Still using E15 in today’s trucks?

[Big Mama]

The last thread on this was from 2022.
I recently picked up a Sierra 2500 with the 6.6L gas engine. The mileage is awful. Our area finally got E15 at most stations. It’s 30-40 cents cheaper than 87 octane recommended for my truck.

3 questions:

1) Anyone have problems using E15 long term?

2) Any tips for better mileage. Especially when towing?

3) Why don’t more people use E15?

 

[Coveman]

Ethyl Alcohol is less energy dense than gasoline, which is less energy dense than diesel. The less energy dense, the more you need. That’s part of why e15 yields fewer miles to the gallon.

Alcohol absorbs water so it will pull water out of the air and other liquids. That water then sits in our fuel system and causes chemical reactions (like rust with metal, hardness/brittleness of plastics, etc). Vehicles that are designed for ethanol use materials that are resistant to it.

I prefer gasoline for better milage. I really prefer it for my power equipment that tends to be sensitive to the ethanol.

 

[B-train]

I've run a blend of up to 40% in my DI 6.2L and it doesn't seem to phase it. It actually liked the 20% blend rate, got decent mpg, and still had good power.

I've also run a 20-30% blend in my non-flex 2008 6.2L and it also likes it. I find that if I drive like its 87 octane, then the fuel economy isn't too great, but usually comes in cheaper in cost per mile, not mpg. I've found that with the higher octane of the mix, I can just feather the pedal and it still keeps chugging along. Doing this has gotten me about 18 mpg mostly highway. Mixed driving is about 15.5 or so.

I use my OBD code reader with live data to view the LT fuel trim and can then see what driving style works best and correlate that with the seat of the pants calibration as well.

What are you getting for mpg by the way? Is it brand new, or already broken in with some miles on it?

 

[Fless]

For one thing I would monitor fuel trims with various mixes of ethanol to ensure that the injector metering is keeping up with a greater need for flow (higher ethanol content). Documenting some of the parameters like mpg, Exx mix, etc. would likely give you some better data on what's happening.

I know that @swathdiver has experimented with various ethanol mixes, although his are FF systems.

 

[swathdiver]

All modern vehicles are designed to use E20 now. So E15/88 will work without issue. Probably won't affect the mileage. My FlexFuel trucks got some of their best mileage with an alcohol content between 16-22%.

 

[Big Mama]

I've run a blend of up to 40% in my DI 6.2L and it doesn't seem to phase it. It actually liked the 20% blend rate, got decent mpg, and still had good power.

I've also run a 20-30% blend in my non-flex 2008 6.2L and it also likes it. I find that if I drive like its 87 octane, then the fuel economy isn't too great, but usually comes in cheaper in cost per mile, not mpg. I've found that with the higher octane of the mix, I can just feather the pedal and it still keeps chugging along. Doing this has gotten me about 18 mpg mostly highway. Mixed driving is about 15.5 or so.

I use my OBD code reader with live data to view the LT fuel trim and can then see what driving style works best and correlate that with the seat of the pants calibration as well.

What are you getting for mpg by the way? Is it brand new, or already broken in with some miles on it?

It's brand new. I think I have 1400 miles now since buying it in early August. I'm getting 12 mpg around town but only 9 ish towing, which is the only time it's been on any type of highway so I can't say what it gets on the highway unloaded. My trailer weighs 8k unloaded so I'd say I'm probably around 9k loaded. The longest towing trip so far is about 40 miles but I'm getting ready to go from VA to the Keys. The truck tracks the miles and mpg for each trailer but my boat is only 6k and my utility weighs nothing. Thanks for the help.

 

[Big Mama]

All modern vehicles are designed to use E20 now. So E15/88 will work without issue. Probably won't affect the mileage. My FlexFuel trucks got some of their best mileage with an alcohol content between 16-22%.

Thanks James, I guess, like most things here in southern VA we're a little behind the times. Big Mama used 92 and the wife's 2018 Rav4 uses 87 but we're going to swap it to E15 too when we can find it. We're on the lookout for the blue hoses when we pass by.

 

[Big Mama]

For one thing I would monitor fuel trims with various mixes of ethanol to ensure that the injector metering is keeping up with a greater need for flow (higher ethanol content). Documenting some of the parameters like mpg, Exx mix, etc. would likely give you some better data on what's happening.

