My experience with Ethanol free gas

Joined
Aug 18, 2009
Messages
4,088
Location
Ohio
We just finally got easy access to "Recreational Fuel" nearby with the opening of two new Sheetz in the area.
Bought two gallons of it yesterday for OPE use.
At $3.42/gal vs. $2.72/gal for RUG, I doubt that my usage of it will expand beyond OPE.
 
Joined
Aug 10, 2017
Messages
338
Location
Iowa
Years ago I tracked several tanks of each and found that E10 gets 3-4% less mpg's but is always a greater % cheaper (in Iowa) than regular. Therefore it's a good value for the cars. Right now there's a 34¢ spread between the 2 which makes the E10 about 12% cheaper. It's more favorable when gas is cheap. The spread doesn't change.
 
Joined
Apr 27, 2010
Messages
5,215
Location
Northeast
Looks like STEWART's purchased a gasoline distributor that carried CITGO , MOBIL and SUNOCO . I think it was back in 2020 . So does that mean all are Top Tier ? Not all STEWART'S show the brand of TOP TIER at the pumps . :unsure:
 

Rochev

Thread starter
Joined
Dec 3, 2016
Messages
238
Location
Maine
I do stick with top tier for my GDI engines. I believe the E0 station is a Citgo but I'd have to double check that as it's just called "Merril's".
 
Joined
Apr 28, 2020
Messages
863
Location
North Dakota
Fortunately I have easy access to E0 in both 87 and 91 grades. Price increase going from E10 to E0 in 87 is 30¢, and then another 20¢ jump for E0 91. I buy the 91 for both vehicles as they both recommend it, and the OPE gets it too since it's easier to fill the jugs same time as the car.
 
Joined
May 6, 2005
Messages
9,188
Location
San Francisco Bay Area
Looks like STEWART's purchased a gasoline distributor that carried CITGO , MOBIL and SUNOCO . I think it was back in 2020 . So does that mean all are Top Tier ? Not all STEWART'S show the brand of TOP TIER at the pumps . :unsure:

It's Top Tier if the branding is Top Tier. That's a requirement for the gasoline brand if (let's say) Mobil is the co-brand. All Mobil stations in the US are required to meet the Top Tier reqreuiements.

All I can find is that Stewart's purchased a company called Red-Kap that includes fuel transportation. Being a wholesaler and distributor doesn't usually mean that they actually have their own fuel facilities. They might have purchase agreements with refiners or purchase their fuel on the spot market where they access fuel transported by pipeline operators. I'd venture that they can use the required Top Tier additives for each brand, which are dispensed at fuel depots.
 
Joined
Aug 20, 2003
Messages
19,241
Location
NE,Ohio
Well yeah, you'll get better mileage without Ethanol in your fuel as you have to burn more than twice the amount of ethanol/methanol to get the same BTUs as gasoline provides. The upside is that ethanol/methanol have higher knock resistance (octane rating) than gasoline when ran at stoichiometric ratios.
your math is off.
IIRC is around 114k btu for gas, and 76k for 100% ethanol.
 
Joined
Oct 23, 2017
Messages
1,102
Location
VA
your math is off.
IIRC is around 114k btu for gas, and 76k for 100% ethanol.
Ok, the point was that he ECU will be shooting for a 14.7:1 air/fuel ratio with pure gasoline and it'll shoot for 14.04:1 on E10
 
Joined
Jun 15, 2003
Messages
38,777
Location
ME
It's my understanding that when ethanol burns, it releases oxygen (that's why it's called an oxygenate) and it's more oxygen than the 21% coming in with the air.

So it is like a very very small nitrous boost, which will increase power, even though it takes more fuel to make it happen.

The statement that "100% pure gas is more dense" is true, but I would not assign "more power" for anything with modern engine controls. Perhaps "more work per gallon" but that's less sexy to read.
 
Joined
Oct 6, 2020
Messages
338
It's my understanding that when ethanol burns, it releases oxygen (that's why it's called an oxygenate) and it's more oxygen than the 21% coming in with the air.

