What octane do you use

[BmacIL]

Theoctane has nothing to do with "explosive". It is a term to define how long it burns, or the speed it burns. IIRC, you want a flame front to progress 33ft/sec.

This. The higher the octane, the slower the burn.

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[jasonstang]

So are any of you guys running on higher than 95RON? If so is it worth doing? Shell power is rated at 98.5RON and tesco do a 99RON fuel. I was planning on using those two but it sounds like the coyote doesn't demand the highly explosive stuff to run cleanly.

87AKI = 92RON
91AKI = 95RON
93AKI = 98RON

I think anything above 91AKI on stock tune is not gonna have any gain given it's compression.

 

[jasonstang]

This. The higher the octane, the slower the burn.

Actually that is not true either. Octane has nothing to do with how fast/slow the fuel burns.
Octane is only how easy one fuel will self ignite at certain temperature. Higher octane the better the fuel will resist self ignition at higher temperature.
Once the fuel is ignited by the spark, it will burn at the same rate.

 

[v8hgt]

87AKI = 92RON
91AKI = 95RON
93AKI = 98RON

I think anything above 91AKI on stock tune is not gonna have any gain given it's compression.

Thanks that clears things up perfectly. I thought the figures being quoted looked a bit low ;) now I find out we were using different units of measurement. Doh!

 

[daytripper]

Actually that is not true either. Octane has nothing to do with how fast/slow the fuel burns.
Octane is only how easy one fuel will self ignite at certain temperature. Higher octane the better the fuel will resist self ignition at higher temperature.
Once the fuel is ignited by the spark, it will burn at the same rate.

This. Anyone interested should google octane and do some serious reading.You will be more knowledgeable and somewhat confused.

 

[mustang1]

All it takes is one missed pre-ignition not detected by the knock sensor and boom goes your piston.
I would rather use a fuel that will completely eliminate possible pre-ignition at any time.

Owners manual says all three Mustangs supports 87 octane. Ford engineers and the Ford bean counters back that up with a 5 year / 60,000 mile power train warranty.

Since Ford has a lot money on the line, in terms of warranty, I don't expect that they are that worried about one missed pre-ignition permanently damaging the engine.

Now if one gets aftermarket 93 tune and then gets a tank of 87 for some reason, that's another story.

That said,
60,000 miles / 20 mpg = 3000 gallons * $0.5 (for premium) = 1500 / 60 months = $25/mo

Not much in the scheme of things.

 

[Lost]

Actually that is not true either. Octane has nothing to do with how fast/slow the fuel burns.
Octane is only how easy one fuel will self ignite at certain temperature. Higher octane the better the fuel will resist self ignition at higher temperature.
Once the fuel is ignited by the spark, it will burn at the same rate.

Uh, no. Big difference between and explosion and a linear flame front. While pre-ignition can lead to detonation.

 

[jasonstang]

Uh, no. Big difference between and explosion and a linear flame front. While pre-ignition can lead to detonation.

That's what I sad lower octane will much easier to pre-ignition compare to higher octane at higher temperature. Flame speed will be the same.

 

[Lost]

That's what I sad lower octane will much easier to pre-ignition compare to higher octane at higher temperature. Flame speed will be the same.
Actually ethanol being much much higher octane rating has a slower flame speed.

Normal combustion has a much slower flame front.
Detonation, not so much.
https://en.wikipedia.org/wiki/Deflagration_to_detonation_transition

 

[shahram72]

Oh for sure I'm no automotive engineer, but I do know, and many others I'm sure, that when you have engine knock or ANY deleterious effects on 87 and you ru 93 and they are gone, better to run 93 and be safe. Cars are expensive and I don't believe in pinching pennies. We Mustang owners are performance oriented and want the maximum potential from our cars. Why would (most of us anyways) want to run lower octane and lose power and mpg. I felt the difference on my Acura(which was rated for super) and not so much on the V6 Mustang, which is probably the engine most suitable for 87. I notice a bit better mpg on super. Doesn't that say anything? Run what you want, probably wont be a problem, but 310hp out of 2.3L, that's damn impressive, getting a lot out of that motor. I would just like to be proven wrong and see those motors last beyond 100K miles.

