Removal of the rear cats...

[airjordan2k8]

Question how much does this usually run? as i might be doing this today..

[tbone]

I wouldn't pay more than $50-$75.

[airjordan2k8]

Good deal cause theyre charging me $60 bucks and do they just remove that or do they add another piece of pipe? Sorry but im kinda new to this rear cat removel...

[fastblackmerc]

Good deal cause theyre charging me $60 bucks and do they just remove that or do they add another piece of pipe? Sorry but im kinda new to this rear cat removel...

They are removing a section of the exhaust... they will have to replace it with something!

[martyo]

They are removing a section of the exhaust... they will have to replace it with something!

I use Jedi mind force to channel my exhaust.

[babbage]

Question how much does this usually run? as i might be doing this today..

Keep in mind the (2) cats they are cutting out are worth $50 cash EACH -- if not damaged or hollowed out.

[airjordan2k8]

Keep in mind the (2) cats they are cutting out are worth $50 cash EACH -- if not damaged or hollowed out.
So your saying i should keep these huh?

[tbone]

They replace them with small pieces of tubing.

I didn't save mine. They would just take up space in the garage. I guess you could try to sell them on here.

[Pat]

Please don't be offended but why do you want to remove your rear CATS?
Texas has emissions control inspection in Dallas, County in which your town of Seagoville is located. Texas only requires an OBDII check not a exhaust pipe test.
However, They may look under the car to determine if the emissions system has been disturbed.

The ECU must be reprogrammed to delete the rear cat logic or you will get a check engine lite IIRC. This may also set a "not ready" code in the ECU.
Other than more exhaust sound I don't believe there is any appreciable horsepower gain.

I see on these forums where many drivers are deleting their rear CATS but have yet to understand the benefits.

Would you care to explain your reasoning behind this modification?

Again, it's your car but others may be thinking of doing the same mod and it would be helpful to know the benefits that you expect.

Thanks,

[TAKEDOWN]

So your saying i should keep these huh?

I believe he means don't get ripped off removing the rear cats and handing over $100.00 dollars worth of material too! I guess reminding the person removing the cats they also make a bit of money from the leftover parts.

[airjordan2k8]

Please don't be offended but why do you want to remove your rear CATS?
Texas has emissions control inspection in Dallas, County in which your town of Seagoville is located. Texas only requires an OBDII check not a exhaust pipe test.
However, They may look under the car to determine if the emissions system has been disturbed.

The ECU must be reprogrammed to delete the rear cat logic or you will get a check engine lite IIRC. This may also set a "not ready" code in the ECU.
Other than more exhaust sound I don't believe there is any appreciable horsepower gain.

I see on these forums where many drivers are deleting their rear CATS but have yet to understand the benefits.

Would you care to explain your reasoning behind this modification?

Again, it's your car but others may be thinking of doing the same mod and it would be helpful to know the benefits that you expect.

Thanks,
Honestly i just wanted a more sound out of the exhaust thats it so this does cause the engine light to come on? and your also saying that i wont pass the inspection with this done?

[marauder410]

i removed my rear cats and noo you willl not get a check engine code

[tbone]

.....................

[Granddaddy Marq]

I use Jedi mind force to channel my exhaust.


Jedi Exhaust mod! Is this something offered at Mo's Speed Shop, and can you Quote me a price on that?:lol:

[airjordan2k8]

You need a tune that turns off the rear sensors. Once you have that, you will pass the exam UNLESS they do a visual inspection.
So without a tune i wont pass the inspection is that what your saying?

[tbone]

.............................. .

[airjordan2k8]

Yes, you need a tune that specifically turns off the rear sensors or your light will come on and you will not pass inspection.
Ok thanks buddy guess i gotta get that then first..

[JOEMERC]

I was told you could remove without a check engine light coming on, I hear different stories about this.has anyone removed them with no issues what so ever, like not having to turn off the o2 rear sensors.being the cats are after the sensor,should not be an issue.

