87 Octane in an EcoBoost with GPF

[710-oil-614]

Makes sense that 93 octane will increase HP over 91 octane.

Ford's official 2025 Maverick technical specifications state; "*Horsepower and torque ratings based on premium fuel per SAE J1349® standard. Your results may vary.*"

Did not specify if “premium” was 93 or 91. But Ford recommends “91 octane or higher” for best performance - so using 93 octane will help not hurt. Whew

If you look up the standard J1349 you'll see that it is specifies 91 octane.

The 2.0 is mapped to 91 octane and there is no additional power realized by using 93 octane unless you take advantage of a tune from Cobb or Panda.

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[Chops]

The 2.0 is mapped to 91 octane and there is no additional power realized by using 93 octane unless you take advantage of a tune from Cobb or Panda.

I was assuming 91 was used in the 250hp estimate…not 93. Thank you for confirming - I trust you more than AI on this matter

Going to stick with 91 even if 93 is available at my pumps. Top Tier Plus will trickle down to all octanes by next year.

 

[sajohnson]

More from the ultimate, unassailable source (Google):

"Yes, your Ford 2.0L EcoBoost will see a performance increase (more horsepower/torque) with 93 octane compared to 91 octane, as Ford tunes these engines to reach their advertised power figures using premium fuel, allowing for more aggressive timing and boost without knocking; while you might not feel a huge difference daily, you'll get closer to the engine's full potential, especially under heavy load, towing, or in hot weather, where 93 provides better knock resistance.

Why Higher Octane Helps:
Knock Resistance: Higher octane fuel is more resistant to premature detonation (engine knock) under the high pressures and temperatures of a turbocharged engine.
Engine Tuning: The engine's computer (ECU) detects the higher octane and adjusts engine timing and boost levels to take advantage of it, producing more power.
The 91 vs. 93 Difference:
Ford's Specs: Factory performance figures (like 250hp) are often based on 91 octane or higher; running 87 octane can reduce output (e.g., to 238hp).
Noticeable Gains: The jump from 91 to 93 is smaller than from 87 to 91, but you'll still get a slight edge in power and responsiveness with 93, as it offers even better knock protection.
When You'll Feel It Most: The benefits are most apparent during hard acceleration, towing, or in hot conditions, where the engine works harder and needs that extra knock resistance.
In Summary:
For daily driving, 91 octane is great and recommended for full potential, but if you want to extract every bit of performance from your 2.0L EcoBoost, 93 octane is the way to go, offering a slight, but real, performance edge over 91."

The above certainly could be true -- if the ECU can take advantage of octane levels above 91 -- but I could not find any consensus. One test of acceleration with and without a trailer showed essentially no difference at all between 91 and 93 octane. See the chart in post #6:

https://www.mavericktruckclub.com/f...e-with-ethanol-edition-by-project-farm.34250/

I'd like to think that Ford gets hp and torque ratings using 91 octane, since that is the max in much of the country, but allows the ECU to take advantage of higher octane levels. 93 is very common in many areas.

All the ECU knows is whether the engine is beginning to knock. It would make sense for it to be able to slowly increase boost and timing advance to the absolute maximum conceivable levels (cool damp day, minimal load, level ground, 94 octane Sunoco gas) -- to make sure nothing is 'left on the table.' It would be a shame to base max boost and ignition advance on a maximum octane level of 91.

 

[Badknee]

And why do you need that extra 10 percent power in an engine already rated at 250 hp?

So I can "chirp" the tires when I hit third gear.
OOPS... I forgot I'm not driving my old friend's 390 Mustang with a Hurst shifter.

 

[Chops]

' It would be a shame to base max boost and ignition advance on a maximum octane level of 91.

It makes sense that Ford mapped the ECU at 91 octane to get 250hp as 710-oil-xxx stated in his post.

Mapping at 91 octane makes it safer to use 87 octane without knocking.

The aftermarket companies who fiddle with the ECU and sell their programs usually frown (prohibit?) upon using 87 octane. Advise using 93 probably.

I’m not going to fiddle with my ECU by paying a third party for increased HP beyond the 250 - although many on the forum are anxiously awaiting companies like Cobb to break the code

 

[Meeka]

So I can "chirp" the tires when I hit third gear.
OOPS... I forgot I'm not driving my old friend's 390 Mustang with a Hurst shifter.

Chirp the tires on a Mav and with all the problems they have with the shafts that are so flimsy to begin with…… go for it.

 

[sajohnson]

It makes sense that Ford mapped the ECU at 91 octane to get 250hp as 710-oil-xxx stated in his post.

Mapping at 91 octane makes it safer to use 87 octane without knocking.

The aftermarket companies who fiddle with the ECU and sell their programs usually frown (prohibit?) upon using 87 octane. Advise using 93 probably.

I’m not going to fiddle with my ECU by paying a third party for increased HP beyond the 250 - although many on the forum are anxiously awaiting companies like Cobb to break the code

I've had my 2002 WRX at Cobb Stage 2 for almost 20 years. There are several tunes -- one for each of the common octane ratings; an "eco" tune; a "valet" mode, etc. They do recommend that customers use the octane the particular tune is set for (or higher).

We have no plans to mess with our Badlands. It's plenty fast enough as-is, running 93 octane.

