Thanks for your reply mate
When would you start causing harm, when you keep it at around 6k for a prolonged period? What about revving it past the red line but not holding it there?
I've always thought it was bad due to the lack of airflow. Also heard it's hard on the gearbox/clutch?
On the other hand I've heard it's good to rev it up whilst idling to blow out the carbon particles etc clogging the system when it's not been thrashed for a while.
Gearbox and clutch won't be engaged so won't be moving and there's no load on the engine so very little to go pop, especially with the rev limiter in play.
Blowing out the particles sounds like a myth to me, there's no real science behind that at all that I can see. A good ol' fashioned Italian tune up can help sometimes, but not just revving in neutral.
As far as holding the car at the limiter goes, whilst I wouldn't do it personally that's pretty much how they test engines to destruction. I'd be amazed if Nissan didn't do just that to the V6 in the Zed for days on end.
I've seen someones engine go pop from revving it. Was a chav at Santa Pod a few years ago. It was hillarious