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Run a tank of 91+ in your 6.0.


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I am new to the E.. gas family so I dont really know the benefits yet. So, E85 is 100 octane? Can you mix E with reg gas? Or should you switch all together? Do you have to run your tank dry before switching?

 

E85 is cheaper by me as well, does your 6.0 like it better?

 

This is all new to me...

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E85 is 15% gasoline, so you can mix it with other gasoline. Ethanol blender pumps do that for you if you have access to one. They have E85 in one tank and E10 in another. You select if you want E10, E15, E20, E30, or E85 and it mixes it for you.

 

Ethanol is approximately 105 octane. E85 is indeed around 100 octane.

 

One does not need to run a tank down before switching fuels. They need only to run the vehicle for about 7-10 miles after filling up so the ECM calibration for the new fuel can be adjusted for. Of course, we are talking about flex fuel certified engines.

 

I cannot say the 6.0 in my 2015 or the 5.3 in a previous 1500 did "better" on E85. They have ran just fine either way. I have run several tanks of E10, E15, E20, E30, and E85 and no discernible difference. In doing that, I have established the average mpg from each fuel, so now I can base purchase decisions on taking the price for each fuel at the pump and determining the cost per mile of each fuel. Doesn't change much over short period, mostly seasonal.

 

I haven't seen a power map on the 6.0L that showed it, but the GM map on the 5.3L shows about a 15 hp / 10 lb torque increase using E85.

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E85 is 15% gasoline, so you can mix it with other gasoline. Ethanol blender pumps do that for you if you have access to one. They have E85 in one tank and E10 in another. You select if you want E10, E15, E20, E30, or E85 and it mixes it for you.

 

Ethanol is approximately 105 octane. E85 is indeed around 100 octane.

 

One does not need to run a tank down before switching fuels. They need only to run the vehicle for about 7-10 miles after filling up so the ECM calibration for the new fuel can be adjusted for. Of course, we are talking about flex fuel certified engines.

 

I cannot say the 6.0 in my 2015 or the 5.3 in a previous 1500 did "better" on E85. They have ran just fine either way. I have run several tanks of E10, E15, E20, E30, and E85 and no discernible difference. In doing that, I have established the average mpg from each fuel, so now I can base purchase decisions on taking the price for each fuel at the pump and determining the cost per mile of each fuel. Doesn't change much over short period, mostly seasonal.

 

I haven't seen a power map on the 6.0L that showed it, but the GM map on the 5.3L shows about a 15 hp / 10 lb torque increase using E85.

Wow, thanks for the info. Much appreciated!

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  • 2 weeks later...

So I was reading my manual for other reasons and came across this on page 320: "Because E85 or FlexFuel has less energy per gallon than gasoline, the vehicle will need to be filled more often"

 

Now wouldnt that contradict everything you've said here?

 

If you are paying less for a fuel with less energy (hence cheaper price) AND you are using MORE fuel to do what gasoline would do then how is is more powerful and more efficient? I know you said you dont know the 6.0 facts, but the manual covers ALL engine types. The 5.3 is actally in the 6.2L engine category and 6.0 (mine) is all by itself for some reason.

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Your manual would be correct, but you have to look at the numbers. E85 in my area is going for about $1.55 a gallon. Found it for $1.44 the other day in another town. I know my 2500 averages 11-12 mpg on E85, so at $1.55 a gallon, my cost per mile is about 13.5 cents. Now, let's take premium, which is roughly $2.90 a gallon in my area, I would have to get 21+ mpg avg from my 2500 to just break even on cost per mile. Premium is going to cost me more per mile if say I were to average 15 mpg, which is realistic for my 2500. My fuel cost to use premium would be almost 19.5 cents a mile..... A full 6 cents more cost per mile! So, while I may have to fuel more by using E85, my actual per mile cost is less by a good margin. Simple, eh? I know you could have done the same math if you chose to.

 

So, no contradiction.

Edited by Cowpie
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I guess its all irrelevant for me because I drive my truck like a truck and do not baby it at all. I like to take off quickly to get up to speed and feel the power. I do drive nicely sometimes, but my MPG is at best ave 9 mostly 7 mpg, Obviously you drive conservatively as we all should..lol

 

Eventually i will fill up a tank and see if I can feel the difference

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I drive my semi like a truck also, but I don't like spending more than I have to per mile to operate it. Same for my little 2500. Just curious though, what is the standard for driving a pickup like a truck? Does that mean gross payload and towing all the time? Or does it really mean driving it like a car, say a Camaro?

