What is the "proper" RPM/PSI for a boost launch? What's considered the unsafe threshold? I'm just doing some research.
:lol:
There isn't a proper answer as each truck is different. Assuming yours is stock the method is standard however.
Put into N, apply brake, rev engine a little, brake presses a bit further (high vacuum and vacuum assist)
Allow RPM to decline to idle and put into D. Keep brakes applied and build boost for a few seconds. Depending on your pads you might make 5-10 psi (according to the gauge).
The Torque converter locks up at 2100 RPM in a stock truck so you'll probably start roling about then.
Things to be aware of: if you are standing there for too long with high RPM and not moving then your trans fluid is boiling.
DO NOT rev it in N and then immediately drop it into gear. Ask me how I know.
What mods are on your truck?
In summary there isn't a safe threshold. The more psi, the more power and your wheels spin or you go faster. Just worry about trashing the trans when you change gear or trashing the trans when the fluid boils.
HTH.
The unsafe threshhold is doing a boost launch to begin with. There is an unimaginable strain placed on every piece of the drivetrain when power is restrained via braking. Is it fun to experiance....yes, but always keep in mind that even a joy ride for a child on a carosel horse in front of Kroger's costs money.
You play and in time, you will pay (and it will be more than .50). Enjoy your boost launches.