I know that @swathdiver has experimented with various ethanol mixes, although his are FF systems.

That's a good idea. It's a little confusing between ethanol levels and octane levels. I read that higher octane levels, 88 vs 87, should equate to better performance and mileage, though I can't see how 1 octane point would change things much. I'll clear my previous mpg data and take good notes on our trip to FL next week.

 

[swathdiver]

That's a good idea. It's a little confusing between ethanol levels and octane levels. I read that higher octane levels, 88 vs 87, should equate to better performance and mileage, though I can't see how 1 octane point would change things much. I'll clear my previous mpg data and take good notes on our trip to FL next week.

Where in Sunshine State are you headed to?

 

[Big Mama]

We’re staying in some state parks on the way to the keys where we’ll park for 4 days to visit the southern most keys. My wife has it all mapped out. I think she mentioned West Palm Beach too. Does 95 go all the way down there?

 

[swathdiver]

We’re staying in some state parks on the way to the keys where we’ll park for 4 days to visit the southern most keys. My wife has it all mapped out. I think she mentioned West Palm Beach too. Does 95 go all the way down there?

When you pass through Port Saint Lucie, give me a wave! LOL

I-95 runs all through Florida until about an hour before the keys, ending in Coral Gables onto US1 and that takes you down through Homestead, through Everglades National Park and on into the keys on US1 still. Always had a good breakfast at the The Stuffed Pig on MM49 in Marathon.

Hey Pete, where do you like to eat down there? @PG01

 

[Big Mama]

When you pass through Port Saint Lucie, give me a wave! LOL

I-95 runs all through Florida until about an hour before the keys, ending in Coral Gables onto US1 and that takes you down through Homestead, through Everglades National Park and on into the keys on US1 still. Always had a good breakfast at the The Stuffed Pig on MM49 in Marathon.

Hey Pete, where do you like to eat down there? @PG01

Thanks brother. I’ve only been to FL via airplane so any tips and landmarks are appreciated. What say you Pete?

 

[swathdiver]

Thanks brother. I’ve only been to FL via airplane so any tips and landmarks are appreciated. What say you Pete?

Depends on time, there's lots to see, too much at once!

We like visiting St. Augustine and Daytona. You can drive your vehicle on Daytona Beach.

If you like aircraft, there's the excellent Valiant Air Command Museum in Titusville, Florida, just a few minutes off I-95. Just to the north is our favorite seafood restaurant, Dixie Crossroads. In that area you have several space museums and of course, Cape Canaveral and Kennedy Space Center. If you time it right, you can see Space-X rocket launches from hundreds of miles away if the weather is clear. See them all the time from my home.

Lots of places to shoot and Florida is back to being an open carry state after 38 years.

Everglades National Park is awesome. Miami Zoo, Monkey Jungle, Gold Coast Railroad Museum, etc. are all down in the Miami area.

If you're feeling adventurous, you can take a boat or plane 67 miles west of Key West to Fort Jefferson in the Dry Tortugas. Always wanted to go there.

On the west coast of Florida, from say Marco Island up to Sarasota, you can often find old shark's teeth on the beach. Some places are better than others to get them.

 

[Big Mama]

Well, we made it to solver springs, which had a nice state park. Our next park was terrible so we’re now is Marathon at a private park which is great. It’s almost empty.

The truck got about 8-9 mpg on the way. I try to drive via the tach vs the speedometer. It hovered around 2k but went to 3k climbing or passing.

Interesting note. Once I unhooked and drove my mpg went to 18 on our drive to and from Key west.

 

[tooleyondeck]

I also have a 2025 HD 6.6L and I am averaging 13-14 combined with about 16hwy, but I don't tow. I wouldn't say it's awful though, I knew what I was buying, and a little more for gas is cheaper than DFM L87 problems lol

I also use 87 Octane, haven't found a benefit to use ethanol or 93 so I'd be interested to hear your experience if you go that route.

 

[Big Mama]

Yeah, same here. I got it bc I needed it. It’s hard finding E15 on this trip. I’m not sure why that is. I’ve been filling up at Luvs or Pilot so you’d think they’d have it.

In Birginia it’s 30-40 cents cheaper which is up to $15 less. I’m tracking mileage several ways so I’ll have some decent data when we get home.