What fuel for 5.7

[RAM Patriot]

Good afternoon all... New Ram 1500 owner. 2020 Rebel with Rebel Level 2 Equipment Group. 5.7 Hemi. Granite Crystal.

I've read the owner's manual and this thread and I am aware of the 89 octane recommended vs 87 acceptable from Ram. I live in a high mountain town where our fuel options are 85, 87, or 91 ethanol, or 87 or 91 non-ethanol. Suppose I am lazy and I don't want to mix to 91 and 87 to get 89... What grade would you use? 87 or 91 and I prefer non-ethanol.

Note, I exclusively used 87 non-ethanol in my 2012 Ford F-150 Ecoboost this Ram replaced. The mileage difference vs ethanol was noticeable in that truck.

Also note, no gas stations here have non-e 87 or 91 at the same pump. I'd have to fill half at one station and the other half at another station... PITA.

Thanks for the input.

I have used 87 and 90 non-ethanol in my truck.

The truck runs better, stays in ECO mode and gets better gas mileage with the 90 octane.

I would use the 91 octane...

 

[41magmag41]

Id use 91 if the price difference isnt to bad.

 

[arptsprt]

Thanks. It’s only about 14 cents more so about $4.50 more per average tank fill up assuming 31 gals.

Id use 91 if the price difference isnt to bad.

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[Timeless]

I have used 87 and 90 non-ethanol in my truck.

The truck runs better, stays in ECO mode and gets better gas mileage with the 90 octane.

I would use the 91 octane...

Non ethanol should have nothing to do with staying in ECO mode...should just be the octane difference.

@arptsprt it is helpful if you fill out your details and location of your truck...keeps people from asking where you are located.

 

[RAM Patriot]

Non ethanol should have nothing to do with staying in ECO mode...should just be the octane difference.

@arptsprt it is helpful if you fill out your details and location of your truck...keeps people from asking where you are located.

One US gallon of gasoline contains 114,000 BTU of energy;

Ethanol has 76,100 BTU's of energy per gallon.

GGE calculated for gasoline in US gallons at 114000 BTU per gallon​

Fuel: liquid, US gallons	GGE	GGE %	BTU/gal	kWh/gal	HP-hr/gal	kcal/litre
Gasoline (base)[3]	1.0000​	100.00%​	114,000​	33.41​	44.79​	7594.0​
Gasoline (conventional, summer)[3]	0.9960​	100.40%​	114,500​	33.56​	44.99​	7624.5​
Gasoline (conventional, winter)[3]	1.0130​	98.72%​	112,500​	32.97​	44.20​	7496.5​
Gasoline (reformulated gasoline, E10 - ethanol)[3]	1.0190​	98.14%​	111,836​	32.78​	43.94​	7452.4​
Gasoline (reformulated gasoline, ETBE)[3]	1.0190​	98.14%​	111,811​	32.77​	43.93​	7452.4​
Gasoline (reformulated gasoline, MTBE)[3]	1.0200​	98.04%​	111,745​	32.75​	43.90​	7445.1​
Gasoline (10% MTBE)[4]	1.0200​	98.04%​	112,000​	32.83​	44.00​	7445.1​
Gasoline (regular unleaded)[5]	1.0000​	100.00%​	114,100​	33.44​	44.83​	7594.0​
Diesel #2[5]	0.8800​	113.64%​	129,500​	37.95​	50.87​	8629.8​
Biodiesel (B100)[6]	0.9536​	104.87%​	119,550​	35.04​	47.64​	7958.5​
Biodiesel (B20)[5]	0.9000​	111.11%​	127,250​	37.12​	49.76​	8437.7​
Liquid natural gas (LNG)[5]	1.5362​	65.10%​	75,000​	21.75​	29.16​	4943.3​
Liquefied petroleum gas (propane / autogas) (LPG)[5]	1.2470​	80.19%​	91,500​	26.82​	35.95​	6089.8​
Methanol fuel (M100)[5]	2.0100​	49.75%​	56,800​	16.62​	22.28​	3778.1​
Ethanol fuel (E100)[5]	1.5000​	66.67%​	76,100​	22.27​	29.85​	5062.7​
Ethanol (E85)[5]	1.3900​	71.94%​	81,800​	24.04​	32.23​	5463.3​
Jet fuel (naphtha)[7]	0.9700​	103.09%​	118,700​	34.44​	46.17​	7828.9​
Jet fuel (kerosene)[7]	0.9000​	111.11%​	128,100​	37.12​	49.76​	8437.7​