[tbone]

i was told you could remove without a check engine light coming on, i hear different stories about this.has anyone removed them with no issues what so ever, like not having to turn off the o2 rear sensors.being the cats are after the sensor,should not be an issue.....


................

[MrBluGruv]

MISINFORMATION PEOPLE!


Goodness, people have only been doing this for years, I would've thought it'd be understood now.


Your REAR catalytic converters have no efficiency monitors on them, so removing them makes no difference to the computer, it will never know the difference, you WILL NOT throw a code.


The exhaust chain in regards to emissions control flows like this:

Manifold -> 02 sensor (for A/F monitoring) -> primary catalyst (smaller set) on the down pipe -> 02sensor (for catalyst efficiency monitoring) -> secondary catalyst (larger set) -> rest of exhaust.


You should most definitely notice a volume increase unless you just have super quiet mufflers, in which case you may consider going that route first.

[airjordan2k8]

MISINFORMATION PEOPLE!


Goodness, people have only been doing this for years, I would've thought it'd be understood now.


Your REAR catalytic converters have no efficiency monitors on them, so removing them makes no difference to the computer, it will never know the difference, you WILL NOT throw a code.


The exhaust chain in regards to emissions control flows like this:

Manifold -> 02 sensor (for A/F monitoring) -> primary catalyst (smaller set) on the down pipe -> 02sensor (for catalyst efficiency monitoring) -> secondary catalyst (larger set) -> rest of exhaust.


You should most definitely notice a volume increase unless you just have super quiet mufflers, in which case you may consider going that route first.
Thank you sir for your input on this, so then i should be fine doing this...:D

[tbone]

Yeah, you're right. I was thinking about the fronts. I want to delete the front cats when I get headers so the rear O2 sensors must be turned off for that. Sorry. Brain fart.

[MrBluGruv]

Yeah, you're right. I was thinking about the fronts. I want to delete the front cats so the rear O2 sensors must be turned off for that. Sorry. Brain fart.

Yeh. Actually, with the easy availability of the Lidio tune (as well as others maybe, I had just gone with Lidio at the time), doing the full cat removal is actually remarkably simple on this car compared to some other vehicles.

It's a pain in the ass on my Camaro, I mean with the money I'd put into getting a special tune, which are typically considerably more than for the Marauder unless you mail in your entire PCM, just to run like a $200 off-road downpipe setup, one may as well just buy headers for $355 that bolt up to the factory cat-back and run that same tune.

I mean, it's nice for a mod like headers to be so cheap, but at the same time small mods are not cost effective at all really. :depress:

[tbone]

I deleted the rears for sound. I put Magnaflows on and it sounded stock. So off came the rear cats and on came the nice sound. That definitely made it worth it.

[FrankJAG]

Your check engine light will come on, you won't pass inspection. And as mentioned, if they look for the cats you'll fail inspection until you put them back on.
Not a worthwhile "mod" in my opinion.

[tbone]

If you are talking to me, there is no visual inspection here.

My rear sensors are turned off, rear cat deleted, no light, and I passed the OBDII inspection with no problem. The front sensors are before the first cats, so how would the car know if the cats are gone? I'm golden.

If you're referring to airjordan, mrblugrv is correct.

[FrankJAG]

Sorry tbone, I meant to OP. Most inspection stations check for cats here in Texas.

[tbone]

I read up on it. Sounds like it's hit or miss down there on the visual.

The thing is, we have four cats. He can point to the fronts and say they are on the car. Plus no codes thrown. What can they say?

The sound increase really is worth it.

http://www.youtube.com/watch?v=6dBWYI6HHdA&list=LLBub0tbEpo6R8jPsLwF8TdQ&feature=mh_lolz

[fastblackmerc]

I read up on it. Sounds like it's hit or miss down there on the visual.

