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Sure it is "terrible for gas mileage" but at the price difference per gallon it is a welcomed tradeoff for the results :thumbs:


I personally think it evens out considering you damn near have to fill up twice as often.

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I usually use 87 around town, but when traveling long distances with hilly terrain on the highway, will switch to 93, to prevent knocking and lousy power band.  The truck always seems to run better on the highway, with 93.  

 

Always use Top Tier Gas, as well.   You will pay in the long run, if you do not.  Have not had fuel injection or  emissions issues, following these guidelines.  Make sure you use a good fuel injector cleaner in the gas tank, at least every six months or 6000 miles. Install a good catch can, as well. 

 

Just try different octane ratings, then you will find the octane sweet spot, for your truck.

 

Good luck. 

Edited by Bobbigboy

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My 2015 had a computer average of 19.5, and a Fuelly average (only tracked for the last 8 months of its life) of 19.3.  My 2018 is a 6.2L, and I have yet to refuel it, since I bought it (Saturday, 15 September).  So far, the computer is showing that I’m averaging 13.2, for this tank, so far.

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On ‎9‎/‎14‎/‎2018 at 10:39 AM, medic717 said:

Opinions are something everyone has I guess but I am with you on the 89. Black Bear Tuning recommends a minimum of 89 on a stock tune in our trucks with the 5.3. From my understanding they recommend this because while doing tuning they have noticed retarding of the timing and engine knock while on their computers. Their explanation of why this is makes sense to me. Our engine has a 11:1 compression ratio. Higher compression engines need a more controlled burn which means a higher grade of fuel. Agree or disagree for the difference I will stick with 89.

Interesting note now that you've brought it up. Fuel doesn't care what the mechanical compression ratio of a motor is. It cares what the peak cylinder pressures are. These are indicated by the brake mean effective pressure. Motors with VVT/VVL can just as easily delay the intake closing angle as remove spark timing to kill off knock. Tuners find spark a more convenient handle to pull upon. Part throttle MAP is another handle. This is controlled on the build sheet when you order your final drive gearing or when you select tire height. Spark timing, mechanical compression ratio or throttle angle controlled by load (effective gear) all have the same effect. They reduce BMEP below the knock threshold.  At high elevations BMEP is limited by elevation moderated atmospheric pressure. It's why gasoline suppliers in places like Denver and Salt Lake supply stations with overall lower octane fuels. 

 

All motors need a controlled burn regardless of their compression ratio. Uncontrolled burn is the definition of knock. Knock sensor retard is not evil. In fact the fact it is used means the original spark tables are leaving nothing on the table. That can't be said of a tune whose spark map is so retarded that in never asks for KR. That tune is always leaving something on the table.    :seeya:

Edited by Grumpy Bear

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I’ve read lots of opinions on gas blends. I have 5 vehicles that get driven, some less than others. I have two lawn mowers that sit for at least 5 months in the winter with one tank of gas. My wife’s Acura intagra type R, one maybe two tanks of gas a year. My 92 truck maybe 4 tanks of gas. We’ve had the Acura 18 years the truck 8 years using no additional additives. Never had a water in gas problems, I can’t just be lucky.


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43 minutes ago, Grumpy Bear said:

Interesting note now that you've brought it up. Fuel doesn't care what the mechanical compression ratio of a motor is. It cares what the peak cylinder pressures are. These are indicated by the brake mean effective pressure. Motors with VVT/VVL can just as easily delay the intake closing angle as remove spark timing to kill off knock. Tuners find spark a more convenient handle to pull upon. Part throttle MAP is another handle. This is controlled on the build sheet when you order your final drive gearing or when you select tire height. Spark timing, mechanical compression ratio or throttle angle controlled by load (effective gear) all have the same effect. They reduce BMEP below the knock threshold.  At high elevations BMEP is limited by elevation moderated atmospheric pressure. It's why gasoline suppliers in places like Denver and Salt Lake supply stations with overall lower octane fuels. 

 

All motors need a controlled burn regardless of their compression ratio. Uncontrolled burn is the definition of knock. Knock sensor retard is not evil. In fact the fact it is used means the original spark tables are leaving nothing on the table. That can't be said of a tune whose spark map is so retarded that in never asks for KR. That tune is always leaving something on the table.    :seeya:

This man knows whats up 

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I run E85 as much as I can and the truck loves it. I definitely notice the increased power and overall better driving experience. When I first started using E85, I confused the “85” as an octane rating as opposed to the percentage of Ethanol. After driving around for a while I couldn’t believe the difference so I began reading about why the truck might be driving so much better. I learned E85 has an approximate octane rating of 100-105.

Every so often I put a tank of 87 gasoline in the truck. Gas mileage improves but that doesn’t automatically equate to a lower cost per mile of driving.

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I’d love to try E85 in my new truck, but I’m pretty certain it’s not flex fuel capable.

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50 minutes ago, DirtyAndy said:

I’d love to try E85 in my new truck, but I’m pretty certain it’s not flex fuel capable.

If it is the 6.2, no Dice.

If it is the 5.3 and your gas cap is yellow, Roll away! :thumbs:

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Running E85 in the winter/colder months will result in longer crank times and even more of a mpg loss, based on my experiences.

I stick with 89-91 in the winter.

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I’d love to try E85 in my new truck, but I’m pretty certain it’s not flex fuel capable.
If you truck is capless fuel, there will be a sticker like this on the inside of your fuel door20ff8761b4546ee25924a0e2f976a8eb.jpg

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I run e85 most of the time.  I have been averaging 14.6 mpg hand calculated.  In the colder months I run 89, averaging 18.9 hand calculated.  Around 70% city, 30% interstate driving.

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I don’t think I have that yellow sticker. But, I also haven’t intentionally looked for it. I assumed the e-Assist trucks just weren’t capable.

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The RPO code is FHS. If you look in your top glove box you’ll see your sticker with all the RPO codes that apply to your vehicle. If FHS is there then it’s E85 capable.

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The RPO code is FHS. If you look in your top glove box you’ll see your sticker with all the RPO codes that apply to your vehicle. If FHS is there then it’s E85 capable.

 

Thank you. I’ll take a look tomorrow!

 

Edit: No E-85 for my truck. Fine by me.

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