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Removing Rear Cats

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Old 03-08-2007, 11:34 PM   #1
nappypalms
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Default Removing Rear Cats

I went up to a local exhaust shop to talk to them about removing my rear catalytic converters,
and as soon as I mentioned removing cats to this guy there he freaks out and says No Way that's a $25,000 fine.

Is this true? LoL. I was thinking about removing them when I get my Mac Catback system installed.

I know that in some states it may be illegal, but I live in Texas and have seen multiple mustangs and other cars that have offroad pipes or removed cats.
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Old 03-08-2007, 11:38 PM   #2
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Default RE: Removing Rear Cats

I know it is in Ca. yet I don't have rear cats. It's called 'DIY'
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Old 03-08-2007, 11:39 PM   #3
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Default RE: Removing Rear Cats

There are some states where a shop can be fined for removing the cats, but all you have to tell them is that this will be an off/road track car only, there fore that makes it legal. That's what I had to do with my GT, and it's nothing but DD.
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Old 03-08-2007, 11:40 PM   #4
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Default RE: Removing Rear Cats

How hard is this to Do It Yourself? LoL.
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Old 03-08-2007, 11:42 PM   #5
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Default RE: Removing Rear Cats

Well semi easy if you can manage to get your car high enough off the ground to work on it, but you'll also need to know how to weld, because even those these systems "BOLT ON/UP" they still need to be welded together at certain points.
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Old 03-08-2007, 11:45 PM   #6
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Default RE: Removing Rear Cats

Not hard at if you can weld. I used a sawzall to cut the cats off and got some 2" pipe to fit inside the 2.25" to replace the cats. The passenger side cat had the 02 bung in the cat so that side needed a bung. If you can't weld do as jthorn9 suggested and tell them it's going to be a race car and used off road only.
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Old 03-08-2007, 11:50 PM   #7
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Default RE: Removing Rear Cats

I'll have to try the Off road/track use story haha I don't know how to weld yet.

Do ya'll think removing the rear cats would make the mac catback any louder?

Thanks for the suggestions guys.
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Old 03-09-2007, 01:48 AM   #8
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Default RE: Removing Rear Cats

It made my exhaust louder. Those rear cats are the biggest cats in the system so getting rid of them really helps with the sound.
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Old 03-09-2007, 02:56 AM   #9
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Default RE: Removing Rear Cats

Would the car still pass emissions with just the front two cats on it?
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Old 03-09-2007, 03:32 AM   #10
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Default RE: Removing Rear Cats

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ORIGINAL: MustangMike2001

Would the car still pass emissions with just the front two cats on it?
Probably not, but it will help reduce some pollution.
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Old 03-09-2007, 11:29 AM   #11
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Default RE: Removing Rear Cats

it is illegal to remove functioning cats on any post 1973 vehicle in all 50 states. yes the federal gov't can issue a $25,000 fine for it. some states don't have emissions laws and don't enforce it. in my area we have emissions and no garage will remove the cats unless an CARB CERTIFIEDcatted H-pipe or X-pipe is replacing it.

just to the south of me there are 2 counties in my area of PA that don't have emissions and they will remove cats IF you are a resident of those counties
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Old 03-09-2007, 12:02 PM   #12
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Default RE: Removing Rear Cats

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ORIGINAL: MustangMike2001

Would the car still pass emissions with just the front two cats on it?











Hell no but luckily we don't have smog checks up here. If we ever do the cats will go back on.
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Old 03-09-2007, 12:06 PM   #13
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Default RE: Removing Rear Cats

Gotta love AL, no inspections or emissions. I heard that macs sound fine on a catted setup, but O/R setup you will probably wanna switch to flows or force pros.
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Old 03-10-2007, 09:15 PM   #14
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Default RE: Removing Rear Cats

what about if you are replacing them with high flow cats?
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Old 03-10-2007, 10:48 PM   #15
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Default RE: Removing Rear Cats