 

[SpeedyV]

One US gallon of gasoline contains 114,000 BTU of energy;

Ethanol has 76,100 BTU's of energy per gallon.

GGE calculated for gasoline in US gallons at 114000 BTU per gallon​

Fuel: liquid, US gallons	GGE	GGE %	BTU/gal	kWh/gal	HP-hr/gal	kcal/litre
Gasoline (base)[3]	1.0000​	100.00%​	114,000​	33.41​	44.79​	7594.0​
Gasoline (conventional, summer)[3]	0.9960​	100.40%​	114,500​	33.56​	44.99​	7624.5​
Gasoline (conventional, winter)[3]	1.0130​	98.72%​	112,500​	32.97​	44.20​	7496.5​
Gasoline (reformulated gasoline, E10 - ethanol)[3]	1.0190​	98.14%​	111,836​	32.78​	43.94​	7452.4​
Gasoline (reformulated gasoline, ETBE)[3]	1.0190​	98.14%​	111,811​	32.77​	43.93​	7452.4​
Gasoline (reformulated gasoline, MTBE)[3]	1.0200​	98.04%​	111,745​	32.75​	43.90​	7445.1​
Gasoline (10% MTBE)[4]	1.0200​	98.04%​	112,000​	32.83​	44.00​	7445.1​
Gasoline (regular unleaded)[5]	1.0000​	100.00%​	114,100​	33.44​	44.83​	7594.0​
Diesel #2[5]	0.8800​	113.64%​	129,500​	37.95​	50.87​	8629.8​
Biodiesel (B100)[6]	0.9536​	104.87%​	119,550​	35.04​	47.64​	7958.5​
Biodiesel (B20)[5]	0.9000​	111.11%​	127,250​	37.12​	49.76​	8437.7​
Liquid natural gas (LNG)[5]	1.5362​	65.10%​	75,000​	21.75​	29.16​	4943.3​
Liquefied petroleum gas (propane / autogas) (LPG)[5]	1.2470​	80.19%​	91,500​	26.82​	35.95​	6089.8​
Methanol fuel (M100)[5]	2.0100​	49.75%​	56,800​	16.62​	22.28​	3778.1​
Ethanol fuel (E100)[5]	1.5000​	66.67%​	76,100​	22.27​	29.85​	5062.7​
Ethanol (E85)[5]	1.3900​	71.94%​	81,800​	24.04​	32.23​	5463.3​
Jet fuel (naphtha)[7]	0.9700​	103.09%​	118,700​	34.44​	46.17​	7828.9​
Jet fuel (kerosene)[7]	0.9000​	111.11%​	128,100​	37.12​	49.76​	8437.7​

I'm not sure I understand this post. Octane (resistance to detonation) has nothing to do with energy content.

 

[SD Rebel]

I think he means you will get lower mpg with higher ethanol content, even though it has higher octane.

 

[RAM Patriot]

I'm not sure I understand this post. Octane (resistance to detonation) has nothing to do with energy content.

Non ethanol should have nothing to do with staying in ECO mode...should just be the octane difference.

@arptsprt it is helpful if you fill out your details and location of your truck...keeps people from asking where you are located.

I was responding to @Timeless.

Non-Ethanol fuels have more BTU's, therefore the truck has more BTU's available for ECO mode before it has to switch back to 8 cylinders to perform the same amount of work.

