In N. Ireland, new emission tests have been recently introduced. For diesel vehicles, these tests involve revving the vehicle up to its 'governed speed' and measuring emissions. These may involve doing this up to 6 times. For petrol vehicles, they are revved to 2500 rpm. Am I right in thinking that 'governed speed' means revving an engine flat out? There have been reports of engines being damaged during the MoT tests. Are diesel vehicles tested this way in GB (England, Scotland and Wales)? Can anyone explain the logic behind the different ways of testing a petrol and a diesel engine?