When I took delivery of my 2012 GT last Friday I can only imagine when the dealer filled it up they did so with 87 octane. I have been trying to research how long it will take to increase the power from the supposed 400 on 87 octane to whatever mine will be with 93 octane. (412, maybe more since that is rated on 91?)

I read one thread where someone said as much as a 1/2 tank because it will very slowly add timing back in.

Anybody have any idea how long? I have gone about 60 miles and I cannot tell a difference in performance.

 

You won't be able to "feel" the power difference between 87 to 91. It's there, but you won't feel that small of a HP increase.

When I bought mine in March the dealer filled mine with 86 octane. Yes, here in this sorry *** state, our octane ratings are 86/88/90-91. It has been around 105+ degrees here everyday. I run 90 octane for piece of mind. I also could not tell the difference in the HP increase.

 

when i took delivery of mine i specifically asked what they filled it up with and my salesman said it was 87. i've been running 87 since, filled up 4 times already with it and i have not noticed any lack of performance. i won't be taking this car to the track so i don't need 91 or above; i also don't plan any performance mods or tunes that would require 91 or above.

 

Why do you think they put in 87? Did you ask them?

 

I may be going out a limb here, but I would assume that virtually all auto dealerships that store gasoline on their dealership lot only but 87-octane fuel. I've not seen many dealerships that have more than one fuel tank on their back lots, and unless the salesman or make-ready guys are sticklers to get 91+ octane fuel in the Mustangs, I would almost always assume that the cheapest fuel available is what they used to fill the tanks.

The exception would be the high end auto dealerships that sell high-end cars like BMW, Mercedes, Porsche, etc.

 

I have read 6-10 whp, and even ford claims 12hp/13ft-lbs, I have also heard the increases are greater through the curve as those are peak numbers. Thats probably something I could feel.

I agree my car ran great on that first tank of 87, it felt strong, but I have nothing to compare to. (and neither do you) If my plans were the same as yours I'd agree. Although I already have a couple grand in parts waiting to go on and I want to baseline this car at the track this week. I want to make sure it's at least making the most power it can stock. If I have to drive it longer I will.

I did not ask them, although my friend works at a dealer nearby and he said he was told to always fill up with 87, even in cars that say "premium fuel only". I don't see why a dealer would spend extra money on gas, especially given the car wash boy who was sent to fill it up. I doubt he even knew the octane makes a difference in these cars. Judging by the attitude of the management/sales people I am confident he got the same instructions as my friend.

Besides most people think if its not turbo it's not faster on premium. Which is true on 90% of cars.

 

Bought my 11 on 10/4/10. I put 91 in it prob 1st 7 months? I averaged prob 18 MPG? I now only use 87. Last fill up I got 24.6. Also when I 1st started w/87, my MTE was around 268? Last was 324. I can't tell a bit of power decrease on cheap stuff.

 

this

 

They're not putting 87 in the 500 or someone would get their butt kicked. As for you 302 boys, if you're filling up once a week it's like 3.00 more per fill up and 166.00 a year. I guess if you need that 12.00 a month on something else and don't care if you have 402 hp against 412 hp than go with the 87.

 

Dont be concerned, you will be able to feel the difference (although very slightly) once your car is properly broken in. remember its still brand new.

 

Yeah I could see that, my car only has like 280 miles on it now.

 

+1
I ran 87 for the first 3 fillups until I read the difference in HP between 87-91. When I weighed out my options for ratings vs. cost, I realized I was only spending an avg of $3 more per fillup going with 93. I've used 93 ever since. It took about a tank to really notice any difference. The main difference I can actually feel is in the higher rpms, it feels like it pulls harder on higher octane at 5k+. I've also noticed a little better mpg's if that matters.

 

Think it might be better if you DIDN'T try to push it to 412 HP (or even 400 HP) right off the showroom floor, unless you want to test Ford's warranty system... Just sayin'

Have run both 87 and 91, and with 3.73s, could tell no real difference till 4th, 5th or 6th, and that wasn't huge, as the aerodynamic drag steals a lot of HP at those speeds.

So far, have yet to NEED that "extra" 12 HP, so I have voted for saving the $$$ and running 87 octane.... The car still runs like a raped ape with low octane fuel..

 

I work for a FORD dealership and we don't even have premium pumps... It's all regular, in every car, all day... And that is def the norm in the business.

 

It's only 10 not 12, just saying.

 

Are you saying your dealership is putting 87 octane in an engine that REQUIRES 91+? what's the name of this dealership?

 

Could you please state the octane number you use for GT500's...Thank you...

 

Why the eff would I wait to "push it to 412 hp"? That's exactly why the warranty is there. If this thing is gonna break I want to know now, not after I have had it for a year. I'm not pushing anything anyway, that's what it makes from the factory. Modding it would (will) be pushing it. I'm not personally interested in people who don't "need" the extra 12 hp. I paid for it, I want it. Especially when I am racing someone. If you guys are too pansy to race go drive to work or get groceries I don't care, my question was how long does it take for the computer to add the timing back in. I also don't care if anybody can feel the difference, its a fact the motor makes more power on premium fuel.

Exactly.

They all do, I said in my earlier post that my close friend who fills cars up for a dealership fills EVERYthing with 87, even cars that require premium fuel.

 

It's 10 not 12 and I guess I'm glad I ordered my 500. Saying they all do because your friend does is a little out of left field.

 

86 octane lol. I didn't know such a thing existed. I wouldnt put that in my lawn mower lol.