87 Octane

[DrRaphael]

Have you been satisfied with using the recommended 87 octane? Is there any noticeable upside to burning higher octane?

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[Q6543]

Run 93, with 87 your engine will be pulling timing every time you get on it to prevent pre ignition/detonation.

people have done the logs, frankly 93 is barely adequate for this compression level, and that’s where you’ll see the cars even happier on E30.

some owners flat out don’t care and run 87…
Could never be me though.

 

[Ryunker]

Run 93, with 87 your engine will be pulling timing every time you get on it to prevent pre ignition/detonation.

people have done the logs, frankly 93 is barely adequate for this compression level, and that’s where you’ll see the cars even happier on E30.

some owners flat out don’t care and run 87…
Could never be me though.

I am one of those 87 octane users, have no issues, but don't drive it hard at all.

 

[RLE55]

The 2024 Coyote 5.0 is Gen 4, compression ratio same as Gen 3.
https://www.mustang7g.com/forums/threads/recommended-octane-rating-why.159503/post-3248529

 

[smurfslayer]

Run 93, with 87 your engine will be pulling timing every time you get on it to prevent pre ignition/detonation.

people have done the logs, frankly 93 is barely adequate for this compression level, and that’s where you’ll see the cars even happier on E30.

some owners flat out don’t care and run 87…
Could never be me though.

On the Rap it’s something like .3 seconds to 60mph. Modern engine management is a marvel of technology and engineering in that you can run on cr@p gas in Mexico all the way through top tier super unleaded and the vehicle adjusts for you.

As gear heads, we are pretty spoiled.

I am one of those 87 octane users, have no issues, but don't drive it hard at all.

You won’t know if the car likes it more -or less- until you run a few consecutive tanks of fuel through it.

 

[Alan Applegate]

With knowledge of the owner's manual (?), everything that's been posted, written, and viewed on YouTube, I'm almost appalled that this question keeps popping up. Restating the obvious...

The manuals for the Eco-Boost and GT alike, specifically states 91 or higher octane be used!!

Longer Engine life; Due in part to the high chamber pressures, Eco-Boost and GT alike!

Higher power output, which shouldn't need explanation.

Cleaner engine internals as premium fuels regularly have better detergents if nothing else.

This leaves out about a dozen other reasons.

As for recommendation? Yes, the engine will operate using lower octane fuel, but you shouldn't! If you're still in doubt, reread the Owner's Manual!

 

[fishinrich]

87 works for me. Can't comment on the higher octane, never tried it.

 

[rijndael]

The manuals for the Eco-Boost and GT alike, specifically states 91 or higher octane be used!!

https://www.fordservicecontent.com/...ingEnabled=False&userMarket=USA&buildtype=web

Your vehicle operates on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87.

Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. The use of these fuels could result in engine damage that will not be covered by the vehicle Warranty.

For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer.

 

[Alan Applegate]

You live and learn, but my other comments are still valid.

The following is also in the manual:

For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer. See Towing a Trailer (page 271). Do not be concerned if the engine sometimes knocks lightly. However, if the engine knocks heavily while using fuel with the recommended octane rating, contact an authorized dealer to prevent any engine damage. We recommend Top Tier detergent gasolines, where available to help minimize engine deposits and maintain optimal vehicle and engine performance. For additional information, visit www.toptiergas.com.

 

[rijndael]

Yep, I do live and learn too.

I've run ForScan, data logging, looking at the differences between 87 and 93. Specifically looking for things like spark knock.

I made my decision based on my fuel, driving habits, and the data in ForScan.

 

[Alan Applegate]

One more (of mine) thought. I paid $40,130.68 for my Eco-Boost Premium. That's about one half the cost of a Dark Horse, which doesn't matter, as both sums are a lot of money! Like other owners, I take good care of my vehicles, albeit I'm not anal about doing so. Nonetheless, 4,000 mile oil changes, frequent tire rotations and washing are part of the routine. And so is the use of the best octane pump fuel I can buy. Suit yourself.

 

[fishinrich]

I'll remember this next time I'm towing my boat with the Mustang.

 

[rijndael]

This is a good example of what works for one doesn't work for the other, we're not even in the same area. I'm not garaging my car until summer either. My winter daytime highs aren't in the upper 50s or 60s. We're about to get 6-10" of snow and my regular startup temps are in the low 20s. The likelhood I'll use any of my giddy-up is pretty slim for the remainder of this tank and probably the next one. I may choose to run 87 or 89'ish until that situation changes.

 

[Ryunker]

On the Rap it’s something like .3 seconds to 60mph. Modern engine management is a marvel of technology and engineering in that you can run on cr@p gas in Mexico all the way through top tier super unleaded and the vehicle adjusts for you.

As gear heads, we are pretty spoiled.



You won’t know if the car likes it more -or less- until you run a few consecutive tanks of fuel through it.

Been 7,500 miles last summer, no issues. Again I do not drive it "like I stole it", saving that for March in NC, those will be driven differently than my own.

 

[Bikeman315]

For the 1,736,925 time use whatever the heck you want. It’s your car. Base your decision on your personal usage not what the geniuses on the internet have to say.

As shown in post #8, both are acceptable, neither will damage your engine. Now go out and drive your Mustang!

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