Would this hurt the engine?
 

Would it hurt the engine if i rev the engine when its in the cold start stage like around 2k rpm?
Thanks

Nah, are you trying to blip the throttle to get rid of the cold start?

today i was making a sound clip of the rb exhaust and i didnt want to wait till the cold start was fully done. I reved it up to 6k rpm.

Well, it won't kill your motor, but it's not the greatest thing to do on anywhere near a consistent basis....

Ah, let the dude do what he wants. Then, when something breaks, he can troubleshoot it, fix it, and share it as a write-up on this forum.

Oil doesn't flow well when it's cold, so the lubrication wouldn't be as immediate as it should be. It isn't good for the engine, don't do it if you plan on keeping the engine for long. One time probably didn't hurt it, but don't make a habit of it.

Just don't rev more than 3000rpm when cold (thats what i do, some ppl here might say 4000rpm) and try to keep it without boost or low boost.