Lil Wayne -- Rips Birdman With New Song ... I Saved Your Ass, But Now I'm Gone!

Lil Wayne just opened a lyrical can of whoop ass on Birdman by releasing a mixtape with tracks that take direct aim at his former mentor and Cash Money Records.

Wayne dropped "Sorry 4 The Wait 2" -- a clear reference to his long delayed "Carter V" album -- and goes right in on Birdman with a song called, "Coco."

Some of the lyrics include:
"Who kept this s**t together? N***a, me, that's who!
Who was there when n***as left? N***a, me that's who!"
Cash Money is an army, I'm a one man army!"

He also raps about going out like Tony Montana in "Scarface."

This should put an end to any doubts ... the Wayne-Birdman beef is 100% real.

The timing of the song and mixtape are interesting ... considering internet rumblings that Wayne could be plotting a move over to Master P's No Limit records.