H pipe & flowmaster question.
 

Hi guys & thanks for any help you might give me. I like doing things myself, so i got the h-pipe & cats of a wrecked stang. I cleaned out the cats & installed the h pipe on my 2006, with a set of super 40's. this way i was able to keep my o2 sensors. but it absolutly killed the car, no low end & it seems alot slower. any ideas? stock 4.6 ,manual tranny, 3.55's. no engine code, just gutlees now. any help would be appreciated.

Gutless cats are the worse thing you can do since they kill power. If you want to run catless, you have to get an off-road pipe and even then, down low, you won't gain anything but may actually loose grunt.

The airflow gets killed because its a hollow chamber. You need to get a real off road H-pipe. Also any aftermarket pipe is going to have holes for the o2 sensors so you worries about that.