ok heres the deal. on sunday i went to the drag strip and the fastest time i could pull of was a 16.4. that is freaking sad for my car cuz it was running consistent 16.2s last year.
it CAN be other things than just your exhaust..
last year i ran consistent 14.6's,14.7's, and 14.8's...
this year untill just last month the best i could manage was a 14.8 and consistent low 15's.....
the main bulk of the problem was a stretched timing chain. and the engine is just getting plain tired...
so i did a few things in the quest to regain and find more power.
chaged the rocker arms to 1.6:1 from 1.52,
bumped the compression ratio up to around 10.5-11:1.
put in a custom crank scraper,
windage tray,
reported the heads,
smoothed the complete whole runner in the lower intake manifold,
bored out my t/b from 56mm to 60mm.
added a bully stage 2 clutch,
Koni rear shocks (FIRM!

).
BFG KD tyres.
changed the muffler from a flowmaster 80 series running dual outlets to a single flowmaster 40 series.
changed the timing chain as it was so stretched you could pull it off the cam gear.
added in a EP LSD.
and the result... 14.59..... all that work.... from last years 14.64 to this years best of 14.59 --track conditions were bad. about 0-5 degree's that day. not ideal for hooking up.
there are days you go to the track and you just dont run right. thats the way it is.
i know so many guys that i go to the track with that run good times one weekend, the next they cant pull off anything close again.
.2 seconds is fairly close for a different track day... its hard to say "track conditions were exactly the same" as they are hardly that. was the pavement the same exact temp? what way was the wind moving.? what was the exact humidity?. was the air temp exactly the same...
if you start now always running 16.4's then yes you could have maybe a problem. but one track day does not entirely point to a problem.
not saying you dont have a problem somewhere. it COULD be your exhaust setup... maybe maybe not?
it could be your engine getting tired out.... maybe?
it sucks when you run a time and then all of a sudden you cant run the same times... i know the feeling all to well..