Quote:
ORIGINAL: MustangMike2001

Would the car still pass emissions with just the front two cats on it?
yes the car will pass a smog check without the rear cats as long as you keep the rear O2 sensors in place
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Old 03-11-2007, 12:33 AM   #16
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Default RE: Removing Rear Cats

No checks in Florida.
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Old 03-11-2007, 12:59 AM   #17
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Default RE: Removing Rear Cats

Quote:
ORIGINAL: cobra232

Quote:
ORIGINAL: MustangMike2001

Would the car still pass emissions with just the front two cats on it?
yes the car will pass a smog check without the rear cats as long as you keep the rear O2 sensors in place
So if you take the rear cats out...and keep the rear O2 sensors in place it wont kick any lights on?? and i really dont want to have to change out my MAC cat back exhaust, but fastfall90 said that mac doesnt sound that good with a non-catted setup...anybody else heard a MAC system without cats? and can any muffler shop custom make me a divorced setup? and how is the sound of the exhaust going to change if i go divorced... well lets say for now i leave the cats on. if i just go divorced is my exhaust going to really sound any different? or will i have to do something with the cats for it to make a difference in sound.
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Old 03-11-2007, 01:36 AM   #18
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Default RE: Removing Rear Cats

+1 to that no checks in florida!!
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Old 03-11-2007, 03:34 AM   #19
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Default RE: Removing Rear Cats

Quote:
ORIGINAL: Sparks232

Quote:
ORIGINAL: cobra232

Quote:
ORIGINAL: MustangMike2001

Would the car still pass emissions with just the front two cats on it?
yes the car will pass a smog check without the rear cats as long as you keep the rear O2 sensors in place
So if you take the rear cats out...and keep the rear O2 sensors in place it wont kick any lights on?? and i really dont want to have to change out my MAC cat back exhaust, but fastfall90 said that mac doesnt sound that good with a non-catted setup...anybody else heard a MAC system without cats? and can any muffler shop custom make me a divorced setup? and how is the sound of the exhaust going to change if i go divorced... well lets say for now i leave the cats on. if i just go divorced is my exhaust going to really sound any different? or will i have to do something with the cats for it to make a difference in sound.
taking the rear cats off and still using the rear O2 sensors will not throw a check engine light as long as the O2's are not further than 12" behind the first cats.

going divorced will make it alittle deeper and alittle louder but your better off removing the rear cats. it will sound Ok like that even though i don't care for MAC's. they will buzz at higher rpm's no way around that with MAC mufflers
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mods to complete
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Old 03-11-2007, 03:58 AM   #20
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Default RE: Removing Rear Cats

Quote:
ORIGINAL: cobra232

Quote:
ORIGINAL: Sparks232

Quote:
ORIGINAL: cobra232

Quote:
ORIGINAL: MustangMike2001

Would the car still pass emissions with just the front two cats on it?
yes the car will pass a smog check without the rear cats as long as you keep the rear O2 sensors in place
So if you take the rear cats out...and keep the rear O2 sensors in place it wont kick any lights on?? and i really dont want to have to change out my MAC cat back exhaust, but fastfall90 said that mac doesnt sound that good with a non-catted setup...anybody else heard a MAC system without cats? and can any muffler shop custom make me a divorced setup? and how is the sound of the exhaust going to change if i go divorced... well lets say for now i leave the cats on. if i just go divorced is my exhaust going to really sound any different? or will i have to do something with the cats for it to make a difference in sound.
taking the rear cats off and still using the rear O2 sensors will not throw a check engine light as long as the O2's are not further than 12" behind the first cats.

going divorced will make it alittle deeper and alittle louder but your better off removing the rear cats. it will sound Ok like that even though i don't care for MAC's. they will buzz at higher rpm's no way around that with MAC mufflers
Yea ive noticed the buzz at higher rpm's...sounds pretty good i think for the price, i dont know how much more $ im gonna invest into this car though...im thinking about getting a Mach 1...so i think i should just save for mods for that car..
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Old 03-11-2007, 03:58 AM
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