6.4 mpg on 3 hour trip

[65Plymouth]

Cliff notes is the engine adjusts the timing when it senses the 87 octane over the 89 and makes slightly less power. If you tow, you want the 89 octane more than the 87.

As far as mileage, I have seen nothing definitive that gives any increase using 89 over 87 when fuel costs are factored in. For daily driving that does not involve heavy load hauling or towing, 87 is were the math makes sense.

Perfect explanation. Thank you!

 

[drittal]

Cliff notes is the engine adjusts the timing when it senses the 87 octane over the 89 and makes slightly less power. If you tow, you want the 89 octane more than the 87.

As far as mileage, I have seen nothing definitive that gives any increase using 89 over 87 when fuel costs are factored in. For daily driving that does not involve heavy load hauling or towing, 87 is were the math makes sense.

Same here. I fill with 87 unless I'm towing. Then I use premium. If you can find corn free fuel, then it might be worth the extra expense in terms of MPG.

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[gustheram]

Same here. I fill with 87 unless I'm towing. Then I use premium. If you can find corn free fuel, then it might be worth the extra expense in terms of MPG.

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Ethanol-free is available fairly readily around my area but it usually runs about $.75-$1.00 more than regular 87 so the MPG gains probably aren't going to be significant enough to justify spending an additional $20 filling the tank. Not sure about the price differential for others but for me I know it's nowhere near close to worth it.

 

[drittal]

Here, I can get straight 91 for the same price and E10 91. However, out of town I have to look for it usually and the price for 87 straight is about the same as 91 E10, or roughly 30-40 cents above E10 87.

I used to deliver for an Exxon dist., back then E10 was fairly uncommon. Now he can still get straight 91 at the pipeline terminal here, but to get straight 87 for his customers he has to truck it from a refinery over 400 miles away.

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[MN-Ram]

Every vehicle I have ever had got better mpg's with ethanol free gas, but it always cost more. That said, it is definitely not worth it for me to pay 30% more fore fuel to gain 15-20% more mpg's.

I switched from 89 octane to 87 octane on this last tank and I have lost about .5 mpg's, so I might use 87 for driving around, and 89 for towing only. The price difference is about $0.20-0.30 per gallon around me.

 

[skHemi64]

Towing my 3 horse trailer, I've run from Colorado to Maryland and back, then run from Colorado to Orlando and back. Truck likes midgrade for towing. Loses power with low grade gas. No noticeable difference in MPGs, but very noticeable in towing performance. I have a '14 dually 6.4 Hemi. My "old" '14 2500 6.4 Hemi got about 3 mpg better.

Towing I get 7.5 to 10.5 mpg depending on terrain.
Empty I get 14.3 over the life of the truck.

Haven't tried hypermiling the be-jesus out of it over a tank though. Almost bet I could get 18+ with this beast.

 

[MN-Ram]

I just got back from a 320 mile (each way) road trip with my truck. I didn't track my mileage on the way out. However, on the way back my EVIC was showing 20.7mpg. Hand calculated, I was getting 17.7mpg. Not impressed with the EVIC, but that's the best I've seen out of the truck yet. All I had with me was a bed full of camping gear, my wife, and my son.

Oh, and that was running 87 octane and setting cruise at +1 over the speed limit.

 

[Bigdaddy]

17.7 mpg is not bad for a 1 ton hemi, looking at that it's a gas engine that is what I got on the highway for about 100 miles which wasn't all highway.

 

[cash4acres]

Got 25 mpg from Oregon to California on Freeway. Got $1.87 diesel (red). So the cost per mile was: 7.5 cents per mile! $75 per 1000 miles! Now that's cheap....

 

[Rampant]

so what is the general consensus with the 6.4 and Mid grade (89 Octane) vs. Regular? First, does the 6.4 need to be run on 89 oct or is regular ok? And second... Better mileage with 89?

Straight out of the owner's manual...

"6.4L Engine
This engines is designed to meet all emissions regulations and provide sat- isfactory fuel economy and performance when using high quality unleaded gasoline having a posted octane number range of 87 to 89 as specified by the (R+M)/2 method. The use of 89 octane “Plus” gasoline is recommended for optimum performance and fuel economy.

While operating on gasoline with an octane number of 87, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see your dealer imme- diately. Use of gasoline with an octane number lower than 87 can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty.

Poor quality gasoline can cause problems such as hard starting, stalling, and hesitations. If you experience these symptoms, try another brand of gasoline before considering service for the vehicle."

 

[SouthTexan]

Got 25 mpg from Oregon to California on Freeway. Got $1.87 diesel (red). So the cost per mile was: 7.5 cents per mile! $75 per 1000 miles! Now that's cheap....

Why was this posted here when the topic is about the 6.4L?

 

[Hootbro]

Why was this posted here when the topic is about the 6.4L?

Because he is a special needs troll. About the 3rd or 4th thread I have run across with him posting his stupid diesel MPG's when it has nothing to do with the topic at hand.

Also, if you look at the EVIC pictures he posts of his 6.7 Cummins and the super high MPG's, the distance to empty (DTE) mileage is always high showing a fresh refuel and never showing those high MPG numbers with a low DTE that would be more accurate. You can tell the guy goes around after a refuel and DTE/MPG reset coasting and gaming the EVIC for those stupid high numbers nobody else gets with their 6.7 diesel.

 

[EagleChief]

**DISCLAIMER** I did not read through the whole thread.

When I saw the title of your post, I thought you were getting 6.4 MPG's on a 3 hr trip. It took me a minute to figure out you have the 6.4L! LOL!

 

[smurfs_of_war]

I came into this thread thinking "6.4 MPG??? WTF?"

I was pleasantly surprised.

 

[drittal]

Got 25 mpg from Oregon to California on Freeway. Got $1.87 diesel (red). So the cost per mile was: 7.5 cents per mile! $75 per 1000 miles! Now that's cheap....

And illegal.

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