 

[Lost]

Oh for sure I'm no automotive engineer, but I do know, and many others I'm sure, that when you have engine knock or ANY deleterious effects on 87 and you ru 93 and they are gone, better to run 93 and be safe. Cars are expensive and I don't believe in pinching pennies. We Mustang owners are performance oriented and want the maximum potential from our cars. Why would (most of us anyways) want to run lower octane and lose power and mpg. I felt the difference on my Acura(which was rated for super) and not so much on the V6 Mustang, which is probably the engine most suitable for 87. I notice a bit better mpg on super. Doesn't that say anything? Run what you want, probably wont be a problem, but 310hp out of 2.3L, that's damn impressive, getting a lot out of that motor. I would just like to be proven wrong and see those motors last beyond 100K miles.

If the car was designed for super, you WILL notice a significant hit on mileage, power, etc running lower octane. It's pulling timing to avoid ruining itself. This is a horse of another color. But hey, run what you want. You will not hurt the car running what the engineers spec'd it for, despite internet engineers telling you otherwise. You do run a chance, however, if you run under spec fuel in anything. So if you had a car spec'd for 91, you best burn that stuff.

 

[Hashbrownn]

ROFLMAO!! :lol:
I love the folks that question what others do to their car or what they feed it, then judge them for their choice.
Performance Engine?? PLEASE~ I bought my Mustang to use as a DD. If I wanted a "Performance Vehicle" I would not have picked a Mustang. I bought my Mustang to carry groceries and my golf bag. Obviously everybody has their own definition of "Performance" and I understand that. Heck, plenty of folks ride around in their 20 year old Honda and think it's a performance car... 93 ONLY!! I hear that a lot, and I hope it make you feel good inside to know that you're running the best fuel you can provide for your Mustang, but why put others down? Mustang is able to run on 87,89,91,93 or corn fuel if you want it to. It's a freedom of choice.

 

[thet33]

ROFLMAO!! :lol:
I love the folks that question what others do to their car or what they feed it, then judge them for their choice.
Performance Engine?? PLEASE~ I bought my Mustang to use as a DD. If I wanted a "Performance Vehicle" I would not have picked a Mustang. I bought my Mustang to carry groceries and my golf bag. Obviously everybody has their own definition of "Performance" and I understand that. Heck, plenty of folks ride around in their 20 year old Honda and think it's a performance car... 93 ONLY!! I hear that a lot, and I hope it make you feel good inside to know that you're running the best fuel you can provide for your Mustang, but why put others down? Mustang is able to run on 87,89,91,93 or corn fuel if you want it to. It's a freedom of choice.

Why'd you get the Performance Pack ????

 

[Hashbrownn]

Why'd you get the Performance Pack ????

I always get the highest mechanical option on my vehicles.
Does adding the "Performance Pack" make it a performance vehicle? I think not. Can I check the "Sport" option on the Fusion and turn it into a "Sports Car"?
Some silly questions. I got it cause I like it and could afford it.

 

[daltron]

ROFLMAO!! :lol:
I love the folks that question what others do to their car or what they feed it, then judge them for their choice.
Performance Engine?? PLEASE~ I bought my Mustang to use as a DD. If I wanted a "Performance Vehicle" I would not have picked a Mustang. I bought my Mustang to carry groceries and my golf bag. Obviously everybody has their own definition of "Performance" and I understand that. Heck, plenty of folks ride around in their 20 year old Honda and think it's a performance car... 93 ONLY!! I hear that a lot, and I hope it make you feel good inside to know that you're running the best fuel you can provide for your Mustang, but why put others down? Mustang is able to run on 87,89,91,93 or corn fuel if you want it to. It's a freedom of choice.

This isn't a performance vehicle? Gosh, my accelerometer may have something to say about that.

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