anyone using premium gas ?

[KaputtEqu1pment]

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.

[Rememo]

I'm not getting into this whole octane argument. It has been going on since the dawn of the internet and I'm sick to death of it, but here is a great site for locating ethanol free fuel:

http://pure-gas.org/index.jsp

[Mile30]

Originally Posted by YoteMobile

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

[Mile30]

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

Originally Posted by BowerR64

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."

[DAC17]

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.

[Bwill9886]

Originally Posted by DAC17

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.

[Ox-y-GenIII]

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.

[r1derbike]

Gas has risen 40 cents a gallon here in a week. Use cheap regular, and no unnecessary trips.

This is going to get ugly, I'm afraid.

[SpinKix]

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.

[-sokO]

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.