What octane do you use

[mada808]

I don't know why someone would buy a 400+ horsepower Mustang GT and not run 93... but I guess that's none of my business.

Because some people don't care about the minimal decrease in power. I use 93 just because the cost doesn't affect the wallet much since I don't drive much.

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[Tugger50H]

93 or e85

 

[ITSMEPAUL]

Your wasting your money on high octane.

Unless your taking it to the track. Save your money.

 

[Hashbrownn]

So I'd be losing 5HP up top and 30-40HP in the mid-range by using 87 octane? I'm guessing that's at the crank? So.. actual HP loss at the wheel would be like 10-15HP? Can someone correct me if I'm wrong?
Where I live, the price difference between 87 to 93 is almost a 75cent to $1 a gallon.
I won't be getting enough increase in MPG with premium to justify it.
And for all of you that wonder why I would by a 434HP car and put 87 in it? I never get to use any of that power putting around town doing 25-35mph, and honestly my butt dyno can't tell the difference.

 

[Spartan]

Most premium cars will run on 87 too... the engine will adapt. In high altitudes it's almost necessary to run a lower octane.

I don't know why someone would buy a 400+ horsepower Mustang GT and not run 93... but I guess that's none of my business.

Not Audis or BMWs...they state on the door label premium required.

Because you don't need to run 93. The manual says the engine is rated at 87 and is recommended.

It's right here in the manual. They also state for improved performance they recommend premium.

But again, it's rated for 87 and you only lose 1% HP stated by Ford Engineers running 87. The HP figures are on premium so they can boast with the highest # possible.

Now the EB on the other hand takes a massive power hit running 87.

 

[jasonstang]

Well, Ford also says OEM tires are recommended.
I look at compression when choosing what octane to use.
If it's above 10:1 = 91 octane
9:1 = 89 octane
8:1 = 87 octane

 

[andrewr164]

I switch it up every half tank between 93 and e85 with the Livernois flex fuel tune..:first:

 

[whalesalad]

The only way to really put this to rest is to dyno a car on 93, run a few tanks of 87 through it to allow for adaptation and an accurate fuel octane percentage, and then re-dyno. Everything else is just anecdotal or assumptions.

 

[Zelek]

Has anyone done a knock sensor test while running 87-89 octane? Just curious to see if there is any at all when stepping on the gas pedal. That's the only thing I'd be interested in seeing. If there's no knock, then 87/89 is just fine while stock. Tuning is a different story.

 

[redline727]

Has anyone done a knock sensor test while running 87-89 octane? Just curious to see if there is any at all when stepping on the gas pedal. That's the only thing I'd be interested in seeing. If there's no knock, then 87/89 is just fine while stock. Tuning is a different story.

I can see a difference knock and timing in data logs just from running the shittier 93 found around here in the winter compared to top tier summer fuel. Thats why I run the Lucas octane booster in the fall winter months combined with top tier 93 and knock goes away and timing is restored. So I imagine you would see the same effects on a stock tune stepping down to 87 from 93 if you data logged. Hell I would guarantee you would see a difference. No way you will see 26*+ spark advance on 87 I wouldnt think. The knock doesnt mean its bad it part of the logic to adjust timing for the lesser quality fuel. Thats how Lund Jr explained to me the stock tune works when changing octane levels.

 

[tcman54]

Typical dude making a youtube video with some inaccurate stuff I think, but he did real world runs, with the 93 compared to 87 he shaved about 3/10th's of second off of his 0-60 times. Was all of his runs similar, not sure, is that kind of timing difference worth spending the extra money on gas, who knows, lol.

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[Spartan]

Typical dude making a youtube video with some inaccurate stuff I think, but he did real world runs, with the 93 compared to 87 he shaved about 3/10th's of second off of his 0-60 times. Was all of his runs similar, not sure, is that kind of timing difference worth spending the extra money on gas, who knows, lol.

Nope...not worth it unless you're a racer. Ford has stated that you get more HP/TQ on 93...hence the * on their website.

But there isn't any other added benefit to run 93 since the engine was designed to run on 87. It's in the manual, it's on the door, hence the 87 number. If it was made to run on 91/93 there would be a sticker for that and in the manual like Audis have that require premium. They aren't going to let you put in 87 if it's going to F up the Coyote...otherwise it would state required 91/93 on the door/manual. 87 is fine for the majority of owners.

 

[jon2002]

Can any GT owners notice the performance gains from 93 octane from behind the wheel?

11:1 compression ratio aint much nowadays. My 2014 Mazda6 engine has a 13:1 compression, and it requires and recommends 87 octane.

 

[xArchangel79]

92 just because stock hp ratings are based on 93. I bought an expensive (for me) sports car, I want to get everything out of it that I can.

 

[jasonstang]

Can any GT owners notice the performance gains from 93 octane from behind the wheel?

11:1 compression ratio aint much nowadays. My 2014 Mazda6 engine has a 13:1 compression, and it requires and recommends 87 octane.

But your Mazda 6 is direct injection isn't it? Compressing air to 13:1 is fine but compressing air/fuel mix to 11:1 compression can cause preignition if octane is too low. However your clever computer is constantly listening to pinging and adjusting your intake and exhaust cams to run the engine on a reduced compression mode by closing intake valves early as well as retarding the spark so your engine do not explode. The side effect is reduced performance and a not as optimum burn. It will run but you will get worse fuel economy and hopefully the ECU is catching all the pinging. I prefer running the engine on a fuel that's least possible of pinging and minimum spark retardation most spark advanced and maximum compression for most efficiency.
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