What octane do you use

[7.62]

93 on my DD.

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[Lost]

87 on highway miles (3000 this month alone)
91 or 93 if I will be around town. Prolly a waste though, I think it is mostly mental masturbation.

 

[Jon|3.7]

Recently 93 didn't know I could use 93 so it was on 87 for awhile! )):

 

[SpeedLu]

She drinks 93 octane. My Roush tune calls for 91, but all gas stations around here have Plus at 89 and Premium at 93, with no 91 middleground to be found. Using a higher octane fuel than is necessary for your tune is ok, but using lower octane is not. So, I waste a few more cents per gallon and fill up with 93.

 

[TricarboNate]

93, since it's the only one with no ethanol.

 

[EcoSwag1990]

87 on the tune?

Stock

 

[FordTechOne]

At the risk of talking about things I know little about - admittedly a long and growing list - I was merely pointing out that the manual says 87. I don't doubt it is setting an octane floor rather than ceiling and all of the hp and torque numbers in the official Mustang brochure were in fact tested with 93 octane (interestingly not the V6).

Yes it is a performance car. No, you can't legally go over 65 MPH. And even if you ignore the law (which none of us would ever do-right) there are very few places and rare times you can do it, especially here in JerZ. So why 87 octane? 30-60 cents a gallon and very unlikely to be any really meaningful performance loss. When I think I am going to be doing any truly spirited driving, I can always fill it with premium.

The manual says 87 because it has to. If the manufacturer "recommends" or requires premium fuel, that needs to be specifically disclosed, and can affect things like the marketability of the vehicle, etc. That is why you will typically only see very high performance models and luxury vehicles recommending/requiring premium. On models like the Mustang GT, engineering just detunes the strategy when low quality fuel is detected by the PCM (detonation) which reduces horsepower, torque, and fuel economy.

I'm not seeing how the speed limit has anything to do with it; it isn't about top speed. It's about driveability, torque, acceleration, and fuel economy...none of which require exceeding any speed limits to notice.

You say no "meaningful" performance loss? Last I checked, 30-40HP was pretty significant!!

And you can't just "fill it with premium" when you want the performance; it takes the software strategy at least a full tank of 93 to learn the new octane limits.

 

[15DIBGT]

E85 so at least 105+ Lund tune, 1.89 a gallon.

 

[113]

93. Probably not needed, but I want to eek out every bit of performance out of the engine that I can; especially while gas is still, relatively, cheap compared to how it was.

If gas ever goes back up for $4-5/gallon I'll move down to 87.

 

[shahram72]

V6 here... The one engine that should be fine on 87, and it is. But after a break in I switched to 93 and the mpg jumped 1.5mpg. It wasn't just the break in improvement, I already saw that. It changed after the refill shortly. So that tells me the computer was retarding the ignition. It runs the same, but that tells me it's better on 93, so I'm going to stick with it. Might try a tank of 87 soon to see if it drops, and that will confirm my observation. On another note, my opinion is anyone who runs a 2.3L turbo motor on anything less than super is crazy. You're not saving a dime. Plus turbo motors are super sensitive to detonation. I know my improved mpg is covering for the increased cost.

 

[Braski]

Nothing but 93 since day one.

 

[WindveilNJ]

And you can't just "fill it with premium" when you want the performance; it takes the software strategy at least a full tank of 93 to learn the new octane limits.

Great to know - check that off of the list of things I don't know - the one briefly mentioned earlier.

I will see how my car does going from traffic light to traffic light and downshifting to pass and then make a decision on gas, on higher gear ratios better rubber, etc.

 

[tcman54]

Ok, if I use 87 my ecoboost it is rated at 270hp, if I use 93 it's rated at 310hp.

Exactly what does this rating mean, besides the max amount of power the engine can output, is there noticeable gain off the line, top speed only or what?

An extra 40hp seems huge to me, why in the world am I using 87, gas is cheap, I don't drive the car much (retired) and when I do it's mostly spirited driving on 70mph highways here in Florida, 93 would seem ideal for me.

This needs to be addressed immediately, lol

Terry

 

[TruBlu16GT]

93, since it's the only one with no ethanol.

You know, that's a very good point. That's probably the major reason why some of us see a significant decrease in mileage when using lower grades. If it were straight fuel 87 or 91, I bet we would see no drop in economy.

I know in my Javelin, back when we had straight fuel and none of this ethanol blended crap, my 360/4barrel/auto got the same economy regardless of octane. However, the car would ping much, much less on Premium than Regular. That car got (and still gets) a steady 15 mpg climbing a mountain or falling off a cliff.

 

[Chameleon]

Ok, if I use 87 my ecoboost it is rated at 270hp, if I use 93 it's rated at 310hp.

Exactly what does this rating mean, besides the max amount of power the engine can output, is there noticeable gain off the line, top speed only or what?

An extra 40hp seems huge to me, why in the world am I using 87, gas is cheap, I don't drive the car much (retired) and when I do it's mostly spirited driving on 70mph highways here in Florida, 93 would seem ideal for me.

This needs to be addressed immediately, lol

Terry

Yes sir.

http://www.autoblog.com/2015/01/05/2015-ford-mustang-ecoboost-loses-big-power-on-87-octane/

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