When I first learned to drive, I was taught that it would destroy an automobile engine to rev it to red-line in neutral, although I have never know the basis of this claim or whether it is true. In the S, it is impossible to over rev the engine using the throttle because of the rev-limiter. If you warmed up the car appropriately and then placed the transmission in neutral, would it be any more harmful to rev the engine to the limiter than it would be to do the same thing in 1st , or any other gear? Is revving in neutral harmful, or is this a myth that has carried over from the days when there was no rev-limiter to protect from an over rev.

Thank you in advance

 

You're not getting any airflow in neutral which helps in keeping your coolant cool. Other than that, i don't see how it's different from you driving at 8 or 9000 rpms.

 

Your motor can handle it if you are up to operating temp, but i'm sure its not the best thing for the engine.

 

It's probably better to rev it with the clutch in so you're not spinning the transmission unnecessarily. Also, my grandfather who was an old school mechanic used to tell me that you could throw a piston through the head if the engine isn't under load, but I don't think that can be applied to modern engines.

 

This has been discussed many times in the past so I won't go into the details again.
A reciprocating engine works by the same principles whether it be an old one or a modern day one. Certain things just don't change.
Suffice it to say that there is a vast difference between revving an engine to redline with and without load. With load is what you do when you are driving the car down the road and increasing road speed as you rev. Without load is what this topic is all about - spinning the engine up to redline either in neutral or with the engine disconnected from the rest of the drivetrain (clutch in).
Although spinning it without load won't break and engine with a single event, it's still produces undue wear and tear on all kinds of parts (previously discussed). How many events will it take to do irreversable damage? You wanna try it with an engine that costs thousands of bucks to fix and/or replace? Go right ahead.
ps. It has nothing to do with over-revving. It has everything to do with spinning an engine at high speed with next to zero resistance.

 

In other words, don't do it unless you really need to for some reason (like staging at a race).