Just filled up the tank with 91 octane premium fuel

[supmet]

I run 91 every once in a while, and it does feel smoother starting, accelerating, and idling.

Could it be a placebo affect? Maybe
Is it only a 2 dollar placebo, if it is? Yes


With the octane specific argument aside, aren't their cleaners and additives in 91 that aren't found in 87 at some gas stations??

[427chev]

Originally Posted by supmet

I run 91 every once in a while, and it does feel smoother starting, accelerating, and idling.

Could it be a placebo affect? Maybe
Is it only a 2 dollar placebo, if it is? Yes

Not only could it be, it is.

"CAR AND DRIVER" ran an article on this that included some objective testing of several vehicles. There was absolutely NO difference between regular and premium gasoline in vehicles that recommended regular (e.g. 87 octane).

There was a difference in vehicles that recommended premium, since running regular in them retards the spark and changes the engine mapping to the lower octane map.

[2009Toyotoad]

Originally Posted by supmet

I run 91 every once in a while, and it does feel smoother starting, accelerating, and idling.

Could it be a placebo affect? Maybe
Is it only a 2 dollar placebo, if it is? Yes


With the octane specific argument aside, aren't their cleaners and additives in 91 that aren't found in 87 at some gas stations??

Bingo! We have a winner. Big oil figured out a long time ago that to charge a premium price you need to create a positive preception that the vehicle "just seem to" run smother or more powerful when spending the extra $.10 to $.20 a gallon.

Some oil companies even figured out that they can package the stuff and give it fancy names like "Octane boost, Techron, or fuel system cleaner."

Now there is nothing wrong with buying or using these products. These products do clean the system of carbon crud. However, you can get almost the same effect from running WOT on 50 miles of back country road.

Since some of us don't have 50 miles of WOT roads nearby, these additives are a reasonable substitute.

Just don't fool yourself!