I have been filling with at least 89 octane, like the manual says. I was just wondering what everyone else was using. Will a higher octane such as 93 result in better performance such as power, torque, fuel economy? Thanks in advance for the responses.

 

I use 87 most of the time and can't tell the difference. I would not recommend using higher octane than 89 more than on occasion to clean fuel injectors. The engine is tuned to use the 89 grade therefore your benefits will be minimal, if any. I've heard of people using higher octane and the results were not noticeable. Don't waste your money and possible do something harmful to your engine.

 

no advantage with a higher octane infact i used 87 in my 04 pac when i had it an got the same mil

 

In my Aspen, I seen a huge jump in fuel economy after using the recomended 89 Octane. The huge jump is an average of 1.2 mpg

Just thought I would comment, even tho I don't have a Pacifica.

 

I ran a tank of 87 in it a while back and noticed only 1mpg difference on the highway. Just curious, what's special in the motors that requires the 89? Most vehicles nowadays say to use a minimum of 87. Compression ratio?

 

yes compression ratio but most cars have knock sensors to adjust timing so the car will not ping

 

Using higher octane than called for is a waste of money and ultimately not good for the car. In the old days, you went with higher octane gas to prevent knocking in high compression engines. Knocking is caused by "pre-ignition" which means that under high compression, carbon deposits in the cylinder can get hot enough to start the ignition process before the spark fires. Higher octane gas is a little harder to ignite, and thus less prone to pre-ignition. Today's engines can determine whether there is knocking going on, and if so, adjust the spark timing to prevent it. Because higher octane gas is harder to ignite, it has a tendency to leave a little more carbon deposits in the engine, thus making the car a little more likely to suffer pre-ignition. The car can thus become a "high octane junkie", and begin to "need" the higher octane.

 

So is running 87 ok instead of 89 like the manual says? I definitely don't have extra money to burn. No pun intended...

Edit- I have been running 4 tanks of 89 and then a tank of 93, just to keep everything clean and to keep that Chrysler computer on it's toes, Ha Ha...

 

Pacifica3.82007 your post got me digging for my owners manual. I have an '07 Pac with the 4.0L, The manual says, "Your vehicle is designed to meet all emission regulations and provide satisfactory fuel economy and performance when using high quality unleaded gasoline having an octane range of 87 to 89 or higher. The manufacturer recommends the use of 89 octane for optimum performance."

In actual use we run 89 octane most of the time. In South Dakota 89 is 10% ethanol and is a few cents a gallon cheaper than regular 87. With our winters the alcohol prevents gasline freeze as well as cleaner burning BUT I can get 1.5 to 2 mpg better mileage with regular 87 octane. For those living in higher altitudes you will find regular is 85 octane. The Pac runs just fine on this also. Happy motoring.

 

I only run 89 octane and will continue to do so for the life of the vehicle; it's only 10 cents more