Prochamber with cats? Does it exist??

astronut1885

Founding Member
Jan 31, 2002
1,899
4
39
Assonet, MA
Hey guys. I had an o/r prochamber and flowpath catback on my 87, and it was the sexiest thing I ever heard. Now I have an 04, and I would love to put a prochamber on it, but I want to stay emissions legal and a little quieter this time around. I've looked, but I can't find a catted prochamber. Are they out there, or am I either stuck with an X or an o/r prochamber? Info would be great!
 
Ok, so, new question: If I were to install one of these, with stock style shorty headers, do I need MIL eliminators or 02 sensor extensions? Or is this a direct bolt-in for my '04? I searched, seems most people are talking about this with an o/r prochamber. I'm determined to stay totally legal with this car, and the noise reduction with cats over my old o/r model on my 302 is nice seeing as cops in my town are total douchebags... I still love the sound of a prochamber, I just don't want to rattle my neighbor's house anymore. :nonono:
 
I'd imagine that if it has cats, it's designed to be emissions friendly and you wouldn't need MIL Eliminators. I know Magnaflow's catted midpipes say they're emissions legal but I'd check with MAC just to be sure since the product description doesn't say anything about it.
 
I'm still a 4.6 newbie. I'm guessing the rear 02s are downstream from the cats, and thereby are there to make sure the cats are doing their job. With an O/R pipe, they're not there and aren't filtering, so the rear 02s must register major issues with the computer. The MIL eliminator takes care of that I'm guessing. Now, with a catted aftermarket pipe, it should theoretically keep those sensors happy, although a higher flowrate of exhaust might still tick the little buggers off... Whatever happened to the days of straight pipes and carbeurators?? lol...
 
Ive got the catted mac prochamber on my mach, and yes you do need the extenders for the o2sensors. The guys at mac told me no but i found out the hard way. I wish i had gotten the cat-less prochamber because i think its still too quiet...even with single chamber flows.:mad:
 
Haha, your complaint is a blessing to me, I want the sound without the volume. I've had cops follow me home because they heard me coming in my 87. Quiet but nice is A-OK with me. Besides, I think I'll be backing it up with a SLP Loudmouth catback, so it'll be noisy...