The thing is, we have four cats. He can point to the fronts and say they are on the car. Plus no codes thrown. What can they say?

The sound increase really is worth it.

http://www.youtube.com/watch?v=6dBWYI6HHdA&list=LLBub0tbEpo6R8jPsLwF8TdQ&feature=mh_lolz

Believe me it will be mostly a miss....

Not to many cars have 2 set of cats. When hey do the visual they will see a cat on each side.... they will have no clue that the Marauder is supposed to have 4 cats.

Not just the sound increase, you'll get a better breathing exhaust.

[MrBluGruv]

Most inspection stations check for cats here in Texas.

I guess that's one of the few perks of living here in San Antonio, never once had anyone look under the car. Or under the hood. Hell I once found a shop that asked for my plate #, VIN #, and mileage, and sold me the sticker right there. :eek:

[TAKEDOWN]

Sorry tbone, I meant to OP. Most inspection stations check for cats here in Texas.

Do they look for 4, or after seeing the 2 there would they even know?

[airjordan2k8]

These people are saying that ill lose gas mileage and that it has 4.sensors

[FrankJAG]

Do they look for 4, or after seeing the 2 there would they even know?
Dunno about that, they have always looked when I have gone in for my inspection.

[FrankJAG]

These people are saying that ill lose gas mileage and that it has 4.sensors
You have 2 upstream and 2 downstream sensors. You can do without the rears by having them turned off by having a guy that is a tuner deactivating them via programming.
Just saying, allot of expense for not allot of benefit other than being noisier, I don't think you'll see allot (if any) increase in horsepower. Just my two cents LOL

[SilverSport]

If you are worried about the visual inspection you can always gut the cats. Horsepower wise it's not the best thing to do. The hollowed cats will create turbulence in the system and will not flow as well as a straight pipe. It will however give you more volume and not raise any suspicions come smog check time. A properly sized piece of staight pipe hammered inside the hollowed cat will provide the best of both worlds while providing a minimal restriction to exhaust flow.

[ctrlraven]

Removing the rear cats will not cause any CEL code, period.

The rear cats sit right at the cross member where the transmission mount is so you say the trans was pulled and they couldn't unbolt the exhaust so they just cut the pipe to drop the transmission.

I had my rear cats deleted and went through 1 or 2 emissions testing here in Maryland, they did walk around with an angled mirror checking under the car and passed. Went through emissions last year with my whole new exhaust and only two magnaflow cats, they didn't say anything besides "sounds like a beast!".

When I removed my rear cats I noticed a better exhaust note and slightly better mid-high rpm range power, I also knocked a tenth off my 1/4, raced a Friday, removed the cats on Saturday and raced again on Sunday.

[tbone]

When I removed my rear cats I noticed a better exhaust note and slightly better mid-high rpm range power, I also knocked a tenth off my 1/4, raced a Friday, removed the cats on Saturday and raced again on Sunday.

Perfect. THAT's what I'm talkin 'bout!

You know, come to think of it, this is actually one of my favorite mods.
It sounded way too wimpy before, even with the Magnaflows.

[TUXrauder]

Okay, I did this yesterday and added the 4" Tips.... remembered that I was gonna video the sound prior....

No error codes, much MUCH better sound. I can slightly hear a difference on the highway, seriously not noticable but idle and when you get on it, a much better sound.

[airjordan2k8]

Well explained ctrlraven... the guy said he will do it anyway but do keep in mind it will use more gas is this true?? Love that i can come here for all my questions..

[MrBluGruv]

Well explained ctrlraven... the guy said he will do it anyway but do keep in mind it will use more gas is this true?? Love that i can come here for all my questions..

Tell that guy to explain to you exactly how it could use more gas.


I swear, the things people come up with these days. Makes me wonder if 9/10ths of the auto hobby exists on urban legend alone...

[tbone]

As long as it goes faster and sounds better, who cares about mileage?

