88 Octane 15% ethanol?

[HSKR R/T]

Calm it down boys

 

[Casull]

Just don't like being called a liar or clueless. Shouldn't have to just accept that.

 

[aronSlusa]

first post I read here and wow…


thanks SpeedyV for what you post! first ram coming from a Joop Gladiator and absolutely love it, and we’ll be able to pull the Camaro running *gasp* e85
gonna try the 88 now going forward in the new whip

 

[HSKR R/T]

first post I read here and wow…


thanks SpeedyV for what you post! first ram coming from a Joop Gladiator and absolutely love it, and we’ll be able to pull the Camaro running *gasp* e85
gonna try the 88 now going forward in the new whip

Is the Camaro running E85, or the tow vehicle?

 

[aronSlusa]

Is the Camaro running E85, or the tow vehicle?

Camaro can run a blend or full e85. On track it’s full e, daily driving I’ll mix it up.

 

[FLiPMaRC]

I actually ran 88oct for a few months last year when gas prices were over $4/gal. I was getting 20-22 MPG highway.
Now that local gas prices are around $2.99-3.30, I'm back on 87oct.

 

[RAM_Davis]

Unleaded 88 fuel is spreading in Ohio, but is it good for your car and the climate?

Unleaded 88 fuel gives lower gas mileage than regular unleaded but with fewer carbon emissions. So, should you put it in your vehicle? That depends.

www.dispatch.com

I wanted to look at just the numbers on this, setting aside any other affects (or politics) on performance, etc for a minute. Just raw mpg and how it's priced. Because corn is subsidized (and cheap and domestic) my theory would be that E15 would be cheaper overall. Let's examine the numbers.

"Gasoline produces roughly 43 megajoules of electricity per kilogram, while ethanol produces only 30, meaning pure ethanol achieves lower gas mileage than pure gasoline."

100% gas = 43 MJ/kg
E10 gas (aka 90/10) = (43*.90) + (30*.10) = 41.7 MJ/kg
E15 gas (aka 85/15, aka unlimited 88) = (43*85) + (30*.15) = 41.05 MJ/kg

(41.7 - 41.05) / 41.7 = .0156 or 1.6%. SpeedyV quoted an article that said it was a difference of about 2% which is spot on after rounding. So the answer is you get a 2% loss in MPG. If you averaged about 15 mpg like many do, you'd drop to 14.7 mpg. According to the article, this 15% ethanol gas is 10 cents less on average. If true, that's about an 8% savings on gas. Sheetz is the big supplier of this gas from what i've seen and living in NC they are everywhere.
Now i really doubt that tiny difference would need your truck's computer to do much adjusting. You probably get that much variation regularly buying normal gas since that is all "up to" 10% ethanol. That said, getting 20% worse is very very unexpected. Perhaps this station had water in their E15 or something.

Bottom line, if you wanna save money use the E15 (aka Unleaded 88 from Sheetz) as long as it's 2% cheaper. The article says 5% which may be a good rule of thumb because as we see with anything like this there is expected and then there are real world results.

 

[Eighty]

Unleaded 88 fuel is spreading in Ohio, but is it good for your car and the climate?

Unleaded 88 fuel gives lower gas mileage than regular unleaded but with fewer carbon emissions. So, should you put it in your vehicle? That depends.

www.dispatch.com

I wanted to look at just the numbers on this, setting aside any other affects (or politics) on performance, etc for a minute. Just raw mpg and how it's priced. Because corn is subsidized (and cheap and domestic) my theory would be that E15 would be cheaper overall. Let's examine the numbers.

"Gasoline produces roughly 43 megajoules of electricity per kilogram, while ethanol produces only 30, meaning pure ethanol achieves lower gas mileage than pure gasoline."

