possible slow tc5 problem

[mobile chicane]

My tc5 has an lrp sphere in it with a 13.5 brushless novak with a sinterd rotor.

I have tried numerous gearing combinations but no matter what other 13.5 cars always out drag me on the straight, its not the batteries as I've tried several difrent lipo packs, I'm wondering if I need to put the gtb out of my b4 in there to get more oomph, do novak motors work better with novak speedos or am I barking up the wrong tree?