High performance Japanese and German cars have a 280ps power limit and 155mph speed limiter respectively. These limits seem to be described as “Gentleman’s agreements,” in magazines I have read. Where did they originate and is there any legal reason for them to have them.
Some years ago there was a movement to have the German government put speed limits on the autobahn, but this was meeting a lot of resistence from drivers. The car manufacturers took the pre-emptive strike of installing (155mph) speed limiters on their cars afterwhich this movement lost steam. The car manufacters also had a valid point that the tires they put on the cars are not rated past this speed and could fail if driven faster than this on a continuous basis. In fact, the speed limiter is set lower than 155mph when tires with a lower speed rating are fitted. Apparently, individual car owners can have this speed limiter disabled without incuring any penalty from the government if they can find a mechanic to do it for them.
I don’t know what the story is in Japan but surmise the power restriction is an attempt to save fuel.