Exhaust Bbk Catted X-pipe Vs. Bbk Off Road X-pipe

Discussion in 'Fox 5.0 Mustang Tech' started by Straightjacketjacob, Jun 12, 2013.

  1. Sure this has been beat to death but I couldnt find it searching. I have BBK Long tubes into a BBK Catted X pipe on my car to pass emmisions. I had the BBK x pipe on it. Now it is much quieter. I made 370 HP out of my 347 at the rear wheels with the Off road X-pipe. They are running into 40 series flows. How much power are the Cats costing me? I plan on doing 2 passes with them swapping out and doing to passes with no cats. If im running the same times better to be green I guess. Car really does sound like crap and smells funny. Let me know if anyone has dynoed with these two setups.
  2. Well what does you butt-dyno tell you in terms of HP loss with cats? After all, that's what it's all about, right? But if #'s matter most to you I think you lost 5 hp per cat or 1,000,000 HP total loss to the wheels.:rlaugh: You should be feeling a tiny bit less HP on the top end. Also, your exhaust shouldn't sound like crap, just quieter and a lesser smell of gas when standing behind your car.

    Do you still have your thermactor system installed and functional?
  3. Cats can make about a 10 hp difference, which could be a tenth of a second at the track. Not a lot, but something. If you don't like the sound or smell without the cats, you should leave them on - the difference is not worth it. I had a 350Z for a while, modified the exhaust and couldn't stand the sound at certain rpm's. It cost me a lot of the enjoyment of the car.

  4. I think he's saying he doesn't like the smell and sound with the cats ON which to me doesn't make sense because I know both of my Fox's i've had that didn't have Cats both smelled like gas but sounded loud and great. With Cats on the sound is a bit quieter but still sounds pretty dang good and there should be NO funny or bad smells that's caused by Cats. Unless something else is wrong with the car is should smell "normal".
  5. Ok smell went away it must have been from them sitting around in a garage for years. Buy crap I meant much quieter than before. Power feels the same to me. It is almost to loud with the cats off. Maybe I'm just getting old. Either way I'm not going to the track in it. I was just woundering how much of a differance in power it really made.