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Hi there,

I have a 2019 Ecoboost Mustang and I've only ever run it on 87 octane. Regular gas you get at the pump. The car is stock with no aftermarket tune. If I fill up with 93 octane, do I need a tune in order to get the performance boost? What is the factory tune designed for? Does the car measure octane in the fuel? LOL? What happens if I fill it with 98 octane (Dubai) or 94 octane (Where I live, we don''t have 93. Instead, 91 or 94)?

Someone please explain this mess lol.

Thanks
 

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Octane rating is a measure of how likely gasoline is to knock. Higher values meaning less likely. The car has a knock sensor, and should detect small knocks.

The car keeps track of a parameter/variable called "Learned Octane Ratio" or "Octane Adjust Ratio" (OAR). I believe the default is 0.00 (eg: when you remove the battery and it resets) but this is bound to change with use. You could only see this value with an OBD II scanner or some form of access port. The range of the value is from -1.0 to +1.0, and represents the adjustment in the cars timing.

By using the knock sensor it will slowly adjust this value. If it detects a knock it will increase the value, and if it hasn't seen a knock in a while it will reduce the value. The ideal value is -1.0
 

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If I fill up with 93 octane, do I need a tune in order to get the performance boost?
No

What is the factory tune designed for?
It's designed for the average consumer who doesn't care, but it will adjust to actually allow better performance with better gasoline.

Does the car measure octane in the fuel?
Yes.

LOL?
I don't find it a laughing matter, but you do you.

What happens if I fill it with 98 octane (Dubai) or 94 octane (Where I live, we don''t have 93. Instead, 91 or 94)?
Octane is just measured differently in different parts of the world. 98 octane in Dubai is the same as 93 octane in the USA. On anything better than actual 93 Octane that's all the performance you'll get out of it.


As said, the computer is listening for engine knock. With 87 it sees a lot of it and adjusts the timing advance table accordingly. With 93 octane, the computer sees very little knock, and allows the timing to be advanced until it starts seeing knock again. If you want to run race gas (110 octane), you do need a custom tune for it.
 

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The difference between running 87 and 93 in a stock untuned Ecoboost Mustang is about 40Hp less when running 87.
So well worth it to put in the 91 or 93.
 

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you do not need a tune to run race fuel. i use a locally blended race fuel called sabre chem 100 octane with the OEM tune. with race fuel you will get the maximum HP possible with the OEM tune and a custom tune should yield more. since we only have 91 octane at the pump, i opted for the race fuel. i use the OEM tune because it is safe. the same reason i use race fuel. i'm running the engine about as hard as you can run one and i want it to last. i'm in an R & D frame of mind. most of the racers said it wouldn't work. not only does it work, it works well enough that some of them are complaining to officials. 20K takeout with 26 races on it. 10 wins so far...
 

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Mine has a warning on the inside of the filler door stating that the car requires 91 octane fuel, with the Ford Performance tune I run nothing but 93 octane (we don't have 91 in our area), it runs real good!
 
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The tuning strategy advances timing until it encounters knock then backs off.

If the knock resistance of the fuel is high enough the timing will advance to the highest number on the table.

Igniting the fuel earlier allows more of the gas expansion energy to be transferred into downward force on the piston, igniting the fuel later causes the explosion to expand after the piston has already started to travel downward which wastes some potential power. The problem is that igniting earlier increases pressure and increases risk of knocking so with poor fuel the timing is retarded to protect the engine from knock.

There is a spark retard multiplier applied to the timing table.
If the timing can max out consistently with out any knock occurring the multiplier moves to negative, if knock is encountered before timing can max out the multiplier moves to the positive.
Since this is a spark retard multiplier a positive value will increase the amount of spark retard and a negative value will decrease spark retard meaning more timing advance will be allowed.
This system is called a few names and is used by a few manufacturers, on the ecoboost it is generally referred to as OAR or octane adjust ratio.

Sent from my SM-G960W using Tapatalk
 

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Someone please explain this mess lol.

Thanks
It sounds like you have a limited understanding of exactly how engines work, so explaining this in a way that is useful to you may be difficult. But let's try.

In the most basic terms, lower octane fuel ignites at lower temperature/pressure. The term "timing" in reference to ignition is when the spark plug fires to ignite the fuel/air mixture in the cylinder. You can increase power output by igniting the mixture earlier, giving the expanding gases more time to press on the cylinder. More power, however, creates more heat. If you create enough heat you can get uncontrolled ignition.

Uncontrolled ignition can happen before, during, or after the spark plug fires. When portions of the mixture ignite at the same time or after the spark plug fires then you get two (or more) flame fronts in the cylinder at the same time. When those flame fronts collide you get a knocking sound. That's called "detonation." If uncontrolled ignition occurs before the spark plug fires it's called "pre-ignition." Detonation is bad, and it can cause increased wear on internal engine parts. If it gets bad enough it can cause damage. Pre-ignition is the engine killer. If ignition occurs too soon the expanding gases will push down on the piston while it is still traveling upwards on the compression stroke. So you would have all the momentum of the turning engine pushing upward on the piston against the expanding gases of an early ignition. That will absolutely break things. Expensive things.

So, getting back to octane. The computer incorporates a sensor that can "hear" knock events, which are often a precursor to a pre-ignition event. Lower octane fuel ignites at lower temps, causing detonation. When the computer hears the knock it changes the timing to reduce power output. Higher octane fuel is more resistant to uncontrolled combustion, so the computer allows the timing to advance further, which allows the engine to generate more power.

The bottom line is you do not need a special tune to realize power gains by using higher octane fuel. Octane is computed differently in different parts of the world, but your owner's manual explains the difference.