 

[SD Rebel]

I was responding to @Timeless.

Non-Ethanol fuels have more BTU's, therefore the truck has more BTU's available for ECO mode before it has to switch back to 8 cylinders to perform the same amount of work.

Oh gotcha!

 

[Timeless]

One US gallon of gasoline contains 114,000 BTU of energy;

Ethanol has 76,100 BTU's of energy per gallon.

​

Correct.

Which should have nothing to do with ECO mode. The engine should produce the same HP/TQ no matter the content mix of the fuel as long as it is the correct octane.

 

[RAM Patriot]

Correct.

Which should have nothing to do with ECO mode. The engine should produce the same HP/TQ no matter the content mix of the fuel as long as it is the correct octane.

Just to put this in perspective for you.

When I switched my gas grill from propane to natural gas I had to put large baffles in because the BTU's were less for the natural gas. Therfore the grill needs to burn more fuel to reach the desired temprature.

Same concept applies to your HEMI. You lower the BTU the engine will require more fuel to accomplish the same RPM.

One cubic foot of propane = 2,516 BTUs compared to one cubic foot of natural gas = 1,030 BTUs.
Propane contains more than twice the energy of natural gas.
In one hour, a 100,000 BTU natural gas furnace burns around 97 cubic feet while a propane furnace burns only 40 cubic feet in an hour.

 

[arptsprt]

Yeah, this day and age considering my job and desires for privacy, I’ll just say I’m located east of Washington state and Oregon, west of NoDAK, SoDak and Nebraska, and north of Nevada, Utah, and Colorado... how’s that? Lol.

My truck lives at 5,900-6,200 ft elevation for its daily life but we often go higher...

@arptsprt it is helpful if you fill out your details and location of your truck...keeps people from asking where you are located.

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[arptsprt]

I’ve never put this much thought into the flippin’ gas that goes into my truck but... next question, lower octane is generally not good due to knocking etc... can higher octane be an issue? I’ve read some sources saying, “whatever you do, don’t go higher than 89!”

I am just planning on 91 non-ethanol at this point.


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[Timeless]

Just to put this in perspective for you.

When I switched my gas grill from propane to natural gas I had to put large baffles in because the BTU's were less for the natural gas. Therfore the grill needs to burn more fuel to reach the desired temprature.

Same concept applies to your HEMI. You lower the BTU the engine will require more fuel to accomplish the same RPM.

One cubic foot of propane = 2,516 BTUs compared to one cubic foot of natural gas = 1,030 BTUs.
Propane contains more than twice the energy of natural gas.
In one hour, a 100,000 BTU natural gas furnace burns around 97 cubic feet while a propane furnace burns only 40 cubic feet in an hour.

So I am totally agreeing with the energy analysis you are saying.

However, ECO mode de-activates cylinders correct? If it is nothing more than that then any combination of fuel that makes the octane needed would be identical to ECO mode.

Now if ECO mode also monitors fuel flow then I can see your points being very relevant.

Yeah, this day and age considering my job and desires for privacy, I’ll just say I’m located east of Washington state and Oregon, west of NoDAK, SoDak and Nebraska, and north of Nevada, Utah, and Colorado... how’s that? Lol.

My truck lives at 5,900-6,200 ft elevation for its daily life but we often go higher...




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So add that then....along with details of the truck you feel comfortable stating (IE, model year/model/engine/ect) Will only help in the future if you need it.

 

[RAM Patriot]

So I am totally agreeing with the energy analysis you are saying.

However, ECO mode de-activates cylinders correct? If it is nothing more than that then any combination of fuel that makes the octane needed would be identical to ECO mode.

Now if ECO mode also monitors fuel flow then I can see your points being very relevant.



So add that then....along with details of the truck you feel comfortable stating (IE, model year/model/engine/ect) Will only help in the future if you need it.

Your truck goes into 4 cylinder ECO mode when engine is not under a load.