100% gas = 43 MJ/kg
E10 gas (aka 90/10) = (43*.90) + (30*.10) = 41.7 MJ/kg
E15 gas (aka 85/15, aka unlimited 88) = (43*85) + (30*.15) = 41.05 MJ/kg

(41.7 - 41.05) / 41.7 = .0156 or 1.6%. Another poster here correctly said it was a difference of about 2% which is spot on after rounding. So the answer is you get a 2% loss in MPG. If you averaged about 15 mpg like many do, you'd drop to 14.7 mpg. According to the article, this 15% ethanol gas is 10 cents less on average. If true, that's about an 8% savings on gas. Sheetz is the big supplier of this gas from what i've seen and living in NC they are everywhere.
Now i really doubt that tiny difference would need your truck's computer to do much adjusting. You probably get that much variation regularly buying normal gas since that is all "up to" 10% ethanol. That said, getting 20% worse is very very unexpected. Perhaps this station had water in their E15 or something.

Bottom line, if you wanna save money use the E15 (aka Unleaded 88 from Sheetz) as long as it's 2% cheaper. The article says 5% which may be a good rule of thumb because as we see with anything like this there is expected and then there are real world results.

You should probably redo the calculations to be based off of volume (not weight). Based on a quick google search, gasoline has a specific gravity of 0.68-0.74, whereas ethanol is 0.79. So a kilogram of gasoline is a different volume than a kilogram of ethanol. And since our trucks inject volumes (not weights), it would make an overall difference in the actual numbers you show above.
I'm too lazy to redo your formulas, so I'll just leave it there.

 

[RAM_Davis]

You should probably redo the calculations to be based off of volume (not weight). Based on a quick google search, gasoline has a specific gravity of 0.68-0.74, whereas ethanol is 0.79. So a kilogram of gasoline is a different volume than a kilogram of ethanol. And since our trucks inject volumes (not weights), it would make an overall difference in the actual numbers you show above.
I'm too lazy to redo your formulas, so I'll just leave it there.

Great catch. However, according to several sources, ethanol is 33% less energy per gallon (or whatever unit of volume), but since it's denatured it becomes about 30% (the denatured solvent is similar to pure gasoline in energy, therefore giving back some energy). The difference between 43 and 30 is 30% so I believe that the math still stands up. I'm new here and new to RAM. I don't even have my truck yet but have lurked here since my Ford was totaled in early August and decided to go with a Ram this time. Once I have my truck I'll certainly test this out in the real world. I'm a geek for data.

 

[FLiPMaRC]

I've been filling up with 88oct from Sheetz @$2.99/gal. I get an extra 0.03c off with the Sheetz app = $2.96/gal. I can only get it when I'm in PA.

It's currently around $3.47/gal in NJ and around $3.55/gal in PA for 87oct.

 

[uncc_99xj]

Unleaded 88 fuel is spreading in Ohio, but is it good for your car and the climate?

Unleaded 88 fuel gives lower gas mileage than regular unleaded but with fewer carbon emissions. So, should you put it in your vehicle? That depends.

www.dispatch.com

I wanted to look at just the numbers on this, setting aside any other affects (or politics) on performance, etc for a minute. Just raw mpg and how it's priced. Because corn is subsidized (and cheap and domestic) my theory would be that E15 would be cheaper overall. Let's examine the numbers.

"Gasoline produces roughly 43 megajoules of electricity per kilogram, while ethanol produces only 30, meaning pure ethanol achieves lower gas mileage than pure gasoline."

100% gas = 43 MJ/kg
E10 gas (aka 90/10) = (43*.90) + (30*.10) = 41.7 MJ/kg
E15 gas (aka 85/15, aka unlimited 88) = (43*85) + (30*.15) = 41.05 MJ/kg

(41.7 - 41.05) / 41.7 = .0156 or 1.6%. SpeedyV quoted an article that said it was a difference of about 2% which is spot on after rounding. So the answer is you get a 2% loss in MPG. If you averaged about 15 mpg like many do, you'd drop to 14.7 mpg. According to the article, this 15% ethanol gas is 10 cents less on average. If true, that's about an 8% savings on gas. Sheetz is the big supplier of this gas from what i've seen and living in NC they are everywhere.
Now i really doubt that tiny difference would need your truck's computer to do much adjusting. You probably get that much variation regularly buying normal gas since that is all "up to" 10% ethanol. That said, getting 20% worse is very very unexpected. Perhaps this station had water in their E15 or something.

