What Octane Gas Are You Going To Put In Your JL?

[word302]

Everyone keeps saying it is a waste to run higher octane fuel if your vehicle runs fine on 87, and that may be true. But this Pentastar 3.6 does not like 87 at all, in spite of what the manual may say.

This thing pings constantly on 87 unless you are in the mood to drive like a red blooded teenager and rev the piss out of the thing shifting above 4000 RPM from light to light.

I was actually really looking forward to running 87 in my Jeep, but very quickly came to realize that it just isn't happy with it. Especially if you live anywhere with a lot of hills and steep grades. The pinging below 2500 RPM is horrible.

You need to buy better gas. If you're trying to climb steep hills below 2500 RPM then you need a better driver.

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[Majestic]

Everyone keeps saying it is a waste to run higher octane fuel if your vehicle runs fine on 87, and that may be true. But this Pentastar 3.6 does not like 87 at all, in spite of what the manual may say.

This thing pings constantly on 87 unless you are in the mood to drive like a red blooded teenager and rev the piss out of the thing shifting above 4000 RPM from light to light.

I was actually really looking forward to running 87 in my Jeep, but very quickly came to realize that it just isn't happy with it. Especially if you live anywhere with a lot of hills and steep grades. The pinging below 2500 RPM is horrible.

This is my fourth vehicle with a Pentastar in it since 2011. Every one of them used 87 with no problems. Something is wrong with your engine.

 

[bwright1818]

At schools as a recreational boat mechanic, we were always taught that 89 and 93 had more detergency that 87. I have always heard the story, "It all comes from the same tank." I don't like throwing money away any more than anyone else, although I DID buy a JL. But I digress. One day, while filling up at a local Mobil station, there was a generically-labeled tanker truck, making a delivery. I walked up and asked him if it did, indeed, come from the same tank. The answer is yes; however, there is an additive added to the tanker, when it is going to deliver a top tier load. That made me feel better.

 

[DKAwildcat]

I use 87 octane and recently took a trip to the Colorado Rockies from Kansas City. I got 24+ mpg driving through the mountains and got only about 21.5 mpg driving across the Kansas plains. I would have guessed the mileage would have been much lower in the mountains. I normally get about 19 mpg driving in city traffic. Engine is 3.6L V6.

 

[SteadyC]

Here in Colorado, they sell 85, 87, and 91. There’s no 89 or 93. Everyday I do 87, when I go through the mountains I do 91. No issues with 87.

 

[jayteal]

I started putting 89 into my JLUR this summer and noticed a little less pinging and knock....as well as about a 7-10% lift in mpg. Granted I spend about $4 more per fill up with buying a slightly higher octane gas but the return = a little better mpg and the engine seems to perform a touch better and that's worth the extra $4 at fill up for me. I've also adjusted the way I drive and shifting (manual trans) at a higher rpm band than I was used to with my TJ and other daily drivers. That helps as well.

 

[COJLGirl]

I have a 2.0L Turbo so I use the recommended 91 octane.

 

[entropy]

The pentastar V6 is designed to run on 87, that's what you should put in it. I remember when I was in mech. engineering school they explained to us how this works, and why it is useless to run higher octane, as it is "burns slower". High octane is required in most "high performance" turbo engines, that's why the turbo 2.0 requires 91.

If you run 91 on your 3.6 V6 technically you will actually decrease the performance of your engine since it is designed for lower octane. But most likely you won't notice anything because the computer will probably compensate for it. Regardless, it is a waste of money.

 

[Jeeporama]

The higher octane stuff is generally to avoid pre ignition (knock). If you have a turbo or supercharger, you usually need higher octane, which is why the 2.0L turbo calls for it. But for a naturally aspirated engine like the 3.6L, it's just a waste of money to put anything beyond 87. Just follow the manufacturer's recommendations and you'll be fine. It's a Wrangler, not a race car.

 

[smithrd65]

3.6 87 octane 2.0 91
Adding 91 octane does nothing for the 3.6

 

[word302]

The higher octane stuff is generally to avoid pre ignition (knock). If you have a turbo or supercharger, you usually need higher octane, which is why the 2.0L turbo calls for it. But for a naturally aspirated engine like the 3.6L, it's just a waste of money to put anything beyond 87. Just follow the manufacturer's recommendations and you'll be fine. It's a Wrangler, not a race car.

While pre ignition can cause knock, it has nothing to do with octane. Detonation (knock) is caused by running a lower grade of fuel.

 

[IronScott]

Why do people continue to say that the 2.0 REQUIRES 91 when FCA specifically says it’s not required? There is so much incorrect information spewed it’s no wonder people get confused.

 

[HealthRebel]

Everyone keeps saying it is a waste to run higher octane fuel if your vehicle runs fine on 87, and that may be true. But this Pentastar 3.6 does not like 87 at all, in spite of what the manual may say.

This thing pings constantly on 87 unless you are in the mood to drive like a red blooded teenager and rev the piss out of the thing shifting above 4000 RPM from light to light.

I was actually really looking forward to running 87 in my Jeep, but very quickly came to realize that it just isn't happy with it. Especially if you live anywhere with a lot of hills and steep grades. The pinging below 2500 RPM is horrible.

I have 1050 miles on mine. Nothing but 87 octane in the tank the whole time. No pinging at all! My last Wrangler was a 2012 with the 3.6 V6. Nothing but 87 was ever used. Never "pinged" the entire time I had it.

Have your engine checked.

 

[HealthRebel]

I have a 2.0L Turbo so I use the recommended 91 octane.

2020 JL manual, page 230...Fuel Requirements:

2.0L Engine: "This engine is designed to meet all emission requirements and provide satisfactory fuel economy and performance when using high quality unleaded 'regular' gasoline having an octane rating of 87. The use of 91 or higher octane 'premium' gasoline will allow these engines to operate to optimal performance. This increase is noticed in hot weather or other heavier load conditions, such as while towing."

91 octane is only recommended for optimal performance. Not sure the cost difference will be worth it.

Not from you, but there was some talk about using 87 octane in the 2.0L engine would void the warranty. Clearly NOT the case.

 

[HealthRebel]

High octane is required in most "high performance" turbo engines, that's why the turbo 2.0 requires 91.

Not required! Just recommended for optimal performance.

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