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The last sentence is related to the others because it is part of the same paragraph, that is english grammar. If that sentence was not related it would be part of another paragraph.
Well no kidding there linked in some fashion, the header of the paragraph is "Octane Recommendations", which is providing 4 individual recommendations/warnings related to octane. Anyways, interpret how you please.






The manual is clear. Premium improves performance. Manual notwithstanding, it stands to reason that higher octane is beneficial for a car with 12 to 1 compression. There are two questions the manual and common automotive sense don't answer. First, does premium solve any of the complaints like shuddering? Some on this forum have reported that it does. I use premium and have had no shuddering or other issues. Second, is the added cost worth it? I doubt premium's added cost is worth the performance gains or MPG gain (if any -- regular may give better MPG).

So as I see it, premium is worth a try if you've had shuddering or other performance issues, or if you're a leadfoot who wants to see whether there is a power improvement.

Once I have about 4k miles, I intend to switch off premium to see how regular compares in the fuel economy department as that is my principal concern.
The way an engine is tune has more to do with the octane requirement than the compression ration does. A 12:1 carbureted engine can be tune to run on 87, it won't make near as much power as if it were tuned to run 87 due to the ignition advance you would be limited to. DI engines are quite different when tuning because all the benefits it provides, such as better atomization which leads into better air charge cooling and so on and so on. Needless to say you can run more aggressive tunes with lower octane fuels on a DI engine vs their convention fuel injected counterparts.
 

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This paragraph is providing us with 4 key pieces of information 1) You vehicle is designed to run on 87. 2) Some stations offer fuels with an octane rating below 87. 3) Running fuel with octane ratings below 87 is not recommended. 4) Running premium will improve performance.
THIS. It seems quite clear.

It certainly does not state "premium fuel improves performance ONLY in areas where 'regular' fuel with octane ratings below 87 is sold."
 

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My 6.2 Raptor was rated at 400 HP on regular and 411 on premium. Said same thing in manual about improved performance on premium.
 

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My 6.2 Raptor was rated at 400 HP on regular and 411 on premium. Said same thing in manual about improved performance on premium.
Werd, my G8 made 8 more HP running 91 vs 87.

You must live in an area where 85 octane gas is sold.
[thumb]
 

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The last sentence is related to the others because it is part of the same paragraph, that is english grammar. If that sentence was not related it would be part of another paragraph.
Have to say I agree with JSR84. Once the period is used, the next sentence does not have to follow directly, and it sounds like two different thoughts. Having said that, Ford could have made this a lot easier by being more specific in their recommendation, or just leaving it out. The language makes it very difficult to interpret.
 

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Premium did nothing for my shift into 4th gear shudder. No other gears exhibit this on my DCT, with Oct. flash.

87 works fine for me. Parsing and linguistic analysis does nothing to improve my gas mileage. Keeping my foot out of it does. Try it.
 

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Have to say I agree with JSR84. Once the period is used, the next sentence does not have to follow directly, and it sounds like two different thoughts. Having said that, Ford could have made this a lot easier by being more specific in their recommendation, or just leaving it out. The language makes it very difficult to interpret.
I think we're giving the authors and editors of the Owner's Manual way too much credit. After all, mine says that if you drive economically your message center flower will display more "pedals".

I doubt the sentence structure in the fuel grade discussion is intentional, leaving us to wonder what they meant.
 

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Here in missouri, most gas stations provide 87,89, and 91. 91 being premium and 87 being regular.

I've taken a few trips around the state, and used some of the different gasoline for my car. I've noticed that in the more metropolitan areas, the 87 is fine and will yield close to 400miles a tank with 60/40 hwy/city driving. In the more rural areas, i found the the 87 to be trash, remembering a trip from southern Missouri up to Columbia to give me only 330miles on the tank, even though it was 70/30 hwy/city. (granted, my comparisons are using most likely some summer and winter blends)

Then however, i came across a gem of a gas station. A shell ~6 miles away from me sells 91 no eth (premium no eth), and if I don't get 400miles out of a tank, or at least close to it, i know i'm doing something wrong, and that's not exclusive to 60/40 hwy/cty, it ranges 40-60/60-40.

What i'm trying to say is, if you have access to no ethanol gasoline (most of the times it will be sold as premium), go for it.
 

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This also brings up the question..which brand of gas is better? Do you find that different brands are better than others? So far from my findings I get the best fuel mileage if I stick with Shell Regular. Chevron/Texaco second. If I go with any other brand, my gas mileage seems to go down a little.

