Fuel question

[AZ Hella]

Plenty of threds on this topic for sure. I will say my 3.6 6spd has less low speed knock on 91 opposed to 87. Arizona is not known for high quality fuel.

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[alphawolff]

The jeep requires 87, but running 89 will help prevent knock, especially in hotter climates

 

[Jeep Wick]

I do live in a warmer climate, and premium made a big difference on my manual Jeep. It would ping on lower octane, and this was since new. I was not 'masking' an engine issue, it was overall great for 45k. Premium ran better, fact.
But now I have an auto etorque, I will admit changing octanes is less noticeable. Maybe data logging with a scan tool could show if it matters?

 

[Joe Nichols]

Which is better?

1. 87, no Ethanol
2. 89, 10% Ethanol
3. 92, 10% Ethanol

I only use 87 no E in my 3.6L and the performance has been excellent.

 

[Flip]

Plenty of threds on this topic for sure. I will say my 3.6 6spd has less low speed knock on 91 opposed to 87. Arizona is not known for high quality fuel.

@AlphaWolf

I should have been more specific in my original post. That's what my main concern is, which fuel is healthier for the 3.6, the higher octane or no Ethanol regarding longevity, less engine ping. I'm not having issue but if running one is better than the other, I certainly will use it. The fuel station I regularly use now offers an 87 no Ethanol that's what prompted my question.

You guys have noticed the higher octane seems to do a little better regarding ping yeah? That's good to know.

Thank you

 

[SargeDiesel]

Have ya tried diesel?

@ Every fill up ! Great suggestion ?

 

[Jeffy56]

IMO, based on real world use, observation, tech articles, fuel system problems (not Jeep), reading the manual, working with petroleum products, etc. Consider the following for gas engines. Note: diesel may have "blends", like oxidizers, too. All EPA driven.
1. Ethanol is but one additive to extend gasoline supplies, but mostly as a emissions reducing agent. Unfortunately, it costs gas mileage and power. I seriously doubt it has a net improvement.
2. Major metros/states have winter blends and summer blends design to reduce specific emissions. Where I live in AZ, rural gas has more power and better mileage than city gas. Telltale, it's cheaper too!
3. Ethanol may clean some deposits in fuel systems, but what's more important is using a high detergent fuel. As stated in the manual, and manufacturer recommended since the 2010s. Use a hi-grade "Top Tier" or Techron labeled gasoline.
4. Octane may be recommended for some engines. Point #3 hi-grade gasoline is more important for ALL engines, especially those with direct injection.

 

[west tex]

My '21 Wrangler has the 2.0T engine and I normally run 91 octane in it with good results.

BUT, I'll fill up with nonethanol of any octane rating when it's available. I notice a definite increase in gas mileage and no decrease in performance.

 

[Flip]

As of today 4-6-24, 87 octane no Ethanol $4.07 per gallon, 93 octane 10% Ethanol $4.05 per gallon. 89 octane $3.79 per gallon.

 

[alphawolff]

IMO, based on real world use, observation, tech articles, fuel system problems (not Jeep), reading the manual, working with petroleum products, etc. Consider the following for gas engines. Note: diesel may have "blends", like oxidizers, too. All EPA driven.
1. Ethanol is but one additive to extend gasoline supplies, but mostly as a emissions reducing agent. Unfortunately, it costs gas mileage and power. I seriously doubt it has a net improvement.
2. Major metros/states have winter blends and summer blends design to reduce specific emissions. Where I live in AZ, rural gas has more power and better mileage than city gas. Telltale, it's cheaper too!
3. Ethanol may clean some deposits in fuel systems, but what's more important is using a high detergent fuel. As stated in the manual, and manufacturer recommended since the 2010s. Use a hi-grade "Top Tier" or Techron labeled gasoline.
4. Octane may be recommended for some engines. Point #3 hi-grade gasoline is more important for ALL engines, especially those with direct injection.

Ethanol is actually a power adder. It allows the combustion chamber to run cooler, allowing the engine to advance timing resulting in more power. E85 tunes are very common in the performance community to gain additional power with little to no modifications. The downside is you use ~33% more of it to achieve the same amount of power as normal gasoline, resulting in horrendous MPG.

Premium also isn't really effected by direct injection, it's just that usually direct injection engines usually also run a higher compression level since they're going for max efficiency. That's what allows the premium fuel to really shine.

@AlphaWolf

I should have been more specific in my original post. That's what my main concern is, which fuel is healthier for the 3.6, the higher octane or no Ethanol regarding longevity, less engine ping. I'm not having issue but if running one is better than the other, I certainly will use it. The fuel station I regularly use now offers an 87 no Ethanol that's what prompted my question.

You guys have noticed the higher octane seems to do a little better regarding ping yeah? That's good to know.

Thank you

I'd just run the 89 10% ethanol. Maybe swap to premium if it's hot as hell outside or you expect to be doing some heavy towing. The octane is more important here rather than the ethanol levels. The engine really retards timing pretty commonly on 87. It's totally safe to run 87, but you will miss out on some power in certain situations.

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