QUOTE(dares @ Feb 16 2015, 10:43 AM)
kasi bikin time limit...10 secs max in 9k only when under certain engine temp

too many things to worry..
valve spring can return in time ?
9000 rpm = 150 rotation per second
effectively .. one piston do all 4 stroke within 1 seconds for 75 times..
inlet valve open during intake and close during compression.. 1/4 of each cycle.. 1 / 75 / 4 = 3.3 ms ... (the valve have to return to its original position)
ELSE you will successfully married the piston to the valve ... (the engine aint cheap)
are the engine internal balanced nicely ?
4B11T unlike the previous 4G63T .. are alluminium based... and to make it better performance.. there is no balancer shaft build in.. the engine are factory tested good for 7500 rpm ... (vibration within acceptable range) .. introducing a 9k rpm .. im not sure will it self distruct .. lolz