I also bought the Focus so I didn't have to burn mid grade or premium gas. My previous car (2002 Jetta) ran sluggish if it burned regular.
I had a fuels class in school that opened my eyes... I wrote a little thread about gas quality and linked to the Top Tier website: bookmark their list in your phone or something, because that list changes frequently!
http://www.focusfanatics.com/forum/showthread.php?t=279379
 

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Anyone hear that bell...?! School's in:

When you get a tune it says premium fuel only and this is why because there IS a difference. It burns better, cleaner or something and I'm sold on the better gas now.
Why does the cheap fuel cause knock and what is it they put in it that does it?...
After that tank was done i filled up with my normal 92 premium from the BP near the airport i usually go to and i instantly felt the difference
I hate to say it, but, check the Top Tier list; BP hasn't been rated for good gas in a while!

As far as why cheap gas 'knocks', strap in for the answer: because heptane is cheap as shi*.


"Antiknock Quality
An octane number or rating was developed by the
petroleum industry so the antiknock quality of a gasoline
could be rated. The octane number is a measure
of the fuel’s tendency not to experience detonation in
the engine. The higher the octane rating, the less the
engine has of a tendency to knock.
Two methods are used for determining the octane
number of gasoline: the motor octane number
(MON) method and the research octane number
(RON) method. Both use a laboratory single-cylinder
engine equipped with a variable head and knock
meter to measure knock intensity. A test sample of
the fuel is used in the engine as the engine’s compression
ratio and air-fuel mixture are adjusted to develop
a specific knock intensity. There are two primary
standard reference fuels: isooctane and heptane. Isooctane
does not knock in an engine but is not used in
gasoline because of its expense. Heptane knocks
severely in an engine. Isooctane has an octane number
of 100. Heptane has an octane number of zero.

A fuel of unknown octane value is run in the test
engine equipped with a variable compression cylinder
head and a knock meter. The severity of knock is
measured. Various proportions of isooctane and
heptane are run in the engine to duplicate the severity
of the engine knock when the test fuel was run.
When the knock caused by the isooctane and heptane
mixture matches that caused by the fuel being
tested, the octane number is established by the percentage
of isooctane in the mixture. For example, if
85% isooctane and 15% heptane produced the same
knock severity as the tested fuel, that fuel would be
rated as having an octane rating of 85."
 

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So, just for ha-ha's, I tried a tank of 93 octane in my SE 5-speed. I must admit there is a difference in the performance of the car, mostly in the ability to keep it in higher gears at lower speeds (which I assume is the knock sensor not triggering). I would surmise that this would result in slightly better gas mileage if driven accordingly. Having said that, probably not worth a $.30 or $.35 differential.
 

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So, just for ha-ha's, I tried a tank of 93 octane in my SE 5-speed. I must admit there is a difference in the performance of the car, mostly in the ability to keep it in higher gears at lower speeds (which I assume is the knock sensor not triggering). I would surmise that this would result in slightly better gas mileage if driven accordingly. Having said that, probably not worth a $.30 or $.35 differential.
Noticed pretty much the same thing. Decided to try it after putting some really bad regular in my car (station usually carries good gas, but apparently not this time).

It's for sure not going to be worth the extra money for the better gas mileage (I have been harder on it than usual and it's gotten the same 30-31 mpg mixed) but I'll throw it in the tank every once in a while. Especially if I get anymore bad gas.
 

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I use premium and have been since my first fill up with my car. Premium where I get gas is ALWAYS exactly 10cents over regular grade. and mid grade is 1 cent more than regular. I don't know what a difference regular would make in my car since I haven't put any in so can't comment on any differences.
 

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20 cents for premium is well worth it to me

I just switched to premium and the difference is noticeable.

The low speed stumble/bog is reduced, full throttle acceleration doesn't surge nearly as much, and on the freeway, part throttle response is improved, and the PowerShift doesn't hunt gears as often.

Keep in mind though, here in California our regular is 87, and premium only 91 (AKI), so our premium is more like mid grade elsewhere.


Another point...

I haven't driven enough since switching, but I wouldn't be surprised if my MPG is improved.

Now that gas is $4.27 for regular here, the additional .20 is a smaller percentage of the total, and takes less additional MPG to cover the cost of premium.
 

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Ive been switching between unleaded and premium ethanol free since I got my car. I would say the premium adds a little more pep but overall the 30cent difference isnt enough to make me run it every fill up.
 
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