There are any number of sources online that can further explain the particulars. Look around a bit and check back if you have any further questions.
 

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Have a quick question. My 2019 ecoboost was just taken in and diagnosed with 98 octane ads the PROBLEM... I had put Lucas octane booster in at a fill up and the car was thrown into limp mode. I took it to the Ford dealer for them to tell me the fuel was the problem. Ok, now, tank drained, fuel system cleaned out 600 later and now they detect a KNOCK, and potentially be cylinder melting/ might need motor??? Per all of these messages, 98 shouldn't be high enough to cause this damage, and it was only driven once after thrown into mode, so shouldn't be long enough to even cause extensive damage...have never dogged the car at all...so why would this do this damage? Or could it? Please explain...
 

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Putting in anything commercially available at the pumps even upto 100 octane (yes we have that here) shouldn't do anything detrimental to the engine. Adding octane boosters are a bit hit and miss and have always considered them snake oil. Maybe I'm old school but that may have actually had a negative effect on the fuel.

Interested to know how the garage come to the conclusion the fuel was the issue. Did they test it? What was the result? Or did you tell them you put a booster in and that lead them to the conclusion that it was bad fuel?

I've learnt NEVER give a dealership or garage too much information. Let them figure it out themselves and show there workings.
 
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Putting in anything commercially available at the pumps even upto 100 octane (yes we have that here) shouldn't do anything detrimental to the engine. Adding octane boosters are a bit hit and miss and have always considered them snake oil. Maybe I'm old school but that may have actually had a negative effect on the fuel.

Interested to know how the garage come to the conclusion the fuel was the issue. Did they test it? What was the result? Or did you tell them you put a booster in and that lead them to the conclusion that it was bad fuel?

I've learnt NEVER give a dealership or garage too much information. Let them figure it out themselves and show there workings.
Yes, unfortunately I told them upfront. I never would have believed a one time octane booster would ever have caused that damage...repeated maybe but...once limp mode came on, I shut her down and took her in.They.proceeded to tell me there was no such system to reduce spark knock. I've seen may comments on this site alone about this system...very disappointed in my dealership
 

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I have so many questions.

Sounds like they are trying to blame you as an easy way out for them

I would be asking how/what they did to come to that assumption aside from your admissions. What tests did they carry out pre the drained tank did they carry out any tests on the fuel they drained. How did they clean the fuel system? What test did they carry out after the work they did? Was it running fine when they returned it?

Is the melted piston new engine a diagnosis from the dealership that doesn't no about the basics on how why or when these engines advance or retard the engine?

Can you take it to another dealership?

Have you got the service reports for the work recommended/completed so far?
 

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I have so many questions.

Sounds like they are trying to blame you as an easy way out for them

I would be asking how/what they did to come to that assumption aside from your admissions. What tests did they carry out pre the drained tank did they carry out any tests on the fuel they drained. How did they clean the fuel system? What test did they carry out after the work they did? Was it running fine when they returned it?

Is the melted piston new engine a diagnosis from the dealership that doesn't no about the basics on how why or when these engines advance or retard the engine?

Can you take it to another dealership?

Have you got the service reports for the work recommended/completed so far?
Still haven't heard back from the dealership. They are running further diagnostic. And apparently he was not too informed on the systems for the
Fuel. I will most definitely take it to another dealership and hopefully they will not have reported the Vin to Ford, to nullify my warranty.
 

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Still haven't heard back from the dealership. They are running further diagnostic. And apparently he was not too informed on the systems for the
Fuel. I will most definitely take it to another dealership and hopefully they will not have reported the Vin to Ford, to nullify my warranty.
This couldn't nullify your warranty for various reasons. But first off the manual itself never gives a maximum octane rating to use only minimal. Taking directly from the manual

For best overall vehicle and engine
performance, premium fuel with an octane
rating of 91 or higher is recommended

By this you followed the recommendation and can not be faulted.

Second higher octane would not have caused that problem and they should know this. Once the maximum tables are met no matter how high the octane is it will not continue to advance timing for more gains.

Btw the manual statement above is Technically a reference to the ECU ability to learn octane and many newer model cars have this not just the ecoboost line. Ecoboost just push a little futher.

Magnuson-Moss would be easy to use in this case if push came to shove as nothing you stated could have caused the problem.

Sadly its a coincidence and it just so happened to take place at that time. And yes the dealer is trying to use your statement against you to forfeit the repair and get extra $$ just like a cop will try to incriminate you from what you divulge.

Know the facts of what can and can't cause that damage. be strong about ensuring the liability is on them and arm yourself with your rights. And if push comes to shove make them prove the booster was at fault which if they continue to refuse will have to do if you strongly pursue it.
 

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When it comes to timing more only helps to a certain point. To get maximum power and efficiency you want peak cylinder pressure to occur at approximately 20 degrees after top dead center. In order for that to happen you have to ignite the mixture before then in order for there to be enough time to reach max cylinder pressure at the ideal point. If you have to much timing the pressure will occur to soon, not enough timing peak pressure will occur to late.

Octane factors into the timing because lower octane fuels ignite and burn more irradically than higher octane. So to get peak power you need a high octane fuel that has a smooth build up of the burn so peak pressure occurs at the correct point.

Dave
 

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Yea timing is fluid and always adjusting in modern cars. When it goes negative then you are getting knock and reducing power.
 

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Can’t say i have ever seen a negative number but I don’t watch it much. I use sams club and Costco and it’s always been -1.00 so even though it’s a dollar cheaper than everyone else for 93, it scores perfect to my car
 
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