Bottom line, if you wanna save money use the E15 (aka Unleaded 88 from Sheetz) as long as it's 2% cheaper. The article says 5% which may be a good rule of thumb because as we see with anything like this there is expected and then there are real world results.

You must be further north in NC than me. No Sheetz in the Charlotte area, as QT has the hold on the large gas station market and they don't offer E88. I used to run it in my F150 when visiting family around GSO and saw no difference, other than less money out of my wallet. I've been tempted to try it in the Ram but haven't yet. Maybe on my next trip.

Sheetz also likes to run specials on E88 from time to time that are significantly cheaper than 87 on certain weekends, usually around holidays. They did this last summer around 4th of July and dropped it to $2.99 when 87 was $4+ everywhere. We were on our way home from a week long trip in VT, and it was a nice savings for sure.

 

[RAM_Davis]

You must be further north in NC than me. No Sheetz in the Charlotte area, as QT has the hold on the large gas station market and they don't offer E88. I used to run it in my F150 when visiting family around GSO and saw no difference, other than less money out of my wallet. I've been tempted to try it in the Ram but haven't yet. Maybe on my next trip.

Sheetz also likes to run specials on E88 from time to time that are significantly cheaper than 87 on certain weekends, usually around holidays. They did this last summer around 4th of July and dropped it to $2.99 when 87 was $4+ everywhere. We were on our way home from a week long trip in VT, and it was a nice savings for sure.

I live near Youngsville, NC which is northeast of Raleigh. Lots of Sheetz around, including one just down the road.

I haven't gotten into the octane threads much, but I do wonder if the "unleaded 88" performs slightly better than the regular stuff at 87. Maybe too little difference to notice, idk.

 

[23RAM]

I haven't gotten into the octane threads much, but I do wonder if the "unleaded 88" performs slightly better than the regular stuff at 87. Maybe too little difference to notice, idk.

I've run 87 and 89 and found no noticeable difference in mileage. Up here I can get 89 with 5% ethanol which means more energy per gallon, so in theory I should get more power and better mileage. Yet I get the same mileage - probable difference is within the margins of error and variable per tank, so I save money and run 87. I'm happy with that.

 

[6of36]

I've run 87 and 89 and found no noticeable difference in mileage. Up here I can get 89 with 5% ethanol which means more energy per gallon, so in theory I should get more power and better mileage. Yet I get the same mileage - probable difference is within the margins of error and variable per tank, so I save money and run 87. I'm happy with that.

Ethanol actually makes more power. But you have to tune for it. Demon 170s, only make over 1,000 HP, on E85.

 

[Jako]

Ethanol actually makes more power. But you have to tune for it. Demon 170s, only make over 1,000 HP, on E85.

Ethanol raises octane but has less BTUs than gasoline.

"Octane ratings are not indicators of the energy content of fuels. (See Effects below and Heat of combustion). They are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner.[5] This is important to know when choosing a fuel for a particular engine. Performance is optimized when the lowest octane rated fuel that can be used without detonation is used.[citation needed]

Where the octane number is raised by blending in ethanol, energy content per volume is reduced."
From
Octane rating - Wikipedia

 

[HEMIJAKE]

Ethanol actually makes more power. But you have to tune for it. Demon 170s, only make over 1,000 HP, on E85.

Ethanol raises octane but has less BTUs than gasoline.

