Up to a point i don't blame VW limiting the revs of their engines in neutral...my 19 year old petrol MB will only rev to about 3500 in neutral so its not just VW...the Diesel MOT test running the engine up to governed maximum has resulted in broken cam belts and ruined engines.

The test is unfit anyway, how come Mundanos managed to pass the test ok but if you were unfortunate enough to be behind one on full boost you'd be smoked out.

I first qualified as an MOT tester in 1985, and the diesel smoke test was introduced some time after that. I always felt that the test was flawed, and that it was totally unnecessary to rev the engine right up to its limit. The vehicle would never be driven in such a way, and so why the need to test it that way? It was well documented at the time that certain procedures must be followed, and that we must be aware that engine damage could occur. Everyone knows, or at least should do, that you should not rev any engine up to its limit without any load on it. Many modern cars are set so that it can't be done, and just as well too.

Full throttle, max revs under load at the limiter is not a problem with a well maintained engine.

Full throttle, max revs no load at the limiter can cause problems and these problems can be very expensive. The fact the engine revs up and slows down much faster than it ever would on the road has been known to snap cam belts especially those past their sell by date.

That is why there is a huge disclaimer from the DVLA and the garage on the wall.

Cameron's and co have introduced infrared scanners that read emissions from individual vehicles and fine them via the ANPR cameras linked to the DVLA DATA BASE

Do you have any evidence to support that statement ?

Edited by RobJP on 20/03/2016 at 18:22