First I want to say that I know that upgrading the exhaust past the cat in these cars is normally not seen as something that will bring much benefit, but in my case it did.
I changed everything from the header outlet to the mufflers with 3" crush bent tubing and a 3" glass pack. 2.5 inch tubes at the stock mufflers inlet.
The gains were noticeable right away and I tested it at the track tonight. I dropped at least 3 tenths of a second on my best run compared to the last time I took it there, all KR is gone and running 20.5* of timing, I will probably drop to a 3.0 pulley soon. All this just by doing the exhaust upgrade.
The problem now is that I've got even less traction now. On the 2 first runs I spun the tires from 0 to 50.
first run:
me vs 2005ish stock mustang GT convertible auto trans.
GTP ET: 14.56
mustang ET: 15.57
second run:
me vs 300C SRT8 unknown mods (not sure if any)
GTP ET: 14.53
SRT8 ET: 14.07
that same srt8 was running 13.60s later on, he also had issues hooking up even though it's RWD.
my best run was a 14.27 when I finally got it to hook a little better, but still has room for improvement, it can probably run 14.00s with good traction. My best previous ETs where in the 14.60's with some KR and less traction issues lol.
Keep in mind this is at 5000ft high and i'm too tired now to make the conversions for you guys lol.
Sorry no trap speeds or 60ft. times are available either =(
