Testing the top speed limiter on the M4

I know this is juvenile, but it had to be done.  I knew at some point, when I got some free space on the Autobahn, I wanted to validate the existence of a 155MPH top speed governor that plagues BMWs (even M cars).

Long story short – I reached 166MPH before it stopped accelerating. And, yes, it was still pulling hard to that point – there was no doubt it was limited.  I found this both exciting (because it was faster than 155), but also disappointing that it was obviously being retarded before it reached 180MPH or so which I would imagine is its theoretical top speed.

It crossed my mind that the limiter was an actual 155MPH because BMW speedometers notoriously read about 5MPH over at 75MPH.  Come to find out, that was a good assessment; there is still a 155mph limiter on today’s cars, but it is GPS based and not wheel speed or speedometer based.  166mph on the speedometer in this car on that day, actually was only 155mph.

Note that this was done legally (on an unrestricted part of the Autobahn) and safely (virtually no traffic).  Also, the picture was taken by the passenger; what a brave girl she is, I can assure you, she didn’t want to do this; yet she still took her eyes off the road to grab the picture.

Maybe because she didn’t want me to have to repeat the run. 😉