6.4l- 87 vs 89 vs 93

SwollenMonkey16 · Jan 3, 2017

What octane fuel are you running in your 6.4

MADDOG · Jan 3, 2017

92. Getting a bit better mileage, engine runs much better, now tuned for 92 by HF.

Dmopar74 · Jan 3, 2017

I run 89 in my stock 6.4

RAM_Designs · Jan 3, 2017

I run 89 all the time.

BlkZrx · Jan 3, 2017

Mine runs fine on 87, just don't see much difference on the higher priced stuff. A 5% increase in mileage for 10% fuel cost increase makes no economic sense to me..

tjfdesmo · Jan 3, 2017

Stock truck, and I run 87. I tried a couple tanks of 89 and saw zero benefit.

UrbanKnight · Jan 3, 2017

generally, unless you are tuned for a specific octane, there will be no difference that anyone will notice...

RAM_Designs · Jan 3, 2017

Doesn't a higher octane gas burn cleaner?

UrbanKnight · Jan 3, 2017

RAM_Designs said:
Doesn't a higher octane gas burn cleaner?

No..
Mythbusting Octane, The Truth About Gasoline

monteholic · Jan 3, 2017

87 here

tried 89 for a few tanks with no difference at all

Andrew09HEMI · Jan 3, 2017

I ran 87 first cause that's what the dealer put I then I filled with 93 and there's a noticeable difference. Not night and day but if you're paying attention to idle, mds activation and slight throttle response it's definitely there.

Hootbro · Jan 3, 2017

Been discussed many times.

Cliff Notes is the engine adjusts when running either 87 or 89 octane. For commuting and general use, 87 is fine and the math is not there to run 89 octane for any MPG gains.

Only time 89 shines is during heavy hauling or trailer use. Even then, butt dyno using 87 octane will never know the difference.

River19 · Jan 3, 2017

I put so few miles on this rig and when I do it is 70% with a trailer or load that I just rock the 89......truck sees only about 7500 miles per year currently so the $ difference is laughable.

Tundra has done fine for 230K miles on 87, Our Lexus gets ~91 as I mix it up and our Rav is always 87........never saw much use for true premium fuel in modern untuned vehicles......

As others have said, if you plan on tuning it then by all means get a fuel specific tune like MD and his 92 tune etc.

smurfs_of_war · Jan 3, 2017

Began with 87. Switched to 89 for 6 tanks to see if I noticed any measurable benefits. None found, switched back. I am not in the habit of literally burning money.

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drittal · Jan 3, 2017

My favorite gas station used to have 89 for the same price as 87 and it actually had less ethanol than the 87! Their pumps blend 91 with 87 and their 91 is ethanol free. So I always ran their 89. If I was towing I got at least 89.

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nukegm · Jan 3, 2017

mid grade. in colorado its 87. tried premium didnt notice anything....happy new year comrades!

reloaderguy · Jan 3, 2017

I bought a tank of 91 ethanol free and saw an immediate 1.5mpg improvement on the highway. It was $1.20/gal more than cheap 87 so I bought exactly one tank.

SwollenMonkey16 · Jan 3, 2017

Thanks for the feedback fellas. It's almost time for me to fill her up for the first time so just wanted to see what you guys have done since you already have the beast

RAM_Designs · Jan 3, 2017

Wish I could find some ethanol free 87

SouthTexan · Jan 4, 2017

Unloaded, I say run what ever octane you think your truck runs better on and you are comfortable paying for. It's your money do with as you please even if there might not be that much of a benefit. Towing 5k or more especially on a hot day, I say run 89 at a minimum.

I know my old F150 Ecoboost changed timing when 91 octane was added and upped the power to 15 more hp and another 10 lb-ft per Ford. Not sure how much power it adds to the 6.4L(if any), but at the very least it will deter it from knocking or pre-igniting when pushed hard which will keep the ECM from pulling timing and lowering power output.

6.4l- 87 vs 89 vs 93

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