Cats Or No Cats

Jul 13, 2017
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i have been debating about an X pipe with or without cats for sometime now. I have read some reviews that some Mustangs with slight built motors have destroyed high flow cats. Some claim the insides have been blown out. Is this a real concern? The only reason I am considering cats with the X pipe is because of the smell issue I keep hearing. I know my wife would complain if it smelled bad. I have a 2004 GT slightly built. Any opinions out there on this issue of the inside of cats blowing out?
 
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700HP Hellcats are running through catalytic converters. I don't believe a lightly-built 4.6 should threaten a catalytic converter unless they're dumping so much fuel the cats overheat, go cherry red and blow their guts.

Get the tune right and they should be fine.
 
I'm going to get a catted x pipe when I get long tubes on my 04 GT. You certainly won't blow them out with a 2v. I've had both off road and catted. Catted on a 2v or 3v give in my option plenty of sound and aggressive tone all while allowing you to pass inspection without changing back to a stock or catted pipe. However, an off road is substantially cheaper.
 
I went back and forth with the same decision and in the end didn't want to have to constantly swap out an off road for emissions testing. I went with the Magnaflow Catted Tru-X and I love it. I had the factory H and then the MRT catted H all paired with my same Steeda cat back. The Magnaflow has the best tone, volume, power (or at least throttle response) and I have no smell issues and have passed CT emissions. I highly recommend it!
 
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Before you get a midpipe you should consider:
1) do you want long tube headers? (if you do then maybe you should wait so that you save money by doing the swap all at once and you match the header/midpipe combo perfectly)
2) do you want a x-pipe, h-pipe, or a prochamber? (Go listen to tons of videos of different catback/ midpipe/ header combos)- they will all perform- it just comes down to sound preference)
example: (MAC ceramic long tubes, stainless steel MAC prochamber with SLP cats, borla stinger catback)

View: https://youtu.be/KpyVBV5R9tw

The above combo sounds like this when driving:

View: https://youtu.be/uMx4I-MRWko


3) buy stainless steel. The aluminized stuff is cheaper but won't last as long.

There are tons of opinions on brands. I wouldn't blacklist a brand but the general trend I have always found is you get what you pay for.

Good place to look and hear exhaust notes:
https://www.americanmuscle.com/99-04-mustang-exhaust.html
 
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What are the opinions about x pipes from pypes, slp and bbk? I would like to get the Magnaflow but they are pricey.

I agree they are pricey and I have never tried any of the brands that you mentioned, but reading online I decided to just wait til I could get the one I really wanted, not the least expensive immediately, and I have no regrets- the Magnaflow is worth the money. On top of everything I already stated above, it also fit perfectly!
 
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I just bought the bassani catted x pipe and just put it on yesterday. You can run it with or without cats, I'm running it with cats right now and am completely satisfied. Super loud with my borla stingers, I can tell that there is a good increase in power too. No cats can sound really good but so can running with cats. And plus it's the legal way and it's better for the environment.
 
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i have been debating about an X pipe with or without cats for sometime now. I have read some reviews that some Mustangs with slight built motors have destroyed high flow cats. Some claim the insides have been blown out. Is this a real concern? The only reason I am considering cats with the X pipe is because of the smell issue I keep hearing. I know my wife would complain if it smelled bad. I have a 2004 GT slightly built. Any opinions out there on this issue of the inside of cats blowing out?
I have had H Pipe w/o CATS, X Pipe w/CATS. The X Pipe w/CATS flowed just fine w/o power loss. Recently pounded nail in the coffin of my Cats when we did a computer tune after an Eaton upgrade to my 2001 Cobra motor. They were 10 years old anyway. Found a rural exhaust guy who cut them out and welded in connector pipe. Car can get loud when I push it! Have the Flowmasters (2 1/2") w/3' tips now. It is quite fun!
 
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I have had H Pipe w/o CATS, X Pipe w/CATS. The X Pipe w/CATS flowed just fine w/o power loss. Recently pounded nail in the coffin of my Cats when we did a computer tune after an Eaton upgrade to my 2001 Cobra motor. They were 10 years old anyway. Found a rural exhaust guy who cut them out and welded in connector pipe. Car can get loud when I push it! Have the Flowmasters (2 1/2") w/3' tips now. It is quite fun!
Do you recommend the cats or run without them? How is the smell without the cats?
 
Do you recommend the cats or run without them? How is the smell without the cats?
I would run with cats. And if you decide to add forced induction or nitrous, and start taking it to the track to get your best time, then I would run without cats. I recommend the bassani X pipe w/ cats because it comes with cat delete pipes and you can go back and forth without welding.