EcoBoosts, Fuel, Octane, Ethanol and Tuning...

[LokiWolf]

So, I am creating this thread as an education thread, and to attempt to get these discussions out of other threads...

This thread IS NOT for the following things:

1. Discussing the merits of the Turbocharged V6 vs NA V8 in the Expedition.
2. Discussing the politics of Ethanol and EPA Numbers.

This thread IS for:

1. Discussing Octane and how the EcoBoosts respond to it.
2. Discussing Ethanol and how the EcoBoosts respond to it.
3. Discussing Tuning options and Experiences.

The reason for combining those 3 things in one thread, is because they are intertwined.

 

[LokiWolf]

I am going to make a few general statements, and I am sure there will be some that disagree.

Fuel Octane:

• 91+ Octane is recommended in EcoBoosts, and needed to to reach factory power numbers.
• 91+ Octane will give you better MPG's.
• 87 Octane will run fine with less power and slightly less MPG's.

Fuel Ethanol Content:

• Ford Manual says E15 is the max that should be run.
• Ethanol WILL NOT damage the fuel system(Even at higher than E15).
• Max Ethanol content you should run on stock tuning is E20.(Ford allows buffer because a station labeled as E15 might not be mixed well).
• Max Ethanol that can be run with tuning on the Stock Pump is E50.
• Higher Ethanol content typically means lower MPG.

General Assumptions that are accurate:

• Greater the Octane(Within Reason) on stock tuning the greater the power. Above 93 the gains drastically decrease.
• Greater the Octane(Within Reason) on stock tuning the better the MPG. Above 93 you will see little to no difference.
• Greater the Ethanol the less the MPG.
• Greatest Power Levels on Stock tuning, within parameters of the Manual, are attained with E15 Treated 93 Octane Premium.
• Greatest MPG's on Stock tuning, within parameters of the Manual are attained on 93 Premium Octane with E0.

I am playing with various Tuners and fuels on the 2020 currently and will post those results when I have them.

So far I have Tested HyperTech(87 & 93), LMS(93 & Maybe E30) currently, and ZFG Racing(93 and E50) is coming.

 

[lam396]

In terms of mpg only, is it possible to know at what price differential it makes sense to go up from 87 octane?

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[LokiWolf]

In terms of mpg only, is it possible to know at what price differential it makes sense to go up from 87 octane?

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I haven’t tested my 2020, but when I tested the 2017 it was about 35 cents that would have been the break even. I run 93 regardless, cause I enjoy the power difference, so does the wife.

You would have to run a few 87 tanks and hand calculate, then run a few 93 and hand calculate.


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[JasonH]

In terms of mpg only, is it possible to know at what price differential it makes sense to go up from 87 octane?

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You'll never make up the price differential with the mpg improvement. Supposedly an 87 tune will perform like the stock tune on premium. I cannot confirm as I have a warranty and am unwilling to risk it.

 

[LokiWolf]

You'll never make up the price differential with the mpg improvement. Supposedly an 87 tune will perform like the stock tune on premium. I cannot confirm as I have a warranty and am unwilling to risk it.

My 0-60 on an 87 Hypertech tune was 1 tenth faster than stock 93...I attribute that more to shifting and less throttle delay than to power...so without a Dyno, I would agree it is probably close.

As far as the MPG increase...at one point my local station was only 30c different, and it was worth it solely based on MPG. Now that it is averaging 45c different, not the case.

But going through the motions and testing 2 tanks of each will tell you if it is worth it to you.

 

[JasonH]

My 0-60 on an 87 Hypertech tune was 1 tenth faster than stock 93...I attribute that more to shifting and less throttle delay than to power...so without a Dyno, I would agree it is probably close.

As far as the MPG increase...at one point my local station was only 30c different, and it was worth it solely based on MPG. Now that it is averaging 45c different, not the case.

But going through the motions and testing 2 tanks of each will tell you if it is worth it to you.

Need the percent difference, not absolute amount. Costco is 1.65 for 87 and 2.15 for 93 here in Houston. That's 30% difference. No way even half that is being made up by an mpg increase. Best I've seen is around 10%.

 

[LokiWolf]

Need the percent difference, not absolute amount. Costco is 1.65 for 87 and 2.15 for 93 here in Houston. That's 30% difference. No way even half that is being made up by an mpg increase. Best I've seen is around 10%.

Agree 100%!


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[Plati]

Do you have more power / accelerate faster with 91 octane vs 87 octane
AND ALSO (at the same time) get better gas mileage?

In other words does the rates of acceleration have to be the same
in order to get better MPG? Or is it one or the other but not both simultaneously?

Lets say, for the purposes of the question ... to achieve the max acceleration increase
or the max MPG increase

 

[JasonH]

Do you have more power / accelerate faster with 91 octane vs 87 octane
AND ALSO (at the same time) get better gas mileage?

In other words does the rates of acceleration have to be the same
in order to get better MPG? Or is it one or the other but not both simultaneously?

