Is there such a thing as over reving the motor while in nuetral? Can you damage anything?

 

Yes, Yes

 

Rev limiter will protect the engine from an over-rev in neutral and up shifting.

It just won't protect from over-rev when downshifting, e.g. from 5th to 2d accidently, when you meant to grab 4th.

Ranger

 

This is similar to a debate my Father and I have been having. Does it matter whether or not the engine is under load when at high, but sub-limiter, RPMs. Ex. staged at the tree with RPM pegged at 6,000 or above. He says high RPMs in nuetral are harder on an engine that when under load. I claim it doesn't matter, but neither of us are by no means experts.

 

The Z06 engine is stout. Many racers are holding 6K+ launch rpms with no issue.

I think there is a bit of difference between HOLDING a 6K+ launch rpm and, say, REPEATED HAMMERING of the throttle between 4000-6500 in neutral. The no-load acceleration and then deceleration of the valve train certainly puts it under stress. Whether that will lead to breakage is another question.

Ranger

 

I think the only real difference is that when launching, you bring up the rpms slowly and hold. If you just hammer it while in neutral, the rev limiter won't stop the inertia from taking it to about 7500rpm where you can definitely do some damage.

 

So what kind of damage could occur if one was to rev up while in nuetral and say hit 7500 RPM's??

 

Think about that again.

If you listen to the engine of a racer launching "off the limiter," you will hear the engine popping as it occilates between 6600 (where the rev-limiter cuts fuel) and 6599 (where fuel is turned back on).

The popping noise reflects the action of the limiter, which definitely protects the engine from over-rev in neutral. If it didn't, launching "off the limiter" could not occur.

Ranger

 

Listen to your father! He's a wise man. (no he didn't pay me to say that).
As Ranger said (and one look at his time slips puts him High on the "credibility list") the LS6 is tough, no doubt about it...so this "argument" is one of "degree."...with "-er" being the key point of "harder".

Moving parts in an engine are all "loose"...they "rattle"...otherwise they couldn't move...when you rev under load, each of those parts is stressed..pushing hard...crank is twisted...shaking forces try to rattle all those parts, but the preload in them, due to them already being under load the instant before, helps damp out that energy. In addition, because it's under load, those slinging pieces cannot accelerate as fast as when they are unloaded (engine in neutral can change RPMs MUCH faster than when "loaded")...and that acceleration = much higher shaking forces (Jxy, Jxz for u rocket-scientists)....so running high rpm in neutral is worse than when loaded, and accelerating RPMs harshly in neutral is much worse than when loaded.

Example?....consider grabbing a hammer, set the head on concrete and push down as hard as you can...then pick it up and look at the damage it did!...then lift it off the concrete a couple inches and smack it down with the same force as before...that was your connecting rod hitting your crank journal!