 C) day is a 10% reduction in volume for the air, the density is higher by about 10% too. The gas will contract a LOT less than that (when's the last time you saw a 5 gallon container of gas shrink to 4.5 gallons in the winter? Me neither, but I've seen it happen to empty containers.

RGoose18 · 02-01-2005, 07:27 AM

Wow, a lot of ppl w/ a lot of damn OPINIONS and a ton of misinformation.

vtec.dc2 · 02-01-2005, 07:47 AM

Quote:

Originally Posted by Chris F

The difference between a hot (30 C) day and a cold (0 C) day is a 10% reduction in volume for the air, the density is higher by about 10% too.

i said nothing about gas. air is more dense during winter and will raise a/f ratio a bit.

Chris F · 02-01-2005, 07:53 AM

Quote:

Originally Posted by vtec.dc2

i said nothing about gas. air is more dense during winter and will raise a/f ratio a bit.

I was trying to agree with you!! I just added that bit about the gas because it "does" contract just a little bit.

Chris F · 02-01-2005, 08:30 AM

If you're worried about octane, you can toss a gallon or two of Toluene/Xylene in your gas tank (about 118 octane) from a paint store. You can find it for $5-$6 a gallon if you look.
That is, if you're too impatient to burn off your current tank

http://www.honda-tech.com/zerothread?id=1032265
-Chris

01-30-2005, 01:14 PM	#2
1999all_motoR_teg Honda-Tech Member Garage is empty, add now Join Date: Sep 2002 Location: all motor Toronto Canada, Canada Posts: 970 iTrader Rating: (0)	Re: does gas lose its octane after storage? (Type-Rare#1248) Yes gas does start to lose it's octane rating after about 2 weeks. When storing a car it's a good idea to go to any auto store and purchace a bottle of Sta-bil. It is a fuel stabilizer and will help keep the gas "fresh" for I believe the bottle says 12 months __________________ http://www.defcon-racing.com 1999 K24/K20A DC2 roadrace car......driver/owner 2000 Honda Civic Hatch roadrace car.....co-driver

01-30-2005, 03:20 PM	#3
nightrider Honda-Tech Member Garage is empty, add now Join Date: Sep 2002 Location: Seattle, Wa, USA Posts: 4,079 iTrader Rating: (0)	Re: does gas lose its octane after storage? (Type-Rare#1248) go with the sta-bil as suggested. __________________ 92 Civic Si '00 FBP ITR #1526 rockin' the JDM front-end. sold

01-30-2005, 04:04 PM	#6
Combustion Contraption Honda-Tech Member Garage is empty, add now Join Date: Jan 2003 Location: So Cal Posts: 10,171 iTrader Rating: (0)	No way its 2 weeks, i would say more like 2 months. __________________ EARL LASKEY, YOU WILL BE MISSED CCCylinderheads.com

01-30-2005, 09:23 PM	#7
nemesis0104 Garage is empty, add now Join Date: May 2004 Location: VTECing, mi, us Posts: 684 iTrader Rating: (0)	Re: (LsVtec92Hatch) Gasoline life varies on where it's stored, how much is stored, and weather conditions...Gasoline can last around 3-6 months..depending on those variables...so if you plan to store you car, just run your car down to a 1/4 tank...do a double dose of STABIL Fuel Stablizer and you won't have to worry about stale or gummy gas... double dose will allow the gas to stay fresh for 2 years.. Since you car seems sluggish, just go fill it up and run it down to 1/2 tank and refill it again...it should dillute the old gas...hope that helps... __________________ 95' MILANO RED GSR - R.I.P. 4-29-04 01' NIGHTHAWK BLACK PEARL ITR 01' KAISER SILVER METALLIC K20A2 POWERED ITR.... MY KAAA [url="http://www.honda-tech.com/garage?cmd=viewcar&id=2276"]http://www.honda-tech.com/gara...=2276[/url]