So it is like a very very small nitrous boost, which will increase power, even though it takes more fuel to make it happen.

The statement that "100% pure gas is more dense" is true, but I would not assign "more power" for anything with modern engine controls. Perhaps "more work per gallon" but that's less sexy to read.
In other words Ethanol is a cheap octane booster.
 
Joined
Aug 15, 2021
Messages
144
Location
State
I saw ethanol-free gas for the first time when I went on a trip to Bar Harbor recently. The closest gas station that offers it is 30 minutes away from anywhere I go, but I think it's worth it.

Before I started using it, I always averaged
25-26 mpg and getting about 370 miles a tank during summer.

Now after my second tank of ethanol free gas, in mostly rural driving with the AC always running, I'm getting 27.8 mpg and got 420 miles before the gas light even came on. The butt-dyno says there's a slight increase in torque, but that's not always accurate.

Anyway, is ethanol free a wise choice for a GDI engine? It definitely seems to drive better and is much better efficiency wise, but I'm not sure what difference there is inside the motor.
The butt-dyno. First time I've heard that. I like it.
 
Joined
May 6, 2005
Messages
9,188
Location
San Francisco Bay Area
In other words Ethanol is a cheap octane booster.

It's more than just an octane rating boost. That's part of it. But there's also a cooling effect. It's also more oxygen introduced in a liquid form. It's easy to inject a liquid, but it's much harder to force more air, whether with more valves or forced induction. Of course the fuel and oxygen has to be balanced (neither lean nor rich) but the ECU figures this all out.
 
Joined
Dec 26, 2005
Messages
24,302
Location
Upper Midwest
It's more than just an octane rating boost. That's part of it. But there's also a cooling effect. It's also more oxygen introduced in a liquid form. It's easy to inject a liquid, but it's much harder to force more air, whether with more valves or forced induction. Of course the fuel and oxygen has to be balanced (neither lean nor rich) but the ECU figures this all out.
How does a typical ECU determine if an oxygenated fuel is being used?
 
Joined
May 6, 2005
Messages
9,188
Location
San Francisco Bay Area
How does a typical ECU determine if an oxygenated fuel is being used?

I believe the oxygen sensor reports whether it's lean or rich and the ECU adjusts. I'm not an expert on this, but isn't it a combination of the MAF, MAP, O2, and TPS? But it's not as if there's any way to directly test the fuel.
 
Joined
Dec 26, 2005
Messages
24,302
Location
Upper Midwest
I believe the oxygen sensor reports whether it's lean or rich and the ECU adjusts. I'm not an expert on this, but isn't it a combination of the MAF, MAP, O2, and TPS? But it's not as if there's any way to directly test the fuel.
Oh right I didn’t think about the oxygen sensor, that would explain it. Thanks.
 
Joined
Jun 10, 2002
Messages
3,796
Location
Chattanooga, TN
I have been using 87 octane for a few years now, adds 2-3 mpg on one car, slightly more on my hybrid. 40 cents per gallon over ethanol is the break even point for me. Use it exclusively in mowers, trimmers etc.
 
Joined
Feb 27, 2019
Messages
631
It's my understanding that when ethanol burns, it releases oxygen (that's why it's called an oxygenate) and it's more oxygen than the 21% coming in with the air.

So it is like a very very small nitrous boost, which will increase power, even though it takes more fuel to make it happen.

The statement that "100% pure gas is more dense" is true, but I would not assign "more power" for anything with modern engine controls. Perhaps "more work per gallon" but that's less sexy to read.

But doesn't denser mean more energy? So with more energy per volume, a potential bigger bang with each revolution?

If so, can't the ECU just compensate and bring in more air when on ethanol free fuel for the same quantity of fuel?

(I have no idea, nor hold any expertise whatsoever on the matter).
 
Joined
Aug 23, 2010
Messages
4,050
Location
pa
in my area its almost $1 more but its 93 octane as well, use it in all my small carbd equipment, i even notice using less in my 1 hour self propelled honda mower, seems to run better as well IMO.
 
Top