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I got the focus so i wouldn't have to use premium. [histerical]
 

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Not worth it if you are looking to improve your mpg, but it is worth if you use it from time to time to "clean" the injection system (injectors, valves, combustion chamber, etc).
I say this because I used it twice and the result in mpg was not better than what I had with regular. I will use it from time to time though (for maintenance purpose).
 

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I use premium because it says right in the manual "premium fuel will provide improved performance" (pg. 354 (2nd printing)). Plus my station two blocks away from home has ethanol free premium.
 

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I have gone back and forth between grades (3 tanks reg, 3 tanks premium, s tanks reg, etc) and have actually noticed a mileage difference with the premium. Not huge by any means, 1-1.5 L/100km, but still a difference. I think that works out to 2-3 us mpg roughly.
 

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I use to think that gas was just gas but not any more. Now that i know more about it and how it works it makes sense and now i get it.

I use to get quick trip gas because i thought since it gets more buisness it would have the fresh fuel but after a few data logs ive decided im not going buy from them any more. I tried a tone of different fuels and finally found a fuel my car likes and ive been running it for a few months now.

This is what bad gas looks


And this is what the gas im using now looks like


With bad gas you rknock sensor detects knock and retards your timming. Good gas you can really wind the timming up with no knock and it improves performance.

IMO its worth the extra money. You can do your own testing but ill bet you will come to the same conclusion. You may not really feel it but you can see with the datalogging what it is actually doing.
 

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I'll pay the .06 extra for the 100% pure stuff. I spent the last 5yrs feeding my 06 Charger R/T premium fuel. Never again if I don't haft to.
 

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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.
 

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Its true in a way, stock the car is "tuned" to run that gas. I believe they retard the timming to allow the cheap fuel to run ok in it.

You start to tweak it with a tune and you bump the timming way up and then the cheap gas starts to cause knock and then the car backs off the timming like in the pictures i posted.

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 im sold on the better gas now.

Why does the cheap fuel cause knock and what is it they put in it that does it? i dont know but i like my car so im not going to put junk in it if there is better stuff right next to it.

A few weeks ago i went to a cheap mom and pop gas station and i filled up with their premium because i was about out and knew i couldnt make it to my regular station. I swear i thought something was wrong with my car. It lost some of its zip i wasnt sure what was wrong it didnt run rough or anything it just didnt have the same zip it did.

After that tank was done i filled up with my normal 92 premium from the BP near the airport i usualy go to and i instantly felt the difference.

If i ever get in a pinch again with fuel im using just what i need to get back to the regular station and thats it.

Their premium must be low grade or something it just wasnt right.

I even had Tom tell me once after i posted a datalog and he asked me what fuel i was using because it was junk and it wasnt the same stuff i posted in an earlier log he adjust the tune to. This was early before i found a good fuel my car was happy with. The junk fuel was from quick trip at that time.
 

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I started a thread about this a while ago that turned into a war, the general feeling for those that used it is YES it makes a difference in the 2012. It says so in the manual that premium gas will result in better performance. I get 4-5mpg better while running premium than I do on regular. Plus since the tank in the Focus is so small, even a 30 cent price difference is only a few extra bucks, worth it just for the extra cleaners they put in the premium gas too. (All IMO, feel free to say I'm a stupid kid who loves giving their money to oil company's)
 

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I run premium fuel and I do get better mileage with it, but since it costs more it ends up cancelling the savings out. I feel like the car runs better with 93 octane in the tank opposed to 87. I also find Shell to have the highest quality fuel in my area so I stick with them as much as I can.
 

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I've run premium since the beginning so I can't do a comparison. But I've had no knocking or shudder or any other problem reported here so I'll stick with premium. I figure this is a 12:1 compression engine that's gonna like the anti-knock compounds in higher octane gas. And the manual says as much. With 2500 miles on the clock I'm getting about 36 MPG in 90:10 highway-city driving, flat roads, low traffic, 60 to 65 depending on conditions.
 

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I use to think that gas was just gas but not any more. Now that i know more about it and how it works it makes sense and now i get it.

I use to get quick trip gas because i thought since it gets more buisness it would have the fresh fuel but after a few data logs ive decided im not going buy from them any more. I tried a tone of different fuels and finally found a fuel my car likes and ive been running it for a few months now.

This is what bad gas looks


And this is what the gas im using now looks like


With bad gas you rknock sensor detects knock and retards your timming. Good gas you can really wind the timming up with no knock and it improves performance.

IMO its worth the extra money. You can do your own testing but ill bet you will come to the same conclusion. You may not really feel it but you can see with the datalogging what it is actually doing.
Not to rag on you but your datalog is inaccurate to say the least.

Gotta do a log from start up to 55mph cruise and take a time stamp from both at the same time stamp.

One log has idle load and another log has driving load. Knock is almost always retarded slightly under normal driving load.

Even though the logs are cool that you posted it would make a difference to have a 55mph time stamp on both logs to see the difference. That way same Load same intake air temps same everything except for the gas.

But I will say this. Good quality 87 will beat a poor quality 91-93 all day.

Now a good 91-93 will also be better then a good quality 87. Is it worth .20 cents more for the small bit of performance your factory tuned car will get..

Simple answer... No

But this is coming from someone that needs premium in 2 of my 3 cars lol.
 
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Well i dont care to change peoples opinion really. I feel and with the SCT and the datalogs i can see the results. Anyone can do it themself, i dont really care to run a lower grade fuel to prove what i believe any more.

I know the logs arnt identical but i was pointing out that the engine has a knock sensor and if that sensor detects engine knock it will retard the timming which will lower performance. If lower grade fuel causes knock and retard timming how can it be better to use that fuel?

Even if its a slight improvement in performance IMO every little bit helps with this car.

I paid $200. for a CAI that had little improvement, $400. on a new header and exhaust with little improvement and then $420. for yet again little improvement. After all that i maybe gained 5-10hp so IMO the gain i notice with the premium isnt much compaired to what ive already put into the mods.

If i can feel the difference thats worth it to me.
 

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I use premium because it says right in the manual "premium fuel will provide improved performance" (pg. 354 (2nd printing)). Plus my station two blocks away from home has ethanol free premium.
If you read the whole paragraph its talking about the fact that in some regions regular is 85 octane and that using premium will give better performance than 85. It does not say you will get better performance than 87 octane.
 

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One problem with Premium around here lately is the price.
Like Regular is $3.07 But mid level was $3.24 and Premium was $3.41
I do not know why the others are so much more.. Or is is like a 'sale'? on Regular.
But with that much increase.. i stick to Regular.
I do try to keep what is in the tank a little over Regular with a partial fillup of Premium every third partial fill.
(I usually fill it at 7 gallons or so)
Shell or Mobil gas only.
 

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I usually fill mine with regular from the local Husky/Mohawk. 87 octane and consistent quality fuel. Where as the other station's in town the quality seems too vary greatly depending on the tanker load.

I have had some fillup's when I've used the other stations and the engine will be all over the place severe bogging car deciding too go rev. happy, etc.

Imho, this car is more touchy about needing good quality fuel than most.

Also little known fact but one of the pollutants the cat is designed too remove is N2O or Di-nitrogen oxide so shell enriching their fuel with nitrogen leaves more available nitrogen too form the compound because nitrogen does not burn so it actually makes your cat work harder.

As for their claims of reducing carbon build up your engine shouldn't be seeing too much significant carbon build up unless it's running rich. So benefit's for a DD are pretty negligible. But it does offer some frightening disadvantages.

Replacing a cat can cost oh $3000.00 or more which is kind of ouch inducing.
 
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