Just learned to brake launch my g37x sedan. I want to know if it can be damaging on the engine , tranny on the long term. People say it damages the torque converter, etc.

 

Yes - it does. Do it once a month, probably ok. Do it every week/day, probably going to break something. The 7AT doesn't exactly have a reputation for being..stout. So, asking it to do something it wasn't designed for is probably going to break it, sooner rather than later, if you abuse it.

 

Correct, you start diminishing the life of the TC over time especially after trans has warmed up. Your best bet to get the best of both worlds is to brake launch in wet conditions. Make sure you pay attention to your front driveshaft joints since these are a really important weak link. Engine damaging weak link.

 

I did it from time to time on my 07 with the 5AT. When I sold it with 120k miles, I would say the motor mounts could have used a refresh but otherwise no ill effects.

 

How severe are we talking here? I recently did a few 'brake launches' from the stoplight to measure my 0-60 and quarter mile. It wasn't heavy, I was up maybe a few hundred RPMS from idle and the tires didn't even squeal.

 

Should be fine honestly. Main thing I would worry about is the breakdown of fluid. Just service it in a timely manner and should be no ill effects. When I think 'launch' 2500+ RPMs comes to mind.

 

This.

I launch around 2500 or 3000 IIRC. It's hard because the wheels start turning lol.