12 Second Club - What is happening...

I made a few 12 second runs a little while ago, but have not been able to get back into the 12's since. And from my trap speed, I think that I should be lower. What is wrong that I am not getting the times I want anymore?

I made these runs with a SLP Loud Mouth Exhaust System, SLP High Flow Air Box Lid, Free Ram Air Modification, and Nitto NT555R Drag Radials.

60' 1.947
1/4 12.839
MPH 108.99

60' 1.969
1/4 12.858
MPH 108.94

60' 1.975
1/4 12.866
MPH 109.03

60' 1.969
1/4 12.884
MPH 108.53

I know that one of my reasons is that my Nittos are bald as all hell, but I just got Pacesetter Long Tube Headers and a Pacesetter Off Road Y-Pipe on and ran it a week or two ago and came out with 13.0's at 108 and 109 MPH. I have seen multiple cars with many more modifications than mine with better times but the same trap speeds. A little help?

By the way, my car is automatic and I have been comparing to other automatic LS1 cars on the board. Thanks a lot.

Did you get the car retuned? If not, that's probably a big part of your problem. You could be running rich/lean, either will cause your problem. Tuning is very important, I've seen guys with bolt on cars add alot of power to their car with tuning, especially if you are getting knock retard or something. The tune in my car wasso messed that before it was tuned by eastside, the thing was barely at 300 hp to the tires because it was so lean. After they were done, the results are in my sig. You could have a similar situation going on.

tuning it everything....just look at me...i know im might be losing a little on my hp cause its runnin pretty lean (13.8-14.0) across the board...when it gets tuned it may gain or lose a few ponies....but it'll make a differance in drivebility for sure...hopefully ill squeak out a little more out of it though.