Do you really need to run super in the 6.4 ?

[drittal]

Running premium won't help and will likely hurt a bit. unless you are tuned properly for the increased octane, you are wasting money.

Mainly I run the 91 instead of 89 because of 1 factor. The Exxon station I use the 87 octane is 10% ethanol, the 91 has none. The 89 is a 50/50 blend of the two. I've known the owners for years. They are like a second family.

 

[Gymkata]

Mainly I run the 91 instead of 89 because of 1 factor. The Exxon station I use the 87 octane is 10% ethanol, the 91 has none. The 89 is a 50/50 blend of the two. I've known the owners for years. They are like a second family.

Oh, ok. I hate ethanol.

 

[WaterBoy1]

From the 2014 manual:

"3.6L/6.4L Engine These engines are designed to meet all emissions regulations and provide excellent fuel economy and performance when using high quality unleaded “regular” gasoline having an octane rating of 87. The use of premium gasoline is not recommended, as it will not provide any benefit over regular gasoline in these engines."

 

[SETEX 6.4]

From the 2014 manual:

"3.6L/6.4L Engine These engines are designed to meet all emissions regulations and provide excellent fuel economy and performance when using high quality unleaded “regular” gasoline having an octane rating of 87. The use of premium gasoline is not recommended, as it will not provide any benefit over regular gasoline in these engines."

Yep.
Exactly what my 2014 manual says.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[KarL45]

have ran the 87 almost always. Even when towing heavy. At one point had to run 85 octane when towing but really didn't see any difference in power. Have also ran 91 a couple of times and again, didn't notice a difference. Will stay with the 87 whenever possible.

 

[smurfs_of_war]

At $.30 per litre (about $1.15/ gallon) more here for 89, I think I am just going to stick with 87. If 87 wouldn't work, there would be a warning right in the manual and on the gas cap/ fuel door.

 

[gustheram]

I ran 87 for the first 5000 miles. Then 89 for the next 8000 miles. Fuel economy was the same. Truck seemed to run smoother on the 89 than it did on the 87, but only sometimes. Just recently switched back to 87 and haven't noticed a difference yet. For what it's worth, mine is a '15 where the manual says 89 recommended, 87 acceptable.

tl;dr have run both and pretty much no noticeable difference.

 

[outdoorram]

to be honest I really don't think this salemen knows crap anyhow . my wife and I were up at the dealership a week ago to have her grand Cherokee worked on and was talking to him about the new Cherokees hell he didn't even know the right hp between the 3.6l and the 3.2 ! . I asked him how the 2500 leased and he said they don't at all he said that my 1500 quad cab outdoorsman with only 15,000 miles in like new shape was only worth about 18,000 on trade in ! think its time to find a new dealer/salesmen lol

 

[Ryan102]

My book says 87. I run 87

 

[drittal]

My book says 87. I run 87

ryand from the 'river???

 

[68PowerWagon]

Oh, ok. I hate ethanol.

Why is that? I have run it for over 25yrs. (since it has been out) & never had an issues. I remember when it first came out it was clogging up fuel filters because it was cleaning out all of the varnish in the fuel system but don't know why there would be problems now.

 

[danmp]

I always put 91 in my truck. I try few time and I didn't like it. Here the 89 is mixed with the 87 with ethanol. Since the 91 here ( vs the 87 and 89 ) has no ethanol I got better millage on it no so much, but I got some. But the engine run smoother with the 91 especially on the mds.

 

[Dmopar74]

My 2016 6.4 runs like donkey crap on 87, bogs down and is powerless. I decided to try 89 and it's night and day for me. I almost took it to the dealer thinking something was wrong.

 

[loveracing1988]

Why is that? I have run it for over 25yrs. (since it has been out) & never had an issues. I remember when it first came out it was clogging up fuel filters because it was cleaning out all of the varnish in the fuel system but don't know why there would be problems now.

One word. Propaganda.

 

[RoadDog66]

So this thread had me wondering again. So I had $0.80 off/gal for fuel and for fun I ran the tank down to when the Range said "25 miles". I put 26+ gallons of 89 octane in it. So far I'm seeing a full 1 MPG less, yes that's LESS not more than I normally see when using 87 octane. Plus no performance gains that I can discern. This is all doing same daily trip to/from work and same level of force on the gas pedal.

I'm sticking with 87 since it's acceptable by Chrysler standards, my truck likes it better, and it's cheaper

 

[outdoorram]

So this thread had me wondering again. So I had $0.80 off/gal for fuel and for fun I ran the tank down to when the Range said "25 miles". I put 26+ gallons of 89 octane in it. So far I'm seeing a full 1 MPG less, yes that's LESS not more than I normally see when using 87 octane. Plus no performance gains that I can discern. This is all doing same daily trip to/from work and same level of force on the gas pedal.

I'm sticking with 87 since it's acceptable by Chrysler standards, my truck likes it better, and it's cheaper

have you ever run 91 octane ? just wondered how that did if you have .

 

[PippinAin'tEasy]

Gas mileage went in the ******* when I had to go from 89 gas to 89 corn juice. Octanes are all blended with the rm +/-2 at the pump so depending on yer location and station calibration yer no longer splitting hairs, yer splitting already split hairs. 3 words: Lucasoil Fuel Stabilizer.

"Oh, sweet debt. Thy name is Truck."

 

[RoadDog66]

have you ever run 91 octane ? just wondered how that did if you have .

91 is hard to find around here, so 93 is the next up. And at $0.60 -$0.70 more per gallon and as thirsty as the 6.4 is I'm not going into debt filling up each week

 

[theviking]

My 2016 6.4 runs like donkey crap on 87, bogs down and is powerless. I decided to try 89 and it's night and day for me. I almost took it to the dealer thinking something was wrong.

Maybe not to that extreme but I had a similar experience. Runs much better on the higher octanes IMO.