01-31-2005, 03:45 PM	#9
Type-Rare#1248 Garage is empty, add now Join Date: Dec 2001 Location: Vancouver, BC, Canada Posts: 1,547 iTrader Rating: (0)	Re: does gas lose its octane after storage? (Type-Rare#1248) thx for the reply guys is there anyone who could answer the second part of my question? __________________ "It's not how hard you push along the way; it's having something in you to finish." -Michael Jordan Jun III Cams / Valve Springs / Retainers / Spoon Cam Gears CTR Pistons Jun Header / Renault Cat / T1R B-Pipe / Spoon N1 Exhaust AJR Ported TB / Comptech Icebox / K&N Air filter Hondata S100 T1R Lightweight Battery Fidanza Flywheel / Exedy Clutch / Endless Na-M Break Pads / SS Brake-lines 15" Racing Hart CP-035 / Falken Azenis / Buddy Club Racing Spec Dampers

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01-30-2005, 01:11 PM	#1
Type-Rare#1248 Garage is empty, add now Join Date: Dec 2001 Location: Vancouver, BC, Canada Posts: 1,547 iTrader Rating: (0)	does gas lose its octane after storage? Hey guys, my car had been in storage for the past month or so and I just brought it back out this weekend. My car had been tuned to run on 94 octane gas. When I first brought it out, the car seemed a lot slower than before. Could it be because of the old gas in the car? I am currently running hondata, adjustable fuel pressure regulator...could anything have gone wrong with them during my storage? another question is whether different temperatures would cause changes to a car's air fuel ratio? for example, if the air is colder outside, there would be more oxygen in your combustion chamber and therefore require more fuel to combust. If you keep the same amount of fuel, then the car would run lean. Is there anything wrong with my reasoning? TIA __________________ "It's not how hard you push along the way; it's having something in you to finish." -Michael Jordan Jun III Cams / Valve Springs / Retainers / Spoon Cam Gears CTR Pistons Jun Header / Renault Cat / T1R B-Pipe / Spoon N1 Exhaust AJR Ported TB / Comptech Icebox / K&N Air filter Hondata S100 T1R Lightweight Battery Fidanza Flywheel / Exedy Clutch / Endless Na-M Break Pads / SS Brake-lines 15" Racing Hart CP-035 / Falken Azenis / Buddy Club Racing Spec Dampers

01-30-2005, 03:24 PM	#5
Opie Garage is empty, add now Join Date: Aug 2003 Location: Warning, gRand Return imminent,, NY, USA Posts: 10,172 iTrader Rating: (0)	LOL Opie, sits back and waits for formula

01-31-2005, 04:24 PM	#10
visi0n Honda-Tech Member Garage is empty, add now Join Date: Aug 2001 Posts: 678 iTrader Rating: (0)	...octane is lost when light hits it for a large amount of time. you will loose more octane storing your gas in a container than while in your gas tank. as far as air fuel ratio goes...colder fuel = denser fuel so yes, you will run a tad more richer when colder, but colder fuel with colder air will almost equate out to equal the same air fuel ratio. stock computers have this compesation mapped out into its computer, so you should have around the same air fuel regardless of temp. maybe a difference of 0.1 or 0.2 air fuel when its colder outside or you have colder fuel. __________________ -barry

02-01-2005, 07:27 AM	#13
RGoose18 Honda-Tech Member Garage is empty, add now Join Date: Sep 2003 Location: USA Posts: 2,433 iTrader Rating: (1)	Re: (vtec.dc2) Wow, a lot of ppl w/ a lot of damn OPINIONS and a ton of misinformation.

02-01-2005, 08:30 AM	#16
Chris F Senior Member Garage is empty, add now Join Date: Jun 2004 Location: Chicagoland, IL Posts: 10,399 iTrader Rating: (0)	Re: does gas lose its octane after storage? (Type-Rare#1248) If you're worried about octane, you can toss a gallon or two of Toluene/Xylene in your gas tank (about 118 octane) from a paint store. You can find it for $5-$6 a gallon if you look. That is, if you're too impatient to burn off your current tank http://www.honda-tech.com/zerothread?id=1032265 -Chris __________________ Chris Fries - #117 H1 Prelude - now with more VTEC (Thanks [url="http://kingmotorsports.com"]King![/url]) 2007 and 2008 Midwest Honda Challenge H1 Champion Go to Estrada Customs in Libertyville, IL! Great place for any body work!

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does gas lose its octane after storage?