maloce

I was looking through my manual and it say 87 for the V6 but 91 or more. I got pretty much a stock(well premium). Will it really make much of a difference since it isn't hooked up or anything?

S197winstang

It will make a huge difference if you have a tune set for 91 or any performance mods that you want to get the most out of. If you are a daily driver with NO mods then 87 will be just fine.

Gene K

Im not really following what your saying about the manual. But when the 2005 was introduced the Powertrain Engineer present said that the engine actually made 3-5 bhp more on premium on the dyno. About 3 rwhp seems to about the difference Ive seen quoted from some tuners from results on stock 2005-2009 cars on the dyno. It might be worth 0.03-0.05 in the 1/4 but I doubt it makes a lot of difference in these cars under lighter load. I didnt start running Premium on the street in my '07 until I got a tune.

The 2010+ cars can take more advantage as they now have specific maps in the PCM for Premium designed for the Bullitt. What this means is they run more timing when running Premium resulting in more power and better mpg. Running 87 wont hurt it just cost you a mile or so per gallon and slow the car down a 0.10 or so in the quarter.

Lito

A 05-08 car with the stock tune won't get any advantage from 91oct or 93. Their maps are done for 87 as every other Ford car that do not require premium.

Only the bullitt came with the adaptive knock strategy, the normal 08 GTs didn't.

To the OP, keep using 87 until you get a tune for your car.

ski

+1 on using 87 octane if the engine is not tuned for a higher octane, and it's also not pinging. But if it's pinging, then you may want to use 89 or higher octane to stop the pinging and prevent possible engine damage, if other options do not help(different brands of gas, and additives that eliminate carbon build up like Seafoam or Techron).

I believe 2010 is the 1st model year for the Mustang GT to have the same "octane sensing" software that the 2008+ Bullitts use.

Nuke

IF there's any gain it'll be so small that you'll never feel it. As mentioned above, our PCM's cannot adjust for the higher octane so you're basically throwing your $$ away unless you're tuned for it.

maloce

I think I forgot to mention it but I have a 2010 premium automatic. The manual says it benefits more from 91 octane or more.(I can only seem to find places selling 87,89, and 93 here in Texas).

I read some reviews saying it will increase my torque, but will I really notice a difference if I slam the pedal down on the highway or at a stoplight?

Nuke

One way to find out: Drive the living crap out of a tank of 87, then fill up with 91 or higher and then drive the crap out of THAT tank. Then let us know.

Thanks for clarifying that it's a 2010 (although your info says 2008). That DOES make a difference.

Gene K

The pre-2010 may not "adjust" for it but many cars do bump the knock sensor on occasion under heavy load. Higher octane eliminates this. However I dont think their is enough benefit to bother with anything over 87 unless unless you are racing or dynoing.

TheMadScientist

1-2mpg and ~2 degrees of timing added. Just from going from 87 to 93. Logged with an OBD2 CAN bus scanner on a stock 2005 GT.