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Old 12-17-2012, 05:17 PM   #1
aernan
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How much better is 93 octane vs 91 octane

In California we have only 91 octane available :mad: . At a local station I can get 100 octane. Will the ECU detect the change in fuel if I run a single tank?

In states where you can buy 93 is it obviously better?


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Old 12-17-2012, 06:38 PM   #2
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A tuner (you can guess which one :)) on another forum was kind enough to post their results from baselining the stock tune with 87 and 93 octane. It's not exactly what you asked, but you can imagine 91 splits the difference.



I don't know whether the ECU can advance the timing enough to make 100 worthwhile. It will adjust to whatever you put in the car, but it does have hard bounds.

Last edited by lddavis; 12-18-2012 at 01:19 PM.
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Old 12-18-2012, 02:14 AM   #3
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sorry the image is missing.
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Old 12-18-2012, 01:20 PM   #4
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Hm. Works for me, but probably only because I'm registered on that forum. I've copied the image to another place on the web which should be publically viewable. Let me know if it still doesn't work.
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Old 12-18-2012, 01:47 PM   #5
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yeah that works. Thanks.
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Old 01-02-2013, 05:21 PM   #6
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I have been running 93 octane ever since the first tank of gas the dealership filled me up with. I believe I was using 83 prior to 93 but I may have that octane rating wrong. I didnt see much of a gain in MPG....I would say perhaps 1 - 3 MPG on avg depending on my driving and the weather.
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Old 11-24-2013, 09:57 AM   #7
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manual says octane 87 is fine, but do you guys all get 91? it will run better when you drive hard huh?
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Old 11-24-2013, 11:25 AM   #8
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Quote:
Originally Posted by okaythen View Post
manual says octane 87 is fine, but do you guys all get 91? it will run better when you drive hard huh?
87 octane is the minimum octane rating required and is the basic recommendation. 93 octane will provide increased performance and allow the engine to advance timing to take advantage of the additional resistance to knocking provided by the fuel.

The published power gain by Ford is around 9 HP (243 hp/270 lb-ft of torque on 87 octane, 252 hp @270 lb-ft of torque on 93 octane), and on some of the at the wheel dyno reports places like cobb were putting a baseline difference of closer to 20 hp on the different octane ratings.
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Old 11-25-2013, 05:41 AM   #9
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Quote:
Originally Posted by suss6052 View Post
87 octane is the minimum octane rating required and is the basic recommendation. 93 octane will provide increased performance and allow the engine to advance timing to take advantage of the additional resistance to knocking provided by the fuel.

The published power gain by Ford is around 9 HP (243 hp/270 lb-ft of torque on 87 octane, 252 hp @270 lb-ft of torque on 93 octane), and on some of the at the wheel dyno reports places like cobb were putting a baseline difference of closer to 20 hp on the different octane ratings.

wow thanks a lot! 9 to 20 hp difference! definitely need to use 91 then. Actually here in vegas we only got 91, are there any reports of how many hp for 91 octane?
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