my zx5 is barking!!!!!!!

[1shnot]

I have a problem with my zx5...... zooming up and down the street to test out the new lrp system I've got, problem is when I gun the full throtle it barks...... I don't think it's my diff, since it does not slip.
next thing I've tried to make my slipper nut tighter, and I have made it tight and yet it still barks....
when I hold both rear tires down and pull the throtle it makes this barking noise until I give more throtle then tire breaks loose. what gives? I'm having same problem with my mf2 as well , no matter how tight my diffs and slippers are they still barks...... HELP!!!!!!!!!!

thanx guys