work on your launch, you should be able to get a 2.3 60ft time or better.. which will drop your 1/4 mile time IMENSLY.

with my zx2 (nearly stock) I pulled 2.34 60ft's and ended with a 15.7 but on a bad launch if the 60ft went up very little.. say to 2.4 my 1/4 time got way slower.. around 15.9-16.0

so you are either spinning bad off the line and don't know it.. or you aren't getting on it nearly hard enough and you got lots of traction left. my bet is on spinning.