Do 1990 lx 5.0 with stock exhaust have 2 sets of cats? - Ford Mustang Forum
 
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post #1 of 11 (permalink) Old 03-22-2007 Thread Starter
 
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Do 1990 lx 5.0 with stock exhaust have 2 sets of cats?

Do 1990 lx 5.0 with stock exhaust have 2 sets of cats? i was lookin under there today and saw what looked like 2 sets of cats

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post #2 of 11 (permalink) Old 03-23-2007
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The Factory pipe has 4 Cats on it, 2 small pre cats and the 2 larger ones.

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post #3 of 11 (permalink) Old 03-23-2007
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Yep. Neat huh? Ever wonder why an X or H pipe are such a huge gain on these cars? They can't breathe.

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post #4 of 11 (permalink) Old 03-23-2007
 
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4 cats

Actually they only have 2 cats the first two that you think are cats are actually sound resonation chambers, that means they are just empty,hollow,chambers that are right behind your header collector. The other two in the tail section of the h-pipe,are cats. I only know this because i cut my h-pipe open and pulled the cats out. I was pretty surprised when i cut the first one open and it was empty.
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post #5 of 11 (permalink) Old 03-23-2007
 
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I always thought they were resonators too, but in my Ford Mustang Service manual they show them as Cats. Either way, when you install a new x-pipe with cats, there are only 2 cats.
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post #6 of 11 (permalink) Old 03-23-2007 Thread Starter
 
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im thinking about going with an h- pipe with long tube headers and not run cats(after i get it inspected) will it flow a lot better
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post #7 of 11 (permalink) Old 03-23-2007
 
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Quote:
Originally Posted by stangmoore View Post
Actually they only have 2 cats the first two that you think are cats are actually sound resonation chambers, that means they are just empty,hollow,chambers that are right behind your header collector. The other two in the tail section of the h-pipe,are cats. I only know this because i cut my h-pipe open and pulled the cats out. I was pretty surprised when i cut the first one open and it was empty.
According to this excerpt from The Official Mustang 5.0 Technical Reference & Performance Handbook referring to the 1986-93 exhaust system:
"This setup included . . . two light-off, or three-way, catalytic converters (referred to as TWCs); two inline, or conventional oxidation, catalytic converters (referred to as COCs) . . ."

I think someone gutted your first two cats to get some more power on the cheap or perhaps they were bad.
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post #8 of 11 (permalink) Old 03-23-2007
 
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Cats really don't restrict that much flow at all, if you ever looked through one, they look almost hollow. Cats get a bad rap because they're part of the emission system, which a lot of people think is horrible. In all reality, a properly working emission system on a stock Fox Mustang doesn't decrease horsepower. The problem is most people don't like weird looking parts under the hood, and when you go to modify your engien the emissions can then be a problem.

My car has all the working emssion system components on it, and I've installed headers, x-pipe w/cats, and cat back with a 3:73 rear gear and it runs great. Plus if emssion testing comes back I'll be okay.
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post #9 of 11 (permalink) Old 03-23-2007
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Quote:
Originally Posted by luniticlizard View Post
According to this excerpt from The Official Mustang 5.0 Technical Reference & Performance Handbook referring to the 1986-93 exhaust system:
"This setup included . . . two light-off, or three-way, catalytic converters (referred to as TWCs); two inline, or conventional oxidation, catalytic converters (referred to as COCs) . . ."
I think someone gutted your first two cats to get some more power on the cheap or perhaps they were bad.
Yep this is the correct info, someone must have gutted his 2 small ones.
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Quote:
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im thinking about going with an h- pipe with long tube headers and not run cats(after i get it inspected) will it flow a lot better
I have ran high flow cats on all my toys except the 65 that doesn't require them. They provide very little backpressure and alow the o2 sensors get to the correct temp to close the loop from start up. Dyno'd my old 86 with and without and only seen 5hp differnece at the wheels. Not enough to feel but definitely passed the sniffer without having to change in and out. Is it worth it? Only you can answer that.
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Quote:
Originally Posted by 90GT AOD View Post
Cats really don't restrict that much flow at all, if you ever looked through one, they look almost hollow. Cats get a bad rap because they're part of the emission system, which a lot of people think is horrible. In all reality, a properly working emission system on a stock Fox Mustang doesn't decrease horsepower. The problem is most people don't like weird looking parts under the hood, and when you go to modify your engien the emissions can then be a problem.

My car has all the working emssion system components on it, and I've installed headers, x-pipe w/cats, and cat back with a 3:73 rear gear and it runs great. Plus if emssion testing comes back I'll be okay.
On my last 98 GT, I put on a BASSANI offroad X pipe. I picked up 3 MPG city and 5 MPG highway. And enough horsepower to feel. It also changed the sound a LOT. So you will pardon me for not buying the "they don't restrict much"

BTW, we had it sniffed and it still passed without the cats on. Clean enough without them. Thats what makes me not feel bad about thumbing my nose at emissions regs. It should only matter if you pass the sniff or not. It should only matter if you burn clean, it should not matter if you have cats or not. Besides, 3 to 5 MPG better should count for something. That is a 10-20% improvement. Cats are a joke. They may have done something on the old carbureted engines, but I do not believe there is much benefit to them on the newer computer controlled engines. It is an old technology and an old regulation that dies hard.

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