87 octane vs 93 octane - ECOBOOST

[Chili]

There is a good and long thread about this on the 5.0 page but it seems more than a few of the comments pertain to the Ecoboosts (both 2.7 and 3.5). Seemed to make sense there is a thread for the two Ecoboost engines as they are obviously very different than the 5.0.

I've only run 87 octane in my 3.5, or 88 octane e15. 88 e15 should perform like 89 octane for the simple reason, you need a higher quantity of fuel with e15 and that fuel has a cooling effect in the cylinders.

With 88 e15 I have done a best of 13.6 @ 100 in my stock XLT Crew cab 4x4. 3.31 gears, 18" wheels with oem tires. It was cold when I did this and have noticed on cold days I max out around 16-17psi and it runs more boost on hotter days, trying to keep the performance similar.

Anyone have some info to share on octane, stock dyno graph comparisons, or Dragy numbers?

With all the 2024 Mustang GT info dropping I've got performance fever right now. Dream garage would be to add a GT to the stable, but I'm not a two car note kind of guy!

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[bcb97]

I'm not sure if they still do, but Five Star on their website used to have a dyno showing the difference between 87 octane stock tune and a 93 octane stock tune. It was surprisingly noticeable and I believe around 20-30 hp/tq difference if just looking at the graph. It might be for the previous gen ecoboost but should be comparable.

 

[jetfixr1]

With my JB running an E30 blend, my 1 foot rollout 0-60 is 4.73 seconds. 4.97 seconds without the one foot rollout. My truck is a 21 RWD screw 3.55 gear ratio and only a CAI.

 

[Chili]

With my JB running an E30 blend, my 1 foot rollout 0-60 is 4.73 seconds. 4.97 seconds without the one foot rollout. My truck is a 21 RWD screw 3.55 gear ratio and only a CAI.

Wow, that's impressive! What wheel / tire do you have? Edit: I see you have the 20s/33s. Our overall gear ratio should be the same with my 32s. I'm thinking I'm going to give premium fuel a try hear shortly. Sounds like the changes come in the 2nd tank.

I want a tune but I only have 6500 miles on my truck.

 

[jetfixr1]

Wow, that's impressive! What wheel / tire do you have? Edit: I see you have the 20s/33s. Our overall gear ratio should be the same with my 32s. I'm thinking I'm going to give premium fuel a try hear shortly. Sounds like the changes come in the 2nd tank.

I want a tune but I only have 6500 miles on my truck.

I have the stock wheels for my XLT. The JB4 tune could be removed easily should any dealership visits arise. The tune is conservative and Burger Motorsports (JB4) support is great IMO. Honestly if you dont want to do the E85 tune, you can do the 93 which is impressive in itself.

 

[Gros Ventre]

There has been much interplay over whether octane adds power or not. Simply put otane does not enter into any element or formula for how much power is produced. Where octane plays in power productin is what is the design compressin ratio and what octane is needed to prevent detonation. Attached are some diagrams illustrating this. So what is the design point of these engines and how does Gasoline Direct Injection affect that? Note that in the formulae cited octane is not present. So what is Ford's design point? Be nice to know. For now I think they likely derated the engine so they could advertise 87 octane... while giving the engine room for increased power production if higher ocane is used.

 

[fordtruckman2003]

For now I think they likely derated the engine so they could advertise 87 octane... while giving the engine room for increased power production if higher ocane is used.

So now you admit the engine can produce more power on higher octane?

 

[Cheez_Greater]

https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

This article shows 20 rear wheel hp and about 2 PSI boost increase with 93 octane vs 87 on a 2018 3.5 Ecoboost. I use premium when I plan on towing across mountain passes and 87 all the other time.

 

[Gros Ventre]

So now you admit the engine can produce more power on higher octane?

You misread my post. Try again.

 

[Chili]

https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

This article shows 20 rear wheel hp and about 2 PSI boost increase with 93 octane vs 87 on a 2018 3.5 Ecoboost. I use premium when I plan on towing across mountain passes and 87 all the other time.

I'm cheap so I understand. Some places around here have 88 e15 which is like midgrade, but for 20 cents less than 87.

 

[Gros Ventre]

I'm cheap so I understand. Some places around here have 88 e15 which is like midgrade, but for 20 cents less than 87.

You might do some homework on E15/88 Octane. I bought a load awhile ago and then looked it up. There are some drawbacks like a propensity to separate in your tank. I decided not to use it again...

 

[Gros Ventre]

After that somewhat snippy post above, I went back and did some more homework. Here's a link to an extensive discussion. Bottom line: your recommended octane is good enough as is. Does higher octane help produce design power, maybe, but it depends. Does higher octane produce more power: No. So why does an engine run better on a higher octane? Well a lot of things, for example cylinder carbon buildup which changes compression ratio or high ambient temperatures or pressures. Do dyno tests show things: No. Without controlling for all of the various things that can affect power production dyno tests are nice to know but don't provide any conclusive information. This link is a bit lengthy, but worth a read. Bottom line the owners manual governs and the Ford engineers said 87 is good enough across all operating situations and there is no increase in power for higher octane than specified. Give it a read.

 

[fordtruckman2003]

Manual says for all motors 91 octane for best performance.

 

[WhiteLightningnshitshadow]

So now you admit the engine can produce more power on higher octane?

heeeeeere we go

 

[WhiteLightningnshitshadow]

I'm cheap so I understand. Some places around here have 88 e15 which is like midgrade, but for 20 cents less than 87.

I've actually never heard of that? Is it the cheapest gas you can get? I feel kinda slighted in Colorado. The dealer stated it can take regular, but I've come to find the 85 in Colorado/wy/NM aren't recommended. 85 is 3.45 a gal while 91 (max we can really get) is 3.99. Multiply that by 36gals. I couldn't care less how much power the engine has past like 270 or so HP, but reliability and efficiency are important.

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