Okay we all know one shouldn't rev their engines into the red zone as this may cause damage. But something I'd like to know is what exactly causes damage? Are the RPMs just too high for the engine to be able to withstand?

 

valve float;valve springs cannot move the valve up fast enough,boom,valves hit the pistons.
damn i wrote valves 4 times

 

what u have a rev limiter of 7500 rpm? is it still dangerous to go in the red zone?

 

what is the red zone to you, what rpms?

 

actually, u wrote it 5 times

 

yep 5 times

 

i know the last one didnt count

 

hahah okay yeah there's lots of valves, we got that understood. So is that really the only cause of engine damage when over reving an engine past it's redline? Or is there anything else that occurs to cause some sort of irreversible damage?

 

This graph shows that at 8000rpms, a b16s pistons are accelerating at around 3500g's. That means that if the pistons weigh 1lb, then they "weigh" 3500lbs at 8000rpms. That's how much force the rod has to supply to the piston to accelerate it down from TDC.

You'll also see that the acceleration grows exponentially, so at 16000 rpms the piston would "weigh" 14000 lbs. Obviously ****'s gonna get ****ed up before then, as the rod is only designed to handle 3500lbs. The same goes for everything else that rotates. Also, the valves float because their "weight" increasees as they accelerate faster and faster, until the weight overcomes the springs and the valves jump off the cams....

Side note, I heard Ferrari uses or used controlled valve floating to their advantage, sort of like a vtec system, if you will. They called it ballistic something or other. That's pretty sketch if you ask me


[Modified by Lsos, 9:55 AM 12/18/2002]