Which is usually under 1500 RPMs just above idle.

If the fuel in your truck has more BTU's (energy capacity) then when you step on the accelerator the truck will stay in ECO mode for a longer duration.

When sufficient load is placed on the engine such as going up a slight grade, the engine will switch back to all 8 cylinders.

 

[kenthorkveen]

The time I ran 87 octane, my truck was spark knocking up a storm! (Pinging) so I mixed it with 93, and it cleared up within 10 miles of driving it.. so I don't go any lower than 89 anymore..

 

[Scram1500]

Gasoline degrades over time and the octane rating goes down, specially ethanol gas. Diesel can lose its cetane rating as well, in fact there is a bacteria that will begin to grow in diesel in a few months

Make sure the gas station you go to is a busy one so you don't end up with what's really 85 or 84 octane

 

[Timeless]

Your truck goes into 4 cylinder ECO mode when engine is not under a load.

Which is usually under 1500 RPMs just above idle.

If the fuel in your truck has more BTU's (energy capacity) then when you step on the accelerator the truck will stay in ECO mode for a longer duration.

When sufficient load is placed on the engine such as going up a slight grade, the engine will switch back to all 8 cylinders.

Again I see your logic. However for this to be true it would be based off fuel flow solely or in addition to octane.

My point is no matter the fuel mixture the power of the engine is the same as long as the octane is the same. So ECO mode may be unaffected by the mixture.

I do not know. My only experience is my own truck that goes into ECO mode a lot with an up to E15 mix. There are some stations that sell E free 90 octane but they are at least 20-30 cents more than up to E15 mix 93 octane from Sams/Costco.

 

[RAM Patriot]

Again I see your logic. However for this to be true it would be based off fuel flow solely or in addition to octane.

My point is no matter the fuel mixture the power of the engine is the same as long as the octane is the same. So ECO mode may be unaffected by the mixture.

I do not know. My only experience is my own truck that goes into ECO mode a lot with an up to E15 mix. There are some stations that sell E free 90 octane but they are at least 20-30 cents more than up to E15 mix 93 octane from Sams/Costco.

If you want to experience what I'm talking about you should try running some of the "E free" as you call it fuel through your truck.

It will probably take several tanks to work all of the ethanol fuel out of your system and for your truck to adapt to the new fuel.

Ethanol free fuel is more expensive because ethanol is subsided by your tax dollars.

Federal Subsidies for Corn Ethanol and Other Corn-Based Biofuels | Taxpayers for Common Sense

Taxpayers for Common Sense is an independent and non-partisan voice for taxpayers working to increase transparency and expose and eliminate wasteful and corrupt subsidies, earmarks, and corporate welfare.

www.taxpayer.net

 

[RAM Patriot]

Gasoline degrades over time and the octane rating goes down, specially ethanol gas. Diesel can lose its cetane rating as well, in fact there is a bacteria that will begin to grow in diesel in a few months

Make sure the gas station you go to is a busy one so you don't end up with what's really 85 or 84 octane

Your correct, All fuels will degrade over time especially Ethanol which is also hygroscopic (it attracts water)

Ethanol Faq | Mark's Marine Inc. | Hayden Idaho

Mark's Marine Inc. is a premium marine dealership located in Hayden, ID. We offer boats, pontoons, fishing boats and more from award winning brands such as Avalon, Godfrey, Hewes, Lund, Thunder Jet and Weldcraft with service, parts and financing. We proudly serve the areas of Spokane, Pullman...

www.marksmarineinc.com

You can add stabilizers to help with this hygroscopic process but this will also increase your cost of fuel.

I add PRI-D Diesel Treatment to my tractor especially in the winter months when the tractor is sitting.

It slows down this algae growth and stabilizes the fuel. Made a big difference and I do not get as much soot and smoke when I fire it up.

Amazon.com: PRI - PRI 32-D -D Fuel Stabilizer- for Diesel 32oz: Automotive

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