Gas Mileage

[mdillian3690]

Just curious when everyone one fills up there P-cars w/gas, what does the miles to empty read? When I purchased mine a few months ago it used to say somewhere over 400 miles now I am in the high 300's? I don't understand? Thanks!

[Scouser]

I take it you reset the computer each time you fill her up?

[mdillian3690]

Pretty much! Kind of anal isn't it?

[LVDell]

Mine is always in the high 200s (around 285). But then again I don't get more than about 250-260 to a tank of gas. Your OBC will start to program to your driving style over time.

[HenryV]

I have noticed that the OBC in our boxster (I think similar to 996), unlike in our other cars, does not average since the last reset, but always over the last 25 miles or so. So whatever your driving style has been in the past half an hour, that is what the OBC will take as your average, multiplied by the estimated remainder in the tank.

Your average mpg can vary from 16 mpg (about 272 miles DTE) to 25 (about 425 miles DTE) on a 17 gallon tank. Average is probably under 20 mpg (340 miles DTE), unless you drive hard.

In our other (non porsche) cars, the OBC number averages out between manual resets, and it tends to become very stable. In our boxster, the OBC number is always indicative of the driving style in the last half an hour or so, and it tends to fluctuate a lot more.

It is easy to check - without resetting the OBC, you'll notice that you get much better mileage on freeway driving than in city driving, within the first half an hour of the 'changed' driving style.

[ar38070]

Miles to go is a function of how hard you push the go pedal. You are driving harder/faster than when you first bought the car. If you want a dramatic demonstration take your car to the track. Miles to go plummets. Then when you take the car home Miles to go increases at least for a while. You "make" gas. :D

[jsoto]

MY03 C2 - My car show no miles when I fill up and I usually put in 15.5 gallans each time. I get around 23-25mpg on a tank of gas (or about 350miles - OBC)