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Discussion Starter · #1 ·
Anyone else notice a increase in pack is a increase in power and/or fuel economy when using 93 is E when using 93 rather than 87 octane? It's hard for me to tell because I start because I started using the 93 the same time that I is the same time that I put in new spark plugs, new oil/ filter, new air filter, and liquid moly ceretec. Also wouldn't a more complete burn help with reduced deposits? Timing should be automatically adjusted So that's not a concern on a modern engine. Any thoughts?
 

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Anyone else notice a increase in pack is a increase in power and/or fuel economy when using 93 is E when using 93 rather than 87 octane? It's hard for me to tell because I start because I started using the 93 the same time that I is the same time that I put in new spark plugs, new oil/ filter, new air filter, and liquid moly ceretec. Also wouldn't a more complete burn help with reduced deposits? Timing should be automatically adjusted So that's not a concern on a modern engine. Any thoughts?
No.
 

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When I can get it I'm using 93 ethanol-free. It makes a profound difference -- definitely more power and better MPG. I doubt it's the octane. I can't quantify the improvement in power since that is rather subjective, but I think the transmission shifts less on the hills -- again, that's subjective, but something I notice. The MPG figures are empirical data and I'm about 3MPG or 10% better fuel economy.

i've not had the opportunity to try ethanol-free regular. It if exists, it's not available anywhere that I go.

I started a thread on this a few days ago: Non-ethanol gasoline. Feel free to chime in.
 

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I'm with Lundy on this one. It's all in your head, and/or self fulfilled by subconsciously driving differently because you are expecting something, or muddied by changing too many things at once, etc.

The owner's manual states that the 2.4 is designed and intended expressly for 87 octane fuel, and it states that there is no benefit from running a higher octane fuel. It does not have programming to take advantage of high octane fuels.

The one part that is real is non-ethanol is a teeny bit better better for MPG, but not better enough (it's higher cost eclipses mpg gain).
 

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Discussion Starter · #5 ·
The same owners manual that says to not change the coolant and plugs until 100k miles, or that the differentals and ptu/transmission never need changing? I'll stick with science on this one not a Jeep owners manual.
 

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I'm with Lundy on this one. It's all in your head, and/or self fulfilled by subconsciously driving differently because you are expecting something, or muddied by changing too many things at once, etc.

The owner's manual states that the 2.4 is designed and intended expressly for 87 octane fuel, and it states that there is no benefit from running a higher octane fuel. It does not have programming to take advantage of high octane fuels.

The one part that is real is non-ethanol is a teeny bit better better for MPG, but not better enough (it's higher cost eclipses mpg gain).
Placebo effect is real. People pour a pint of fuel system cleaner into their gas tank, take it for a drive and think they have more power. Silly. It takes the whole tank to make a difference so any improvement would be gradual, not instant.

As for octane, I agree. However, the price difference in ethanol-free is about 10% -- about the same improvement in MPG, so while I agree it's a wash, I'd just as soon use the better fuel for what amounts to even money.

@UsmcCompass my plugs are at 60,000 and performing just fine. The plugs in most vehicles these days are 100,000 mile plugs (not so on the 1st gen Compass), regardless of make. I tend to change my other fluids at 3-year intervals which for me is a little shy of 100,000 miles. Neither time nor miles are friends of our fluids.
 

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Discussion Starter · #7 · (Edited)
My plugs were destroyed at 30k. The manual says 10 years or a 100K for the coolant. And I believe transmission says it never needs to be changed. Quite the advice. In terms of octane I believe 93 has more of a complete burn which reduces engine deposits which in turn increases the potential life of the engine. As for saying this engine cannot adjust timing for knock or efficiency is just ridiculous.
 

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Octane has no effect on "complete burn." You'd damage the cat if it didn't all burn. Octane is only to prevent detonation knock, and engine management will automatically retard the timing if you run into that. The engine is made for 87 octane (US rating), higher is a waste of money.

Spark plugs are 100K, per the owner's manual, which is typical for iridium tipped ones. I have no problem running an organic acid antifreeze for the recommended 150K, it's not the old school green stuff. This isn't the 1950's, 3K oil changes are also a thing of the past.
 
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