Recommended Octane Rating & Why

[DevilDog]

Ford recommends 87. It's in the owner's manual.

I do get a little better gas mileage with 93 so I mix it up. I would stay on 93 but it's over 40 cents more than 87.

Maybe I'm old and stubborn, but it just doesn't seem right running 87 octane in a high performance motor.

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[DCS]

Maybe I'm old and stubborn, but it just doesn't seem right running 87 octane in a high performance motor.

Just asking for information.

 

[DevilDog]

Just asking for information.

I'm not being critical of you. Just seems odd to me that Ford recommends it.

 

[Scurfie]

I'm not being critical of you. Just seems odd to me that Ford recommends it.

I'm guessing that Ford wants to show the EPA that the GT carbon footprint is small.

 

[Zig]

I'm not being critical of you. Just seems odd to me that Ford recommends it.

Shows how good they’ve gotten by incorporating computer control

 

[RiksDH]

93 BP on both of my babies..!
23 Escalade ESV Sport
24 Dark Horse.
Being a Limo guy and driving all day, 93 on my Caddy just squeezes the max out of it. No benefit obviously in stop and go, but highway I’ve squeezed 26 on this monster. Whatever was i to save on 87, i would definitely loose it on MPG.
No measurements Yet on my DH, (only 500 miles on it) but Will always stick to 93.

 

[Dxm]

I drove NY -> TX and back, so I had time to experiment with different things.

So here's the conclusion after various experiments. The new Mustang gets the best mileage when running Regular gas -- 376 miles for a full tank. Meanwhile Super got me around 330 miles for a full tank. The type of driving I did was just get on the highway and go at around 80 miles per hour the whole way. Here you go:

 

[RLE55]

TopTier 93 for ours and COSTCO has some of the lowest gas prices around.

 

[DCS]

I drove NY -> TX and back, so I had time to experiment with different things.

So here's the conclusion after various experiments. The new Mustang gets the best mileage when running Regular gas -- 376 miles for a full tank. Meanwhile Super got me around 330 miles for a full tank. The type of driving I did was just get on the highway and go at around 80 miles per hour the whole way. Here you go:

According to this YouTuber's testing, there was less pre-ignition (Knock) with 93 Octane.

 

[Dxm]

According to this YouTuber's testing, there was less pre-ignition (Knock) with 93 Octane.

I understand. But in my testing the MPG was significantly better with regular (not premium) gasoline. Granted, this was highway driving exclusively in "Normal" mode: just set the speed for 80 MPH and go for hours on end. Maybe in drag strip performance would have shown the opposite correlation, who knows?

Type of tests I did:

1. filled up with premium 2 times -- got 333 estimation afterwards when filling up at empty
2. filled up with regular 3 times -- got 360-ish estimation when filling up at empty
3. back to premium, filled up 3 times... down to ~ 310 estimate
4.after that, back to regular gas filled up twice, and the MPG estimate improved again, now estimating at 376 per full tank. This is about 27 MPG, which is pretty incredible.


Regarding the "knock", I only heard it at idle speeds and with premium gasoline. Maybe the famous Coyote "knock" / "tick" finally manifested itself. I cannot be sure yet.

In my old '07, I had mostly used regular gasoline and never had any issues. Every once in a while I had filled up with premium, and "maybe" saw some marginal improvements. I was always told that V8s are very forgiving of the fuel you put in them... just sounds like a tractor anyway.

 

[DCS]

I understand. But in my testing the MPG was significantly better with regular (not premium) gasoline. Granted, this was highway driving exclusively in "Normal" mode: just set the speed for 80 MPH and go for hours on end. Maybe in drag strip performance would have shown the opposite correlation, who knows?

Type of tests I did:

1. filled up with premium 2 times -- got 333 estimation afterwards when filling up at empty
2. filled up with regular 3 times -- got 360-ish estimation when filling up at empty
3. back to premium, filled up 3 times... down to ~ 310 estimate
4.after that, back to regular gas filled up twice, and the MPG estimate improved again, now estimating at 376 per full tank. This is about 27 MPG, which is pretty incredible.


Regarding the "knock", I only heard it at idle speeds and with premium gasoline. Maybe the famous Coyote "knock" / "tick" finally manifested itself. I cannot be sure yet.

In my old '07, I had mostly used regular gasoline and never had any issues. Every once in a while I had filled up with premium, and "maybe" saw some marginal improvements. I was always told that V8s are very forgiving of the fuel you put in them... just sounds like a tractor anyway.

I understand what you are saying. You were measuring mileage, while the video is measuring pre-ignition and HP increase.
BTW: The "Knock" he recorded was not the infamous "BBQ Tick".

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