Weird Sound?

Ok, so im racing some guy right, hit about 80 n beat his ass. I turn into work n i start hearing this noise from under my hood area as i accelerate. The noise is only heard when accelerating n its kind of a flapping noise. i checked my front mudd flaps n their fine any clue wut else it could be? but besides that the car is running fine.

not good

yea its def not good, i just poped the hood while it was running looked like the engine was gonna pop out, think my motor mounts have had it. its a 99 z24 is this comin?