ITRCA

Hi
I was went to the track when I just had an intake and ran 14.8. After that I install a greddy sp2 full catback, now I running low 15's, wtf. Any help here?

how big's the exhaust piping...there's a lot of factors that can effect your time like temperature and inconsistent driving (from one time at the track to the next). My only other idea is that you're robbing your car of some backpressure that it needs, but I don't think that's the case.

Way way way too many factors to help you.
same drag strip?
same weight?
same weather?
same tires?
same air psi?
same phase of the moon?
same shoes?
Details man details!

As for the size fo the exhaust... I really doubt it made any kid of difference.

bbasso hit it on the head! I would also like to add...
Humidity?
Amount of gas in the tank?
Same type of fuel ie. grade/company?
If same track same lane?
Also same temperature of tires after burnout?
Same launch RPM to the "T"?
How many more miles on that same oil?
Also how many more miles on those same plugs/distr/wires?
Did you reset the ECU properly after exhaust install?

And my friend there are many more factors............

FWIW I ran 14.4 on a stock R in 80 degree weather in FL with the humidity about 75%. I took out all unnecessary weight as in the spare tire, jack, passenger seat. Also I had about a 1/4 tank of gas. I ran 2.2 60ft and trapped at 96 MPH launching around 5500