87 vs 89 octane

[DGreenJets]

What is everyone using for gas? If anyone is/has used premium have you noticed any diferences?
Thanks!

 

[CAMDENN]

What is everyone using for gas? If anyone is/has used premium have you noticed any diferences?
Thanks!

I only use 93 from Exxon and yes, my engine runs very smooth. Also, I pour a 32 oz bottle of Techron into the tank every other month.

 

[Lobo-Tremor]

93 from Valero. It's the only 93 for sale that I have found here in Mexico.
That's what the JB4 tune I have calls for.
And yes, I can tell the difference.

 

[DoubleT]

When I first got the truck, I ran 87 but it didn't feel great. Sluggish at times, rough shifting. Changed over to 89 and it smoothed out significantly. Never have run 93 or felt the need, which I am very thankful for considering the current prices. 89 is bad enough.

 

[Iconic5.0]

I watch Flying Wrenches a lot. He says the newer 5.0 and EB will run smoother and more responsive on 93. So for the first time I am giving it a try to see.

I think it runs fine on 87 but I know if you are working the engine towing you want the premium for high compression engines. Hard to justify the cost of 93 if you are just daily driving.

 

[Rabidtastic]

I get a little better mpg in my EB on 93 and the butt dyno says a little extra power

 

[ErlichBachman]

I run 87 most of the time from a price perspective (most of my miles are just stop and go DFW highway traffic). But throughout summer and on road trips I run 93 or zero ethanol 90/91 (whichever i can find) because the manual says higher octane is recommended for best performance.

slight MPG improvement at 93 or zero ethanol but at the cost of higher $/gal. does feel better overall with those as well but not enough to run it 100% of the time. sitting at 57k miles with no mechanical concerns.

 

[teamroper60]

When I first got my truck, I ran 87. It ran ok but nothing spectacular. I decided to try the higher octane and the performance difference is very noticeable.

Mileage is up a little but not enough to cover the extra cost. Nonetheless, its 91 or 93 (when available) as I like the better performance, even if my bank account doesnt.

 

[muck7]

been running 93 since I made the purchase , not sure what the difference is

 

[Iconic5.0]

been running 93 since I made the purchase , not sure what the difference is

The higher octane is more stable under heat and compression. Layman terms, less combustible. When using 87 octane in a high compression engine the fuel can pre detonate before the spark, on the piston up stroke which can break stuff. It’s similar to how diesel engines work. As the piston comes up and compresses air, it heats and that heat can set off low octane fuel. Engine management adjusts timing to compensate with lower octane and why the engine may not run as smoothly or down on power. This really plays a big part in forced induction with turbocharged or supercharged engines because the up the compression and add on aggressive driving or towing and the heat gets up there making low octane even more likely to pre detonate. This is why you run premium. It’s no cleaner and has the same detergent additives.

The 5.0 has a 12:1 compression and 3.5EB has 10.5:1 with Turbos

 

[TwistedADV]

What is everyone using for gas? If anyone is/has used premium have you noticed any diferences?
Thanks!

I bought my truck used and the trip meter showed 15.4 mpg for 6300 miles... They filled the truck up with 87 octane and stated the previous owner only used 87. 87 felt fine - it was so much better than my old 2003 King Ranch., I didn't think much of it. Then after doing some reading on tuning and how the turbos like the 93 I reset the trip meter and have been putting in 93 for the past year. I am sitting at 18.7 over all average for over 8,000 miles (city and HW). My truck feels much better on the throttle with the 93. mine is a 2021. My father in law has a 2025 3.5L King Ranch.. It's super sweet but my father in law will only put 87 in it. I had to drive it on an 8 hr trip, it was significantly laggy compared to my truck and I was barely getting it to read 18.2 mpg at strictly Highway mileage cruising about 70mph. My wife drove my truck right behind us and averaged nearly 21mpg... only difference was the gas...

Do what you want, pay what you want, but for me, I am sticking with 93.. not so much for the better mpg... I like that it drives so much more responsive and a little extra kick. And when I finally get the tune for the truck, It's gonna be even better with 93.

 

[Iconic5.0]

FYI the telltale sign you have pre detonation is engine knocking.

 

[Traveler]

been running 93 since I made the purchase , not sure what the difference is

Same with me. But the last time I filled up, I put Shell 87 octane in it. Because 93 is $5/ gallon now. I swear it seemed to run smoother!
Currently, I don’t tow or anything. It’s just a daily driver. But I might continue using regular octane until the prices come back down.

 

[Spamslurpee]

I run 93 on my 2025 5.0L. It's hard to tell the difference over my previous truck as the rear end gearing was massively different. The Tremor feels a lot faster and more powerful than my STX did. But again, they are very different in terms of options.

 

[Bigred700]

I normally run 91 in my truck and it is a "good" balance between 87 and 93. Slightly better fuel economy but compared to 93 its a bit cheaper. It is also hard to find 93 here. Most gas stations only carry up to 91....
Price today; (Per Litre/Gallon)
87 - 1.799/L - 6.81/Gallon
89 - 2.009/L - 7.60/G
91 - 2.109/L - 7.98/G
93/94 - Cant get an accurate price today but it was 2.199/L - 8.32/G

 

[deepblack]

I normally run 91 in my truck and it is a "good" balance between 87 and 93. Slightly better fuel economy but compared to 93 it’s a bit cheaper. It is also hard to find 93 here. Most gas stations only carry up to 91....
Price today; (Per Litre/Gallon)
87 - 1.799/L - 6.81/Gallon
89 - 2.009/L - 7.60/G
91 - 2.109/L - 7.98/G
93/94 - Cant get an accurate price today but it was 2.199/L - 8.32/G

Where do you live? I need to make sure I don’t drive through there

 

[Bigred700]

Where do you live? I need to make sure I don’t drive through there

lol...Ontario Canada. Very expensive here for fuel and we are not remote or anything like that. Diesel is 2.299/L - 8.70/G