Same here...many, many times. Like Ken said, there will always be some hope for snake oil. Maybe we can start with some fundamental lessons on the differences between alkanes and alkenes then move to some more advance hydrocarbon analysis? As I recall octane ratings and combustion stabilization was second year material.

I like your explanation

 

hrm... can we make it a smiley face then?

 

up here in canada, our premium has no ethanol added. ethanol will definatley give you worse mileage. i have never tried it, but have wanted to.

 

Save your money, premium gas will have no positve effect other than thining your wallet. Based on premium fuel characterisitcs it could cause negative effects on performance and mpg. The fuel and spark maps are written to optimize 87 octane. The only way to get any added benefit from above 87 octane is to use a chip or tuner, which rewrites the maps!

 

You guys sure make a big fuss about something thats not too hard to just test for yourself. I am not supporting putting higher octane fuel in a vehicle but I have tried it a couple times myself, back when my '99 was new, and I forget how much now but I did notice slightly better mpg but after doing a comparison with the added price it was still more expensive to burn the ultra. But I did get better mpg, then again it could have just been the earth rotating just right that day or something. So if anyone is really curious, just try the dang stuff, 1 tank of premium I dont think is going to do anything terrible to your motor or cats, unless the newer motors are a whole lot more fragile than my ol 4.2...

 

Try it why! There are many studies along with what has been said here! Advice by those who know the ECU maps real well! So no one is making a big fuss just informing those who don't know of why it does not work! Premium will not hurt cats or the engine, just cost you more with maybe less performance and mpg! Especially now at $4.20 per gallon which equates to $126 that is not worth while!

 

The difference in cost for a normal (for me) 20g fillup would be $4, since its a difference of 20 cents a gallon here... not quite $126.

 

Well most places the difference between premium and 87 is around 30 to 40 cents now.
For a fillup difference of $9 to $12. Want give it to the oil companies be my guest! It's your money, but I rather spend it on lunch than give it to Exxon to try and prove a point that will show exactly what has been stated.!

BTW these trucks hold 30 gallons! By just putting in 20 gallons you will be mixing with older fuel and your test is null and void. Because lower octane mixed with higher octane will net a few points higher then the lowest octane.

 

Why the attitude? If someone asks a question, and is willing to spend their $ to find the answer, then it is their business. All they said was that, if you wish, you can try the comparision yourself.............

 

Buck1 no attitude what he said was all the fuss, there is no fuss! Don't know where u are getting the attitude representation from???

 

It's amazing people that refuse to try premium and claim there is no difference. So how do you truly know there is no difference unless you try? You can point at any specs you want what so ever, but you'll never really know unless you try it. People used to believe the world was flat, until proven wrong. The difference may not be huge, may not make a difference to you, but it does to some people.

I run E85 in my '06 F150, but have experience using 87 vs 93 octane in my old '02 F150, '99 Explorer 5.0 & '99 Ranger 3.0. Sure there wasn't a huge difference in throttle response or mpg's, but it was noticable. No it didn't put out anymore hp/tq by just running 93. The motors did run smoother though.

So I agree that it may not be worth the added 20+ cents, but you can't discount the benefits, even if they are very minor.

 

I'm all for taking the experiment from the bench to the field but, in this case the chemistry, the mechanics and their interactions are so well known and studied that we can comment BEYOND THE SHADOW OF A DOUBT.

 

F-150 is programmed for 87 octane...E85 if FFV. You can waste your money on 91/92/93 octane if you wish. But you're not really gaining anything. The PCM is somewhat adaptive, but it can't make that drastic of a change without reprogramming. This means all the extra octane you are running will not be utilized.

My Mustang GT was tuned for 93 octane. It ran great and no problems idling. I ran 87/89 octane for 1 month (2 tanks) as a test to see if I could save a few bucks. Went from 17-18 mpg city to about 12-14 mpg city and about 22 mpg highway. Car ran like crap and didn't want to idle at lights...also had a noticeable lack of power.

Ran the tank until damn near empty and filled up with 93 again. Took about 100 miles, but the car regained all the lost performance and my MPG went back to 17-18 mpg.

 

E85 is on average 100-105 octane, while gasoline ranges from 85-93/94 octane even 100 octane if you get racing fuel. So are you saying that any 5.4L FFV isn't utilizing the entire 100-105 octane when you run E85, only the normal 87 octane it's rated for in gasoline form? The PCM is adaptable and must adjust itself when flipping from gasoline to E85, so why wouldn't/couldn't it take advantage of some of the octane difference? I know my FFV gets less mpgs on E85, but the engine runs smoother and throttle response is better and E85 is also currently $1.30 cheaper too. Sure it isn't a huge difference, just like 87 to 93 octance, but you do notice the difference when you switch back and forth.

Again the slightly smoother engine, slightly better throttle response and minor increase in mpg's when using 93 vs 87 may not be gaining anything to you, but it can play a factor into buying one over the other for some, no matter how insignificant the difference may be. Is it worth the 20 cents difference for 93 over 87, probably not to many of us but it is to some people. Just like some don't mind running 85 when it calls for 87, even though they get a little rougher engine and less mpgs. It's cheaper and that's all that matters to them.

 

Understand it's not a matter of a car "utilizing" the extra octane rating. Octane is a rating of resistance to combustion. The higher the octane the more resistance to combustion and the slower the combustion rate. Ethanol has a higher octane rating because it will not combust as readily and at the same rate as regular unleaded. Because of the higher octane rating the reaction needs more pressure (compression) to fully combust within a given interval. In a car engine that interval is dictated by the timing and the stroke.