93 Octane! I like it!

[javelina]

Even though it can be a waste of money at worst, any harm to the engine or performance if you fill the 3.6L with 89 or 91? I now have two Wranglers in the household - a 2.0L (which definitely gets 91) and a 3.6L for which I am thinking 89 (Silver/Mid grade) may be the best choice?

no harm, except to the wallet....

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[Punkindave]

Has anyone put a boost gage on their 2.0? My WRX would limit boost if lower octane fuel was used. Accidentally put 87 in and couldn't get boost over 8#. Plus fuel got you 15# and 93 got it up to 18#.

 

[Jo's Jeep]

Placebo effect. Followed by a double shot of confirmation bias.

 

[cosine]

at 3.79 - 3.91 / gal for octane 93. i'll stick with the 2.61 / gal for octane 87. so far i'm getting 18 mpg and still in the break in period. thtas with the 3.6

 

[BXFXJeep]

Don't know about the JLU, but when I'm in the US I would put premium in my 15 JKU, definitely drove smoother and MT gears shifted better, these were usually a Toronto to NYC or Syracuse run, but with the price of gas in Toronto, premium is for ultra luxury, maybe if I lived in the US I would use premium more often.

 

[roaniecowpony]

If you think about it, the 3.6L is 220 c.i. (for us old timers) and makes 295 h.p.. That's 1.34 h.p./c.i...... and anyone that knows the historical development of engines knows that's a lot of power for a naturally aspirated engine designed for a common grocery getter. Sure, there are plenty of other vehicles making higher specific power, but dang, 1.34 hp/c.i. on 87 octane is nothing to sneeze at. Quite an accomplishment in my book. I'm thinking we're in the best days so far of the internal combustion engine, even with all the emission requirements. Many backyard hot rodders may disagree with that statement, but I'll stand by it. You go back 50 years to a small block chevy and they had to run 100 octane and to get over the 1hp/c.i. barrier.

 

[crazychile]

Nowhere in this thread has anyone specified if the gas they're using is part ethanol or non-eth. If you compare 93 octane non-eth to 87 with 10% eth, yeah the 93 will give you better mileage, But it's not from the octane rating.

In some states you don't have a choice, but if you do, try the 87 without ethanol. You'll see some slight mpg gains. You'll have to determine if the cost difference vs. mileage gains are worth it, but just something to throw out there.

BTW, in both the JK and JLU, we run 87 octane non-eth. I tried the 93 octane a couple of times and didn't notice any difference. Also consider that depending on where you buy your gas, the high octane stuff might be sitting in the stations fill tank a lot longer, and may not be as fresh.

 

[four low]

Because that's Canadian fuel, eh?

89 Octane here in Central New York, is readily available. At Stewart's gas stations,it's a blend of 87 with Ethanol, and 91, Non ethanol. This blending is at the pump, as there are only 2 in ground tanks, one for 87, one for non ethanol 91.

 

[Johnbuz]

For those of you who think 93 is no improvement over 87 for the 3.6 in preventing knock "pinging" during light acceleration around 1700-2000 rpm's, there is a whole thread dedicated to it. I agree that it makes a difference but is not a cure-all. https://www.jlwranglerforums.com/forum/threads/predetonation-spark-knock.12267/page-3

 

[Johnbuz]

Heres another thread.
https://www.jlwranglerforums.com/fo...on-jlu-3-6-engine-pre-detonation.10322/page-6

 

[PavementWarrior]

the 3.6 also known as "ole pingy" pings in summer on 87 in CA (I think hippies put something in it in summer). It pings less, still sounds like its gonna fall out on start up sometimes, but hey its a Fiat thing.

I am willing to bet Ole pingy would love 91

 

[PizzaFreak]

To this day I still only use 93. I am averaging almost 24mpg/gallon, and power is off the charts. I experience no knocking ever. You get what you pay for! Nothing will convince me that 93 isn’t the best fuel for a Jeep 3.6. We shall see as the miles add up!

 

[8flat]

91 sure has made my 3.6 run better down low. Also up high towards redline. Which makes sense considering it's such a high compression engine.

I'd love to get my jeep on a dyno to prove it out.

 

[word302]

To this day I still only use 93. I am averaging almost 24mpg/gallon, and power is off the charts. I experience no knocking ever. You get what you pay for! Nothing will convince me that 93 isn’t the best fuel for a Jeep 3.6. We shall see as the miles add up!

Lol

 

[entropy]

I dont think I have more power with 93.
It just feels smoother and the rattle hiccup quick cough on acceleration is gone.

Now... my brakes are squeaking with only 6000 miles on them so thats a different story.

Placebo effect

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