3.6 engine and 87 octane a no-no

[Kracka]

4 1/2 year old thread...RISE FROM THE GRAVE!

Our 3 Pentastars have always run a bit smoother on 88 or 89 vs. 87.

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[Laststand]

4 1/2 year old thread...RISE FROM THE GRAVE!

Yep, on every vehicle forum I've ever been on - "debates" on oil, fuel/octane, warranties as Ken points out. Then as you mentioned resurrected every year or so to be rehashed again. Most of it's a waste of time but some of the comments and "thoughts" are entertaining.

 

[gek]

 

[Terrymo]

 

[AFD]

Sure, it's a myth or whatever. Jeep says it's fine (and the 3.6L has knock sensors to retard timing), so I'm sure it's probably fine.

11.3:1 in the JL 3.6L is quite a bit higher than the JK 3.6L at 10.2:1 compression ratio, so I've been running 89 instead of the cheaper 87. Engine feels quite a bit smoother and is noticeably quieter overall. Could be my imagination, but the added expense seems relatively minor compared to most maintenance and repairs (at least around here, which is usually 20 to 50¢ extra). If I could find 88 unleaded, I'd run that instead, but all of our stations jump from 87 to 89 to 91 (up to 93) for some reason.

 

[NPC 20883467]

This may be be a zombie thread, but it gives an opportunity for those of us who've been running premium since the original post was written to check in. I've been running 91 pretty much exclusively since I bought this unit new in '20. Occasionally I have to fill with 87 when 91 is not available, and the difference in performance is stark.

...Engine feels quite a bit smoother and is noticeably quieter overall...

...and gets better mileage.

With a compression ratio of almost 11.5:1, it seems stupid to not run a fuel that makes the most of that. And for those of us living at high altitude, the difference between non-alcohol 91 octane and the 87 minivan gas is really dramatic.

 

[DaltonGang]

Mine loves 93 Octane. But, prolonged use of 87 octane causes the engine to idle slightly rough. 95 percent of my driving is short drives, and I fill up every 10-14 days. So, I dont.mind spoiling the Jeep with mostly 93 octane.

Since posting my comment, in 2020, I have tried all octane ratings. I have even tried Ethanol Free gas in different octanes. For the past 3+ years I have.pretty much exclusively used 87 octane. I will say, the Ethanol Free gas makes my engine run the smoothest, no matter the octane. Also, using quality gas makes a difference. Buying gas from non big named gas companies is a roll of the dice in the quality of gas and additives you get. I stick with Exxon/Mobil or Chevron. The gas from them seems more consistent, and the engine idles smoother, during the high Houston heat of the summers. Just my .02¢.

 

[LukeDagny]

Yep, on every vehicle forum I've ever been on - "debates" on oil, fuel/octane, warranties as Ken points out. Then as you mentioned resurrected every year or so to be rehashed again. Most of it's a waste of time but some of the comments and "thoughts" are entertaining.

What tires are the best? And what pressure should I run?

 

[Laststand]

What tires are the best? And what pressure should I run?

Or which is better the 3.6 or 2.0 to really get things started.

 

[Terrymo]

We could just have one gigantic poll for most of these topics like the census bureau does and then the forum server wouldn’t crash all the time.

I run 91, change the fluids and filters way too often, run an RPM fan controller, and drive with my fingers crossed. Nobody can say I didn’t try if my engine leaves the chat.

i know you can put 37s on a Jeep with no lift so at least that question is covered

 

[Traveller128]

Check out what Livernois says about what's on the table with the 3.6.

It's a high static compression engine, BUT cam phasing can change dynamic compression a lot. There's a LOT of room for better overall tuning improvement.

Non-ethanol does indeed make a difference in fuel mileage, and it's a better fuel for port injection. That's with any engine, not the just Chrysler stuff. That's been thoroughly debated on just about every engineering and automotive forum there is.

 

[jellis4148]

I've ran 91 Ethanol free since day one. That's the only way you can get fuel in Missouri without Ethanol. I also by top tier fuel. The engine runs smooth. Can't really say anything about fuel mileage, it sucks since I do mostly city driving. If I get on the road and drive 60 mph I'll get around 18. I typically average around 12-13.

 

[NPC 20883467]

I've ran 91 Ethanol free since day one...If I get on the road and drive 60 mph I'll get around 18.

Same here, and I can't figure it out. I've got a dump truck that gets better mileage than this.

 

[Traveller128]

We can find 87 non ethanol nearby. I use 91 non-eth in the Supercharged 5.7 Charger. Down South they have 89 non-eth, used to be 90. That's what the guys riding offroad bikes/quads used to use.

87 non-eth is available in more than one place. I notice fuel mileage improvement and smoother operation (not as much surging when accelerating).

When we're out of warranty, we'll be doing the Livernois package and using the 87 tune. The 3800-4800 TQ/HP dip is real and I want that gone.

 

[2nd 392]

We could just have one gigantic poll for most of these topics like the census bureau does and then the forum server wouldn’t crash all the time.

I run 91, change the fluids and filters way too often, run an RPM fan controller, and drive with my fingers crossed. Nobody can say I didn’t try if my engine leaves the chat.

i know you can put 37s on a Jeep with no lift so at least that question is covered

Alas- soon we will have to resurrect oil threads, I haven’t seen one in days, heck weeks— Whose Gonna Fill His Shoes ? Now, what about this controller Thingy ?

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