3.6 engine and 87 octane a no-no

[AlgUSF]

I wanted to chime in here. My Jeep seems much more picky about gasoline than every vehicle I've had since my Chevy S-10. I remember when I bought my S-10 in 1995 they sent out a supplement saying to use 89+ octane fuel for a N/A 4.3L V-6. It ran amazing on Amoco Ultimate (remember the gimmick with the see through gas nozzle with the little ball in it). Ever since I got rid that truck I've always used 87 from any pump available.

On my Jeep, I've been noticing pinging at low RPMs so I've started only using Top Tier gasoline (i.e. Shell) at 87 octane. The pinging at low RPMs seems to have gone away. Unfortunately there are no top tier gasoline stations near me, so I have to make sure to get gas when I'm out running errands. I figure when I do trail rides that I may try 89 octane fuel.

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[PyrPatriot]

So why does the user manual state higher octane offers no benefit

 

[NBB]

Higher compression = lower emissions. It's required vehicles meet standards on regular gas because the epa knows that's what people are going to use. Anti-knock sensors and logic are imperfect. It's also not in the manufacturer's best interest that the engine last beyond 100k miles.

Therefore, IMO, it's not engineering or science to cite the owner's manual recommendation as some authority on whether octane is a benefit or not.

Seems like it's helpful - from the sum of experiences posted here - and that makes perfect sense to me with the higher compression engine.

 

[OldGuyNewJeep]

So why does the user manual state higher octane offers no benefit

Because it doesn’t consider anal retentive guys who can’t stand the sound of a little pinging.

87 is all that’s needed.

“I had to replace my engine, today, because I was too cheap to buy Amsoil and 93 octane!”, said no one ever.

 

[TxJeepers]

On my 4th Wrangler with a Pentastar 3.6 and all have performed well on 87 octane for me.

 

[AlgUSF]

"Gasoline" isn't what it used to be with all of the different regional formulations. I go to Michigan on vacation every year or so, and there is something about "Michigan Gasoline" that performs amazing. My gas mileage goes up 8-10pct from the fuel that I grab in Kentucky and take across the flat state of Ohio.

 

[zgrw]

Owner's manual says, for 3.6, higher octane provides no benefits. It is a different story for 2.0 though. 2021 Owner's manual page #432

 

[AlamedaJeep]

Because it doesn’t consider anal retentive guys who can’t stand the sound of a little pinging.

I guess this is me . I used 87 for the first two years and then tried 91 and the pinging went away. The pinging wasn’t bad, but it did bug me, and so far I’ve stuck with the higher octane.

 

[PyrPatriot]

can anyone provide audio of what pinging sounds like

 

[aeonixx1001]

I don't feed my dog shitty dog food, I certainly won't serve my Jeep anything but the best +91 minimum. It may be Psychological (according to the observation of the statement above) but I swear it runs better, gets better mileage, and has much better pick up. So I guess that says it all. +87 Good according to whoever wrote that, but not for me. You have a choice now.

 

[blnewt]

I don't feed my dog shitty dog food, I certainly won't serve my Jeep anything but the best +91 minimum. It may be Psychological (according to the observation of the statement above) but I swear it runs better, gets better mileage, and has much better pick up. So I guess that says it all. +87 Good according to whoever wrote that, but not for me. You have a choice now.

I feed our dogs top shelf foods, luckily our Jeep runs fine on top-tier 87 octane. Like I mentioned earlier, if I can find crapanol-free gas I'm all over it, but unfortunately it's only available on our road trips, not locally

 

[zgrw]

Here is an investigation/test on if higher octane really performs better for an engine optimized for 87;



Long story short, don't waste your money on 91 octane if you have 3.6

 

[blnewt]

can anyone provide audio of what pinging sounds like

Can't provide audio, but if you can imagine a few ping-pong balls shaken inside a pringles can, that might give you a pretty good idea

 

[NBB]

Long story short, don't waste your money on 91 octane if you have 3.6

Good gawd, that is a dumb video. Long story short - don’t waste your time watching a 5 yr old movie that contains zero on a modern high compression engine and emissions, and even less about a 2018+ 3.6 Pentastar. Use your brain, people, not some pop nonsense interviews of gas station employees.

 

[AlgUSF]

I feed our dogs top shelf foods, luckily our Jeep runs fine on top-tier 87 octane. Like I mentioned earlier, if I can find crapanol-free gas I'm all over it, but unfortunately it's only available on our road trips, not locally

I agree! The FCA engineers designed the engine around 87 octane fuel, and running around town in anything higher is wasting your money. The FCA engineers are trying to keep the Jeep alive while keeping to government regulations.

If I'm going to spend all day at low RPMs doing silly stuff off-road in my Jeep with the windows down, it may be worth putting in 93 to lose the annoying pings. It may in-fact have no effect. I'll find out the next day out in the sand.

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