Hi,
I need to disable the collision of a prop_phys at runtime.
disableDraw is nice but it just make it invisible and still solid.
other ways that I'm not aware of?

Why would you want to disable the collisions of a physics prop? The point of prop_physics is that it can fall and move and bump into things. Use a prop_dynamic if you don't want it to be physically simulated.

There are a few ways that I wouldn't recommend, but here they are:
Please don't use
You could temporarily parent it to something static like an info_target, or set the Debris spawnflag to make it ignore the player.

I need to disable the simulation for a second, then it can continue to behave like a prop_phys is meant to be.

setting the spawnflag seems very promising. i'll test with that and report.
thanks

changing the spawnflag doesnt work at runtime
ent_fire entity addoutput "spawnflags 260"

If there's a specific wall you want your cube to phase through, just make that wall a func_brush to give it a name and set up a logic_collision_pair with Attachment 1 being your object and Attachment 2 being the brush. Now you can turn collisions on and off on a whim and not affect anything else by simply telling the logic_collision_pair to DisableCollisions or EnableCollisions.

the "wall" is the player...

So use !player as one of the entities.