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GT Owners - fuel grade?


kraegar

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For a stock GT, with the stock tune, Ford's website lists 87 unleaded, aka regular, for the fuel to use. Is there any benefit to using 89 (plus) or 93 (premium) without first getting a tune using an SCT2 or similar? Any harm? Any change in performance?

 

Thanks,

 

- Tony

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For most cars, once they drink the good stuff, you can't go back.. i would stick to the 87 unless you have an explicit reason not to.

 

 

 

 

Alan???? Put down the Alice Cooper albums and extinguish that weed, son! Sure you can go back. Granted, you may not want to, but you can. :D

 

Without a tune, anything above 87 is a waste of money. You will see no improvement in performance. In fact, and chime in here if I'm wrong, I believe you'll see a slight decrease. The danger is tuning for 93 and then throwing in 87 and not restoring the 87 tune (or adding an octane additive).

 

I know of a few people who like having the ability to switch between 93 and 87. (Long trips where they're not sure if 93 will be available, they'll load up on 87 and restore the 87 tune.

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Alan???? Put down the Alice Cooper albums and extinguish that weed, son! Sure you can go back. Granted, you may not want to, but you can. :D

 

 

 

From my own personal experience, unless you have a tune for beyond 87, if you pump in a midgrade for a period of time then try and switch back to 87, your "user" of a car can't deal with it very well. It got high on the good stuff and will run crappy on the 87. Like going from Sam Adams back to Coors Lite...You car is like "this is P**swater"...Oh, and I would appreciate it if you would retract that "weed" comment as this ex-NSA spook cannot afford the association of left handed cigs and myself... :-)

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  • 2 weeks later...

From my own personal experience, unless you have a tune for beyond 87, if you pump in a midgrade for a period of time then try and switch back to 87, your "user" of a car can't deal with it very well. It got high on the good stuff and will run crappy on the 87. Like going from Sam Adams back to Coors Lite...You car is like "this is P**swater"...Oh, and I would appreciate it if you would retract that "weed" comment as this ex-NSA spook cannot afford the association of left handed cigs and myself... :-)

 

 

 

there is some truth, as cars have a little learning function in the ecu. but you can reset the ecu normally with a simple discharge of power, by taking of the negative battery terminal for 5-10 minutes.

 

now using 93 in a 87 octane car is a waste. it might get a slight kick out of 89 if it learns that it can keep timing higher.

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The way the timing tables and knock sensors are set up in the 05+ GTs there is a slight benefit to running 89 oct, or something in between 89 and 93.

 

Run your car on 87 if it does not bing. I work for a major oil company and there ia absolutely no advantage to running a higher octane unless there is compression mods to the engine.

 

Whatever you do is stay away from the E85 fuels. Use only unleaded fuel or unleaded blended with a max of 10% ethyl alcohol.

 

 

In addition, stay away from premium in Canada. It contains more metallic additives than regular grade fuel. Metallics will screw up the emission system

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Don't waste money on octane that your car can't use. That said, I bought a Diablosport Predator tuner and installed the 91 octane performance program which bumps up the fuel trim, spark advance, shift firmness, etc. in my GT. I have to run 91 octane now (or I could use their 87 octane performance tune, which works pretty good). Definitely the best mod money I've ever spent! For those of you with 05-07 GT's, you gotta get one! The car feels 50hp stronger, but my butt-o-meter is certainly over-estimating the real power gains. The manufacturer claims up to a 27hp gain, with typical results in the 15-20hp range. With the tweeks I made to the program, I likely got a 20-25hp bump. And while 91 octane costs more than 87, it only works out to about $4 more per fill up, and I only fill up about 3 times per month, so the extra cost is negligible for the great power gain there is to be had.

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