anyone running NON-OXY premium gas?

illegal2.2 · 12-28-2006, 08:23 PM

from what local subaru members say, it's good for their car. BTW they have mainly wrx. just wondering if running non oxy in MY97 gt will benefit from more gas mileage and power? lmk guys. thanks

choung

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gtwagon941 · 12-28-2006, 08:56 PM

are you talking about fuels like E-85? Never heard of "non-oxy"

iamrazor · 12-28-2006, 11:39 PM

I think you mean oxygenated fuel? That's primarily used in the northern states during winter months for some reason that escapes me at the moment. Sorry, I've been up since 5AM.

generally it drops a few MPG per tank.

ten80 · 12-28-2006, 11:48 PM

They add 10% ethanol to help reduce emissions and the winter "brown cloud" that occurs because of cold air pockets trapping polution. it does reduce your mileage because it is the carbon in gasoline that provides energy for combusition, not oxygen. You will indeed have more power and get higher mpg, however, you shouldn't run premium unless you have high compression or turbo engine. This is because premium has a higher octane rating (more oxygen) and contains less energy for combustion, which is useful for reducing detonation in the applications mentioned. i've been running 85 octane for a while now with no hiccups in my 2.5L impreza- our motors are not very picky!

Wiscon_Mark · 12-29-2006, 12:41 AM

It'll improve MPG because of the items listed about oxygenated gas, but I dunno where you'll find it up here during the winter...

MCarp22 · 12-29-2006, 12:56 AM

Quote:

Originally Posted by ten80

This is because premium has a higher octane rating (more oxygen) and contains less energy for combustion

Octane rating has nothing to do with oxygen content or energy, and everything to do with how much you can compress it before it ignites.

Quote:

Originally Posted by ten80

you shouldn't run premium unless you have high compression or turbo engine.

You don't necessarily need honda-like 11:1 compression to take advantage of premium fuel. I believe some of the DOHC 2.5s took premium from the factory due to aggressive igntion mapping.

Wiscon_Mark · 12-29-2006, 01:04 AM

Quote:

Originally Posted by MCarp22

You don't necessarily need honda-like 11:1 compression to take advantage of premium fuel. I believe some of the DOHC 2.5s took premium from the factory due to aggressive igntion mapping.

Only the 96 GT (and LSi??). And it didn't really make all that much power.

ten80 · 12-29-2006, 01:11 AM

I have to admit that you are correct, octane is C8H18 and has no oxygen content- I'm not sure what I was thinking

. Also, I was misinformed about the energy content. It really depends on the formulation of the gasoline and the ratio of carbon-carbon bonds (high energy) to carbon-hydrogen bonds (low energy). I was correct about ethanol reducing energy yield though

I've not heard of USDM 2.5L dohc needing premium fuel, wich is interesting because subaru's tuning is generally very conservative.

MCarp22 · 12-29-2006, 08:24 AM

Quote:

Originally Posted by Wiscon_Mark

And it didn't really make all that much power.

My neon didn't either.

xcntrk75 · 12-29-2006, 09:12 AM

I avoid it... It's everywhere around me, hard to find non "winter gas" in my crowded area. I avoid it strictly cuz I'm tuned on 93 octane (non ethel) fuel and using it will change my fueling...

12-28-2006, 08:23 PM	#1
illegal2.2 Scooby Specialist Member#: 58329 Join Date: Mar 2004 Chapter/Region: MWSOC Location: MN Vehicle: 97 Legacy GT Rio Red	anyone running NON-OXY premium gas? from what local subaru members say, it's good for their car. BTW they have mainly wrx. just wondering if running non oxy in MY97 gt will benefit from more gas mileage and power? lmk guys. thanks choung * Registered users of the site do not see these ads.

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12-28-2006, 08:56 PM	#2
gtwagon941 Scooby Specialist Member#: 16874 Join Date: Mar 2002 Chapter/Region: NWIC Location: Portland, OR Vehicle: 2008 Audi RS 4 01 Subaru LGT Sedan	are you talking about fuels like E-85? Never heard of "non-oxy"

12-28-2006, 11:39 PM	#3
iamrazor Scooby Guru Member#: 52324 Join Date: Jan 2004 Chapter/Region: NESIC Location: Pelham, NH Vehicle: 2011 SWP WRX LTD 1990 T30 miata	I think you mean oxygenated fuel? That's primarily used in the northern states during winter months for some reason that escapes me at the moment. Sorry, I've been up since 5AM. generally it drops a few MPG per tank.

12-28-2006, 11:48 PM	#4
ten80 Scooby Specialist Member#: 53625 Join Date: Jan 2004 Location: WA Vehicle: 00 EJ205 LGT LTD 97 LGT Wagon	They add 10% ethanol to help reduce emissions and the winter "brown cloud" that occurs because of cold air pockets trapping polution. it does reduce your mileage because it is the carbon in gasoline that provides energy for combusition, not oxygen. You will indeed have more power and get higher mpg, however, you shouldn't run premium unless you have high compression or turbo engine. This is because premium has a higher octane rating (more oxygen) and contains less energy for combustion, which is useful for reducing detonation in the applications mentioned. i've been running 85 octane for a while now with no hiccups in my 2.5L impreza- our motors are not very picky!

12-29-2006, 12:41 AM	#5
Wiscon_Mark Scooby Guru Member#: 94945 Join Date: Aug 2005 Chapter/Region: MWSOC Location: Stevens Point, WI Vehicle: 1995 Legacy OB 5MT 2003 Forester X 5MT	It'll improve MPG because of the items listed about oxygenated gas, but I dunno where you'll find it up here during the winter...

12-29-2006, 01:11 AM	#8
ten80 Scooby Specialist Member#: 53625 Join Date: Jan 2004 Location: WA Vehicle: 00 EJ205 LGT LTD 97 LGT Wagon	I have to admit that you are correct, octane is C8H18 and has no oxygen content- I'm not sure what I was thinking . Also, I was misinformed about the energy content. It really depends on the formulation of the gasoline and the ratio of carbon-carbon bonds (high energy) to carbon-hydrogen bonds (low energy). I was correct about ethanol reducing energy yield though I've not heard of USDM 2.5L dohc needing premium fuel, wich is interesting because subaru's tuning is generally very conservative.

12-29-2006, 09:12 AM	#10
xcntrk75 Scooby Specialist Member#: 60224 Join Date: Apr 2004 Chapter/Region: MAIC Location: NOVA Vehicle: 2008 FXT Sports 2.5 Dark Grey Metallic	I avoid it... It's everywhere around me, hard to find non "winter gas" in my crowded area. I avoid it strictly cuz I'm tuned on 93 octane (non ethel) fuel and using it will change my fueling...