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

[From0toJ]

“Was” running 87, but given other threads on here around the sound coming from our 3.6’s, will try 91 henceforth.

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[WES IV]

The owner's manual states that 87 octane is all that is required in the 3.6L V6. Besides the cost of putting in 91 octane fuel, are their any downsides to running it? Could there also be pro's such as power gains, cleaner internals, etc.?

I am used to running 91 octane in my Tacoma that I just sold, but would like to save the money if there is no real benefit to running 91 in the JL.

Great question! I'm looking forward to the answers

 

[sprayingmango]

With 11.3 to 1 compression in the 3.6....87 seems like a bad idea. It is crazy that they put that in the owners manual.

 

[1quick1]

Not sure if they finally switched from winter to summer gas but I've slowly been switching from 87 to 85 (doing half tank of 87 and next fill up half tank of 85) but since going full 85 my MPG have gone up to 19.5 mpg and this is 90% city. If this was the turbo I'd run 91 without question but no point on the V6 when it says right in the manual there is no benefit running higher octane. Placebo is a hell a thing.

 

[crystalbackJL]

Pre-Ignition / Detonation is deadly in any engine. Regardless of what any manual states. Read up on it and you'll learn a lot and help yourself in the long run.

 

[word302]

11

With 11.3 to 1 compression in the 3.6....87 seems like a bad idea. It is crazy that they put that in the owners manual.

11.3:1 is not really that high anymore. If you're not getting knock anything higher is a waste of money.

 

[Adventure.AS]

Not sure if they finally switched from winter to summer gas but I've slowly been switching from 87 to 85 (doing half tank of 87 and next fill up half tank of 85) but since going full 85 my MPG have gone up to 19.5 mpg and this is 90% city. If this was the turbo I'd run 91 without question but no point on the V6 when it says right in the manual there is no benefit running higher octane. Placebo is a hell a thing.

E85 is 85% ethanol, not 85 octane. Are you aware that the 2019 manual specifically states "Do Not Use E-85 In Non-Flex Fuel Vehicles" p533?

 

[JP18]

E85 is 85% ethanol, not 85 octane. Are you aware that the 2019 manual specifically states "Do Not Use E-85 In Non-Flex Fuel Vehicles" p533?

85 Octane is available in Colorado because of higher altitude. Do not confuse with E85.

JP18

 

[Litfuse]

My Sthil dealer said they recommend 93 octane in their small engines. Their branded bottle gas/oil mix is 93 octane. When I asked him about it he said that 93 octane gas does NOT have ethanol. I don't know. Does it? The pumps have a sign that simply says "up to 10% ethanol" but doesn't distinguish between the three grades.

93 octane can have ethanol in it, and to be honest, most gas will. Unless marked, most gas stations no longer carry fuel that does not have ethanol in their gas.

 

[smithrd65]

I will use what the manual calls for.

Putting Premium Gas in an Engine That Requires Regular? Stop It Now
Only 18 percent of new cars require premium. The owners of the other 82 percent waste about $2 billion a year using a gas that provides no benefit.

If your engine runs fine on regular, filling it with premium is unlikely to boost acceleration or fuel economy by more than insignificant amounts. No matter what you’ve heard, premium-grade gasoline won’t do more to clean deposits from your fuel injectors or other parts of the fuel system because today’s regular gas contains the same detergent additives.

 

[word302]

E85 is 85% ethanol, not 85 octane. Are you aware that the 2019 manual specifically states "Do Not Use E-85 In Non-Flex Fuel Vehicles" p533?

It's actually anywhere from 50-85%.

 

[Adventure.AS]

It's actually anywhere from 50-85%.

In other words, like Forrest Gump’s chocolate box, “you never know what you’re going to get”.

 

[Crawdad1028]

I just recently filled up with 93 to see if it got rid of the pre-detonation and with it my Jeep sounds a lot better at high load, low rpms. I don't usually like paying what they want for premium but I'll start running it more often for peace of mind. (Even if it's false peace of mind)

 

[anotherWS6]

I see no benefit in running 91 in theV6. Any minor benefit is certainly not worth the cost. However on the Turbo I think it is debatable. I think there is some benefit but unless you are pushing the turbo hard I doubt its noticible and not worth the 60 cent premium. Even Mopar says the lower octane is OK and won't hurt the engine

"Push the turbo hard?". This guy is tarded. Low to medium throttle inputs on a high gear will get you at or near max boost. It's one of the reasons turbo 4's are so popular - lots of torque. Because of boost. So driving like a normal person is pushing hard. Extreme cylinder pressure doesnt have to be realized on a race track.

The lack of real automotive knowledge on this site is the reason I rarely come here. Guess I got spoiled by a couple of sites with actual car people on them.

For what it's worth, my 6 pings all of the time, especially now that it's getting hot out. It doesn't like 87 gas, and I have zero detonation when I run 91. But I'm not paying for it. Let it ping. Of course that means it's also down on power. Still not worth it. Motor sucks no matter what. Screw these no low end torque having modern motors. My stock 68 Suburban 396 is soooooo much more of a pleasure to drive throttle wise.

 

[unsavory]

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.

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