Lets say, for the purposes of the question ... to achieve the max acceleration increase
or the max MPG increase

With the same driving habits, 91 or 93 will provide better performance and acceleration compared to 87.

 

[LokiWolf]

Do you have more power / accelerate faster with 91 octane vs 87 octane
AND ALSO (at the same time) get better gas mileage?

In other words does the rates of acceleration have to be the same
in order to get better MPG? Or is it one or the other but not both simultaneously?

Lets say, for the purposes of the question ... to achieve the max acceleration increase
or the max MPG increase

@JasonH is dead on above, but I get what you are saying.

With the same driving habits, MPG will increase with higher Octane. It you "use" the power more obviously the MPG will suffer. Your results per volume though are better. What I am saying is it takes less throttle to attain the same acceleration level with higher Octane. Hence why it improves MPG for most people.

 

[Uturn]

So far the discussion has been octane and mileage or power. My take on the benefits of higher octane is engine health. These engines can potentially suffer from low rpm knock. It gets more prevalent with low octane combined with a little oil vapor (hence the requirement for SN+ oil). The question to ask oneself is "is an extra 30 cents+ a gallon worth it a vehicle that costs in excess of $55k?". Frankly, I have my wife run midgrade just as a cheap insurance policy. It works out to $1200 (extended warranty cost?) in 80k miles.

 

[Saltwater Soul]

I have been keeping a mileage log for each tank that includes such things as:

• Price
• Octane (for the fillup and the "average" for the tank)
• Miles
• Hours
• Off road miles (usually loose sand which is really tough on the mpg)
• Tow miles (for each of 3 different sized trailers)
• Average Speed per tank

I don't have enough data points yet to make strong conclusions, but the simple regressions I have run so far indicate that each "point" of octane is worth about .15 mpg when I control for the other variables. I did this real quickly so I may change my conclusion with more data points or a better model.

Average speed for the tank ends up being a proxy for city/highway miles. Slower average speeds mean I was more stop and go. Faster average speed means I was on a freeway. MPG goes up with average speed (to a point).

 

[LokiWolf]

I have been keeping a mileage log for each tank that includes such things as:

• Price
• Octane (for the fillup and the "average" for the tank)
• Miles
• Hours
• Off road miles (usually loose sand which is really tough on the mpg)
• Tow miles (for each of 3 different sized trailers)
• Average Speed per tank

I don't have enough data points yet to make strong conclusions, but the simple regressions I have run so far indicate that each "point" of octane is worth about .15 mpg when I control for the other variables. I did this real quickly so I may change my conclusion with more data points or a better model.

Average speed for the tank ends up being a proxy for city/highway miles. Slower average speeds mean I was more stop and go. Faster average speed means I was on a freeway. MPG goes up with average speed (to a point).

Nice! Data is good!


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[LokiWolf]

So far the discussion has been octane and mileage or power. My take on the benefits of higher octane is engine health. These engines can potentially suffer from low rpm knock. It gets more prevalent with low octane combined with a little oil vapor (hence the requirement for SN+ oil). The question to ask oneself is "is an extra 30 cents+ a gallon worth it a vehicle that costs in excess of $55k?". Frankly, I have my wife run midgrade just as a cheap insurance policy. It works out to $1200 (extended warranty cost?) in 80k miles.

The EB pulls timing and fueling if it senses knocking, but yes, best way to prevent that from being an issue in the first place is to just run Higher Octane.


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[flying68]

I did my first 6000 or so miles on 87 octane and the last 7000 or so on 91 (highest available) and have not seen any difference in daily mpg. My highway mpg varies too much with wind conditions to see any difference yet (first 6000 had a lot of highway trips).

Side note, without keeping a log book this would be impossible because the dang trip computer is off as much as 1.5 mpg and it isn't consistent.

 

[Fozzy]

The EB pulls timing and fueling if it senses knocking, but yes, best way to prevent that from being an issue in the first place is to just run Higher Octane.


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Is there anyway to tell when it’s pulling timing and fuel? That would be great info to track. I have never heard any of my EB’s knock, but that doesn’t mean it’s not de fueling or pulling trimming.


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[LokiWolf]

Is there anyway to tell when it’s pulling timing and fuel? That would be great info to track. I have never heard any of my EB’s knock, but that doesn’t mean it’s not de fueling or pulling trimming.


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Yes! Got any way of logging or tracking PIDs? Like a MX+?


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[Fozzy]

Yes! Got any way of logging or tracking PIDs? Like a MX+?


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I do have a MX+ but have only used it to turn off the honk when left running. Do I need a special app?


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[LokiWolf]

I do have a MX+ but have only used it to turn off the honk when left running. Do I need a special app?


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The OBDLink App. Should have been a code with your MX+ to get advanced PIDs. Then you are looking for Knock Retard. I can find the specific name tomorrow when the wife is home with the Expy.


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