Hey guys,

I have a bonestock, 2010 mustang gt. I've been using 87 since i've gotten it, and now plan on using 93. I don't have a tune or anything, however are there any precautions I should take? I plan on waiting until the car is as close to empty as possible before filling it with the 93, is that good?


Maybe a dumb question, I was just wondering if theres anything i need to do differently since I don't have a tune.

 

Without a tune, you don't need to do anything differently. Don't even need to wait until the tank is empty. I tried this before I got a tune and noticed a little better mileage and a very modest power increase. It really isn't necessary to run premium unless you have a tune, the factory computer will compensate for all gas octanes. Good luck.

 

Gotta agree..

 

The only thing to prepare for is spending more money. It's all about the tune. Even a custom 87 octane tune will out-perform the stock 87 tune. Putting anything other than 87 octane in the tank without a tune is pointless. The Bullitt and the 10's (which have the Bullitt tune) will gain a few minor RWHP from higher octane but not near as much as a custom 87 tune will gain.

 

Unless the car is running sluggish. Even the owner's manual says to run 87 unless the car seems to not be running smoothly. Then run higher octane.

 

2005-2009 has 25 degrees of timing.

The "mailorder tunes" for my 2007 had 26 degrees for 87 octane and 29 degrees for 93 octane. Ive seen custom tunes as high as 30.5 degrees for 93 Octane on some cars.

2010 has 27 and under some conditions 28 degrees of timing. Im not sure of the exact conditions that allow the extra degree. I suspect the car needs more than 87 octane but especially as rich as it is stock may run just as well on 89 octane as 91 octane.

Wait till it gets down to a half tank and fill it up with 93 octane.

 

Please tell me this thread is a joke....

 

There is very little power advantage to running a higher octane in a stock car/tune. As stated, you'll just be wasting money. If you're after the very slight power advantage, odds are that your mileage will go down just because of the spirited driving.

 

Sorry, I jumped the gun on that. For some reason I missed the OP and thought you were talking about a Custom tune not the 2010 factory tune, blonde moment, lol

 

My bad; I see now that you have a '10 which does have the same stock tune as the Bullitt. I believe your OM will indicate that you will benefit slightly from the higher octane but as I stated earlier, a custom 87 tune will run circles around your stock tune with 91 or 93.