Overhead readings are usually not that accurate. Best to take a hand calculated rating forreal mpg rating.

 

In general, our overhead unit is about 1.3-1.7 mpg higher than actual calculations of gallons used and miles driven. It seems to be closer on highway runs than in town runs. On our trip to Rapid City the highway mileage on the overhead was within about .5 - 1.0 mpg of the acutal mileage

 

What is the correct way to do that?

 

Fill up your tank till it's full, not the first click, but till it's full. Zero your trip meter in the guages.(Little button on the left inside the cluster) Drive till you get an empty tank. Re-Fill the tank to the same full as you filled it the last time, not the first click, but till it's full. Record your milage from your trip meter, record your gallons from the pump. Then take the milage traveled and divide it by the fuel consumed. Woila! Hand calculated reading!

Hope this helps!
Al

 

Al. This is very helpful. Thanks alot. It is what I thought I was supposed to do. Just filled up and zeroed the trip odometer last night. $89 US. OUCH!!!

 

take a look a the water4gas thread I am looking into doing this myself on my own chrysler.

 

$89... WOW! lol I fill up the Aspen at the grocery stores' gas station, I get 7cents a liter off, I pick the maximum of $100 preauthorized fill, to fill it, and the gauge shows full when done, but not full. Really a pain if I want to check milage, and If I want to fill my Ram diesel, then I have to do two preauthorized fills to fill my tank. Even more of a pain.

 

My dad was asking today about this. I haven't had a chance to do any reading on it as of yet. Thanks for the info! Gota link?

 

http://www.h2opowersystems.net/index.html

hemi 300 in a video on here

 

THANKS FOR THE INFO. HERE IS A DIRECT LINK TO WHAT CHRYSLER TECH IS TALKING ABOUT.

www.mileagebonus.com

SOUNDS INTERESTING. BUT IF IT IS THAT EASY THAN WHY ARE CAR MANUFACTURER'S STILL MAKING ENGINES THE CONVENTIONAL WAY? DOES IT REALLY WORK? WILL IT CANCEL YOUR WARRANTY WITH CHRYSLER IF YOU PUT THIS ON YOUR VEHICLE? LOTS OF QUESTIONS HERE. I AM A SKEPTIC.