Still, I'd hope that Ford programmed the ECU such that it can adjust timing and boost over a wide enough range to take advantage of all of the octane ratings typically sold (at least in some areas) -- up to 94 (Sunoco) or at least 93.

If not, oh well. No big loss. Just that people buying 93 octane would be paying more for no additional benefit.

 

[710-oil-614]

More from the ultimate, unassailable source (Google):

"Yes, your Ford 2.0L EcoBoost will see a performance increase (more horsepower/torque) with 93 octane compared to 91 octane, as Ford tunes these engines to reach their advertised power figures using premium fuel, allowing for more aggressive timing and boost without knocking; while you might not feel a huge difference daily, you'll get closer to the engine's full potential, especially under heavy load, towing, or in hot weather, where 93 provides better knock resistance.

Why Higher Octane Helps:
Knock Resistance: Higher octane fuel is more resistant to premature detonation (engine knock) under the high pressures and temperatures of a turbocharged engine.
Engine Tuning: The engine's computer (ECU) detects the higher octane and adjusts engine timing and boost levels to take advantage of it, producing more power.
The 91 vs. 93 Difference:
Ford's Specs: Factory performance figures (like 250hp) are often based on 91 octane or higher; running 87 octane can reduce output (e.g., to 238hp).
Noticeable Gains: The jump from 91 to 93 is smaller than from 87 to 91, but you'll still get a slight edge in power and responsiveness with 93, as it offers even better knock protection.
When You'll Feel It Most: The benefits are most apparent during hard acceleration, towing, or in hot conditions, where the engine works harder and needs that extra knock resistance.
In Summary:
For daily driving, 91 octane is great and recommended for full potential, but if you want to extract every bit of performance from your 2.0L EcoBoost, 93 octane is the way to go, offering a slight, but real, performance edge over 91."

The above certainly could be true -- if the ECU can take advantage of octane levels above 91 -- but I could not find any consensus. One test of acceleration with and without a trailer showed essentially no difference at all between 91 and 93 octane. See the chart in post #6:

https://www.mavericktruckclub.com/f...e-with-ethanol-edition-by-project-farm.34250/

I'd like to think that Ford gets hp and torque ratings using 91 octane, since that is the max in much of the country, but allows the ECU to take advantage of higher octane levels. 93 is very common in many areas.

All the ECU knows is whether the engine is beginning to knock. It would make sense for it to be able to slowly increase boost and timing advance to the absolute maximum conceivable levels (cool damp day, minimal load, level ground, 94 octane Sunoco gas) -- to make sure nothing is 'left on the table.' It would be a shame to base max boost and ignition advance on a maximum octane level of 91.

Please stop posting AI if I wanted to read AI I will.

We know no additional power is gained from using 93 on stock tune.

 

[sajohnson]

Please stop posting AI if I wanted to read AI I will.

We know no additional power is gained from using 93 on stock tune.

In all seriousness, how do we know that?

I've searched several different ways and haven't found anything definitive from a solid source?

Has Ford published anything about it?

 

[710-oil-614]

In all seriousness, how do we know that?

I've searched several different ways and haven't found anything definitive from a solid source?

Has Ford published anything about it?

Yes. Ford has specified they use the SAE standard that the engine is mapped to 91 octane

 

[sajohnson]

Yes. Ford has specified they use the SAE standard that the engine is mapped to 91 octane

Absolutely correct.

My question is, will it make even more hp & torque when burning 93 or 94 octane?

I'm just curious. I hope the answer is yes, but it's not a big deal.

 

[Chops]

Looking at all the evidence presented on this forum, hard scientific facts, and proprietary info not presented - it is the opinion of Chops that:
87 Top Tier = ~238hp
91 Top Tier = ~245hp
93 Top Tier+ =250hp with aftermarket tunes raising it even higher.

Will be interesting to see if the upcoming Ford Performance 300T turbo/intercooler upgrade will include a tune or a recommendation to use 91/93 and avoid 87?

 

[710-oil-614]

Absolutely correct.

My question is, will it make even more hp & torque when burning 93 or 94 octane?

I'm just curious. I hope the answer is yes, but it's not a big deal.

Not without a tune, no.

 

[Chops]

Not without a tune, no.

How does the existing tune keep the higher octane from developing more power?

And how do aftermarket tunes override the OEM tune to develop more power?

I know tunes work - but really don’t know how. Also, Ford is currently blocking the aftermarket folks from accessing the ECU. How is that done?

Appreciate your expertise

 

[BLUEOVALRACER]

In the hot thinner summer air my Ecoboost thrives on 93 octane ethanol FREE. I call it real gas.
I don’t like burning corn.
Increased mpg’s, smoother idle and power I can feel.
In the cold dense winter air 87 octane works just fine. My mpg drop is minimal, say 1 mpg and that’s mostly due to my key fob start warm ups from inside the house.
Ten to fifteen minute warm ups.

I filled up with 90 octane ethanol free fuel Yesterday I usually use 93 octane with 10/15 percent Ethanol. They only had 90 octane ethanol free fuel not 93 octane like You use. I'll let You know if I get better mileage on the ethanol free fuel. The bad part is a have to drive 20 minutes to get it,the stations within 10 minutes of My house don't have ethanol free fuel!!

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