Speedometer Question
 

After constantly being passed on the highway by minivans and dump trucks I thought it was time to test my speedometer. My wife and I drove side by side and we found when the Boxster said 70 MPH, the other vehicle said 64 MPH. Has anyone else ever experienced this problem and/or is this a typical problem with Porsche?

I have only owned the car for about a month and absolutely love it! However, when I feel the need for speed (as is often the case), I would like to accurately know how fast I am going.

My speedo is 4 mph fast so at 64 mph on my speedo im going 60mph. This was confirmed with radar. No not a ticket issue.

joshuaalbert, how do you know your wife's car is accurate?

Mine is 3 MPH fast, which is the normal factory setting. Your dealership can dial this in to be more accurate.

The factory setting comes out to about 3-4mph fast. When I plugged in a OBDII reader and watched the readings, I was going 4mph at idle sitting in the garage so Porsches don't just "look" fast when they're sitting still. :cheers:

Mine is about 4 MPH slow according to the CHP radar trailer. :confused:

So someone spell this out for me. If I've got the cruise set at 65 in a 65 mph zone and a cop shoots his radar at me, am I really going 4 mph over the limit or what?

If your speedo is 4 MPH SLOW and it says you are at 65 then you are realy at 69 MPH. So he or she could give you a ticket no matter what your speedo says. Sucks huh!

Hi,

Porsche uses what they call a Safety Factor, indicating usually 3-5 miles faster than actual speed. For pre-2000 models, you can retrieve actual speed in KPH from the diagnostic function of your Climate Control Display, along with many other data points...

Happy Motoring!... Jim'99

I frequently drive my wife's '04 past a CHP radar indicator. When the radar says I am going 65mph the spedo says I am going 68.

Borrow or buy a handheld GPS. 100 bucks or so, very accurate speed. My 06 indicates about 2mph faster than actual according to the GPS. Both my Toyotas are about the same.

Make sure you have the correct tire and rim size on the car. That could be your issue IF it is the Box that is incorrect.

Insatiable
 

My ,03 was radared @ 110kph and speedo showed exactly115
Cheers, Glenn