"Octane ratings are not indicators of the energy content of fuels. (See Effects below and Heat of combustion). They are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner.[5] This is important to know when choosing a fuel for a particular engine. Performance is optimized when the lowest octane rated fuel that can be used without detonation is used.[citation needed]

Where the octane number is raised by blending in ethanol, energy content per volume is reduced."
From
Octane rating - Wikipedia

Correct. I probably mentioned elsewhere here, but I had my mustang tuned on e30 and the power increase was outstanding. My mileage took a pretty good hit though. 6-7mpg if I remember correctly. Full e85 was out of the question without an upgraded fuel pump though. I didn't get the fuel pump because it was almost a $2k upgrade, and we only have flex fuel around here (~70%), not true e85.

 

[HSKR R/T]

Correct. I probably mentioned elsewhere here, but I had my mustang tuned on e30 and the power increase was outstanding. My mileage took a pretty good hit though. 6-7mpg if I remember correctly. Full e85 was out of the question without an upgraded fuel pump though. I didn't get the fuel pump because it was almost a $2k upgrade, and we only have flex fuel around here (~70%), not true e85.

Most tuners don't tune for full 85% E85. They know pump gas is inconsistent, and the difference in power from 70% to 85% is negligible. Unless you have a true race car that doesn't see the street much, and you are buying barrels of E85 to fill your tank at home.

 

[RAM Patriot]

To take full advantage of higher blend ethanol fuels you have to change the compression ratio of the engine.

Ethanol has an octane rating of over 100.

Currently, refiners create ‘sub-octane gas,’ which has a lower octane rating than required. Ethanol, is then used to bring the octane rating of the gasoline up to the labelled octane value on the gas pump. For example, 84 octane gasoline is typically blended with 10 percent ethanol to reach the minimum octane requirement of 87 for retail gasoline.

To actualize the full potential of ethanol fuel the engine has to be built around that thermal efficiency.

To do that you need a compression ratio 12:1 to produce a much higher thermal efficiency. Compression ratio is, thus, a key parameter to improve engine thermal efficiency when burning ethanol fuel.

Our engines are not designed to take full advantage of ethanol fuel at 10.5:1 compression ratio.

That is the reason that our manual states not to use E-85 flex fuel or other ethanol blends greater than 15% in your HEMI engine.

 

[HSKR R/T]

To take full advantage of higher blend ethanol fuels you have to change the compression ratio of the engine.

Ethanol has an octane rating of over 100.

Currently, refiners create ‘sub-octane gas,’ which has a lower octane rating than required. Ethanol, is then used to bring the octane rating of the gasoline up to the labelled octane value on the gas pump. For example, 84 octane gasoline is typically blended with 10 percent ethanol to reach the minimum octane requirement of 87 for retail gasoline.

To actualize the full potential of ethanol fuel the engine has to be built around that thermal efficiency.

To do that you need a compression ratio 12:1 to produce a much higher thermal efficiency. Compression ratio is, thus, a key parameter to improve engine thermal efficiency when burning ethanol fuel.

Our engines are not designed to take full advantage of ethanol fuel at 10.5:1 compression ratio.

That is the reason that our manual states not to use E-85 flex fuel or other ethanol blends greater than 15% in your HEMI engine.

Actually, the manual says not to use E85 because these are not flex fuel engines, and the fuel system can't supply enough fuel, and PCM isn't tuned for E85. Has nothing to do with compression ratio of the engine. Ink kw several people running E85 tunes in NA Hemis. But they upgraded injectors and have custom tunes. And they did get an increase in power.

 

[HEMIJAKE]

Most tuners don't tune for full 85% E85. They know pump gas is inconsistent, and the difference in power from 70% to 85% is negligible. Unless you have a true race car that doesn't see the street much, and you are buying barrels of E85 to fill your tank at home.

Solid point, HSKR. I over simplified. I can't speak for other makes or platforms, but in the mustang world at that point, anything over e30 required additional fueling. Typical tuning ratios then were 93 pump, e30, e50, or full e85. From the first tank after I bought it, I ran 93. After about a year I had it tuned for 93 and e30. Tuning for the 93 was eye opening, but e30 was a whole nother level.