87 vs 89 octane

[KeithP]

2022 5.7: at 18k miles I started experiencing a slight hesitation when accelerating from a dead stop. Didn’t matter if the start/stop feature was on or off. This is my 3rd 5.7 and have always just used 87 octane. Both of the other trucks are still in the family. 17 with my son, 19 with my daughter. I know they both still burn 87 octane with no issues. Dealer tried to tell me it may a transmission shift delay. That didn’t make sense to me. Decided it may be a dirty injector issue so…. simple solutions first. I started burning 89 octane. The hesitation went away about half way through the first tank. Still burning it, running about 50/50 city vs freeway driving and averaging 16 mpg (calculated the old fashioned way). Think I’ll stick with the 89 from now on.

 

[El Guapo Phil]

Very interesting. I been using the 87 and twice a year use Lucas Injector cleaner. Results, no hesitation and burning clean.

 

[BenchTest]

As some others might say, I can go on at length about fuel, quality, and it's storage/dispensing. That was my industry for many years.

Let's start simple - is your truck, by owner's manual showing "Use minimum of 87 Octane Fuel"? If so, your truck should be performing "as normal" with 87 octane. Once we answer that, I have a couple of other ideas.

 

[Burla]

Gotta check the 2022 but all 4 gens were tuned for 89, and indeed mine doesnt like 87 at all just like yours even worse, but hums on 91. Costco only has 87 and 91 here, so I go 91.

 

[Burla]

2022 owners manual. It seams they still tune the hemi for 89, and I can tell you 91 also with be great.

This engine is designed to meet all
emissions regulations and provide
satisfactory fuel economy and
performance when using high-quality
unleaded gasoline ... The use of
89 octane plus gasoline is recommended for
optimum performance and fuel economy

 

[Tulecreeper]

2022 owners manual. It seams they still tune the hemi for 89, and I can tell you 91 also with be great.

This engine is designed to meet all
emissions regulations and provide
satisfactory fuel economy and
performance when using high-quality
unleaded gasoline ... The use of
89 octane plus gasoline is recommended for
optimum performance and fuel economy

My owners manual says 87 octane.

 

[Mb7640]

I tried 91 for a month and a half did not see a difference between 91 and 89.

 

[BenchTest]

As @Burla posted, my readings show 87 is acceptable, but engines are tuned for best performance on 89 or higher (not to exceed 93 octane on factory tune). This doesn't explain the sudden onset of hesitation (use of 87 octane). @KeithP do you typically fuel from the same location? 87 shouldn't cause this. Also, ethanol content of what you're using may be in question as well. Please advise.

 

[BenchTest]

I tried 91 for a month and a half did not see a difference between 91 and 89.

This statement tracks. If an engine is tuned for 89 and no mods have been made, 91 would be negligible unless humidity or altitude became a factor.

 

[Curmudgeon]

I've been using 89 octane Top Tier gas, but the place I frequent offer 93 octane for just a couple dollars more per 1/2 tank fill.

I think I'll switch to the 93 for the next 6 months or so, see how the old girl likes "filet mignon" over "ribeye"

 

[Burla]

My owners manual says 87 octane.

that was copy and pasted from 2022 owners manual...

 

[Travelin Ram]

Low octane might contribute to preignition, but there’s no reason to associate that with hesitation.

And assuming it’s the same brand, very unlikely to be any difference between 87 / 89 in fuel additives impacting injector cleaning.

I’m sure the OP has accurately described his experience; but is it coincidence or cause and effect.

 

[KeithP]

As @Burla posted, my readings show 87 is acceptable, but engines are tuned for best performance on 89 or higher (not to exceed 93 octane on factory tune). This doesn't explain the sudden onset of hesitation (use of 87 octane). @KeithP do you typically fuel from the same location? 87 shouldn't cause this. Also, ethanol content of what you're using may be in question as well. Please advise.

I do not necessarily use the same station or brand of gas from one fill to the next. I purposely switched up when the hesitation was happening thinking it may be bad gas from a particular vendor. Nothing changed until I started using 89.

 

[Docwagon1776]

My owners manual says 87 octane.

6.4L 2500 vs 5.7L 1500. The 1500, which the OP has, always calls for 89.

 

[corneileous]

My owners manual says 87 octane.

What motor do you have? If you have the 5.7 hemi, it actually recommends 89 but says 87 is just OK to use instead.

 

[corneileous]

I’m on my second Hemi half-ton and I’ve always just ran 89 in them. Of course, I’ve never done anything loaded or pulling a trailer with 87 in the tank but at least when the truck for the most part was empty, I really couldn’t tell the difference using 87 but then again, all the times I’ve ever used 87, it was the 100% gas and wasn’t that crap that had ethanol mixed in with it.

 

[PJ Snyder]

I have a 2004 Ram 1500 and have used 89 octane since new. Never had any fuel issues.

 

[Mark47ak]

2022 5.7: at 18k miles I started experiencing a slight hesitation when accelerating from a dead stop. Didn’t matter if the start/stop feature was on or off. This is my 3rd 5.7 and have always just used 87 octane. Both of the other trucks are still in the family. 17 with my son, 19 with my daughter. I know they both still burn 87 octane with no issues. Dealer tried to tell me it may a transmission shift delay. That didn’t make sense to me. Decided it may be a dirty injector issue so…. simple solutions first. I started burning 89 octane. The hesitation went away about half way through the first tank. Still burning it, running about 50/50 city vs freeway driving and averaging 16 mpg (calculated the old fashioned way). Think I’ll stick with the 89 from now on.

Try nonetheless gas, you will see difference. More btu burn equal more power.

 

[Dean2]

I doubt the Octane is the major differentiation, unless it goes back to hesitating as soon as you put 87 back in the tank. Most likely the 89 is better at cleaning. 87 with injector cleaner every 20 Klms works well in the Jeep. I have tried 91 and 87 in the Jeep 5.7 and in my 2500 6.4, and there is no difference in gas mileage. No point in paying 80 cents a gallon more if the mileage is exactly the same.

 

[Laps]

2017 Ram Rebel, using 87 octane for years, with occasional fuel injector cleaner, trouble free, runs fine.