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The only reason to run 91 or 93 is if you have high compression. Other than that it isn't doing anything for you.

This is exactly true.

It's almost comical to read some of the comments here regarding "better" performance by using premium.

Octane is a burn stabilizing influence when high compression may lead to pre ignition. Other than slowing down the burn in a high compression situation (that doesn't exist in the 6.0L), it does nothing for horse power.

Edited by George C
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This is exactly true.

It's almost comical to read some of the comments here regarding "better" performance by using premium.

Octane is a burn stabilizing influence when high compression may lead to pre ignition. Other than slowing down the burn in a high compression situation (that doesn't exist in the 6.0L), it does nothing for horse power.

You are incorrect with regards to the L96 6.0L At an "effective" 9.7:1 compression ratio my engine had audible preingition when running 87 octane. As stated before, If you can HEAR it its pretty significant. The computer retards the timing as soon as it senses knock. When the computer pulls timing it has a significant effect on how the engine runs. I have been working with GM engines almost my entire life. You can argue with me if you want.... but your wrong.

 

-Eli

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"Wrong". That is an arrogant word is usually used by people who are closed minded and unwilling to consider other variables.

 

What you are experiencing is sub standard gasoline. 87 octane is more than enough to stabilize gasoline for an engine for the 6.0L compression ratio.

In your area, if you need to purchase a higher octane to stabilize a common compression ratio, please do so, but it has more to do with the quality of the product being produced by your local refinery. Your local problem isn't something that affects everyone across this country.

I've never heard my 6.0l knock for a second, no matter how hot or how much demand the engine is experiencing.

Not a peep, and I certainly know what knock sounds like, and I would hear and feel it loud and clear before the ECM retards timing.

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"Wrong". That is an arrogant word is usually used by people who are closed minded and unwilling to consider other variables.

 

What you are experiencing is sub standard gasoline. 87 octane is more than enough to stabilize gasoline for an engine for the 6.0L compression ratio.

In your area, if you need to purchase a higher octane to stabilize a common compression ratio, please do so, but it has more to do with the quality of the product being produced by your local refinery. Your local problem isn't something that affects everyone across this country.

I've never heard my 6.0l knock for a second, no matter how hot or how much demand the engine is experiencing.

Not a peep, and I certainly know what knock sounds like, and I would hear and feel it loud and clear before the ECM retards timing.

 

"It's almost comical to read some of the comments here regarding "better" performance by using premium." That's not arrogant?

 

The very first sentence in my very first post was this...."Results are going to vary based on temp, region and available fuel but give it a try."

 

"I certainly know what knock sounds like, and I would hear and feel it loud and clear before the ECM retards timing." I have years of experience data logging GM cars that I was racing at the track. The computer will introduce "KR" LONG before it can be heard or felt and it makes a significant difference on how the engine performs.

 

My last truck (2008 1500) ran perfectly fine on the same 87 octane from the same station. (BP Top Tier) There was no discernible difference between 91 and 87 in that truck. There is in my HD. That's all that this thread was about.

 

-Eli

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"Wrong". That is an arrogant word is usually used by people who are closed minded and unwilling to consider other variables....

Or, it's just the simple truth.

 

@OP, I've a similar experience, using 91 in my 1500 5.3.

IMO the improvement in the engines performance is most noticeable in the low rpm band.

And that works fine for me since my driving style is very conservative.

 

so long

j-ten-ner

 

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I guess we can all speculate till the cows come home. It's still an engine that doesn't produce enough compression to necessitate a higher octane to stave off pre ignition.

Show me a dyno sheet instead of an opinion, and then you can address who is right or wrong.

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Nobody is talking about dyno sheets and high performance.

But I'm sure that you know what I mean with a "butt-meter".

What I'm talking about is a slight advantage by using higher octane fuel, in only a few driving conditions/situations.

Accelerating in high gears and low rpm while trying to keep the trans from downshifting.

Or inclines, where the trans stays in the sixth gear but it would downshift to the fifth when running 87octane fuel.

 

Will my truck accelerate faster? I doubt it. I also have no measurable gain in mpg.

 

so long

j-ten-ner

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