[71cyclone]

As long as it goes faster and sounds better, who cares about mileage?
Good note / Mine sounds better [more rumble at idle - Mid range pulls harder and 1/2 to 3/4 mile per gallon gain and this is with a D.R. Tune :beer:

[airjordan2k8]

Ok well im by yalls word and getting this done...

[airjordan2k8]

Oops i meant going by yalls word

[ddrek0214]

Bro.. It won't cause an CEL to come on. It will make the exhaust sound a whole lot better even with factory mufflers. I can post a YouTube video of my mufflers with aero turbines before and after cat-delete if u want.

[ddrek0214]

Oh yea.. Removel(removal) is spelled wrong.lol! Seriously I guess it will depends on how your inspection goes and how you tell(lie) to your inspector. Or move to Alabama, not to brag, but I've heard cars that sound like monster trucks!(no mandatory inspections yet.)

[airjordan2k8]

Lol yea just saw that

[airjordan2k8]

Where's that video??

[Pat]

OK, I stand corrected about the rear cat delete and no CEL associated with it.

But that still leaves the logic question. Tunes usually have the rear cat logic turned off. Wouldn't that give a "not ready" code for that parameter?

I took my car into the dealership for a diagnosis on a unrelated problem and they informed me I needed two CAT assemblies. I didn't get them but they sent me to an exhaust shop (sub contractor) to have the system tested using some sort of pressure tester and drilling a small hole in the exhaust pipe. System checked OK, later I thought maybe it was because my CAT logic was turned off.

My point being, something in the OBDII test keyed the technician that the CAT system was faulty. Would the OP's car also fail this test if logic was turned off?

Don't mean to be picky but it may help to get answers before he commits to alterations of his emissions components.
The fine for this is tremendous. Go to any muffler shop and the warning signs are clearly posted.

For those of us in non-emissions testing states, no big deal. What happens when you sell the car and the new buyer gets tagged.

Sorry for being a pain in the arse.

[ddrek0214]

((((BEFORE))))Check out this video on YouTube:

http://www.youtube.com/watch?v=OIHvajo2FGc&feature=youtube_gdata_player


Sent from my iPod

[ddrek0214]

((((AFTER))))Check out this video on YouTube:

http://www.youtube.com/watch?v=Ubg4meFwZFw&feature=youtube_gdata_player


Sent from my iPod

[justbob]

I use Jedi mind force to channel my exhaust.

O.M.G. Marty! Quote worthy!






MISINFORMATION PEOPLE!


Goodness, people have only been doing this for years, I would've thought it'd be understood now.


Your REAR catalytic converters have no efficiency monitors on them, so removing them makes no difference to the computer, it will never know the difference, you WILL NOT throw a code.


The exhaust chain in regards to emissions control flows like this:

Manifold -> 02 sensor (for A/F monitoring) -> primary catalyst (smaller set) on the down pipe -> 02sensor (for catalyst efficiency monitoring) -> secondary catalyst (larger set) -> rest of exhaust.


You should most definitely notice a volume increase unless you just have super quiet mufflers, in which case you may consider going that route first.




Correct.



Your check engine light will come on
Incorrect.







If you are talking to me, there is no visual inspection here.

My rear sensors are turned off, rear cat deleted, no light, and I passed the OBDII inspection with no problem. The front sensors are before the first cats, so how would the car know if the cats are gone? I'm golden.

If you're referring to airjordan, mrblugrv is correct.
If what you say is true, then you can now remove the front cats too, but probably wouldn't sound the best using stock manifolds.

[airjordan2k8]

Im getting confused here.. WILL I BE OK IF I DO THIS?? Cause i went yesterday and after the guy told all that i asked my question on here to get a correct answer.. If its fine ima go ahead and do this today.

[ddrek0214]

Go ahead and do it, and don't look back. You won't regret it.

[bolsen]

Im getting confused here.. WILL I BE OK IF I DO THIS?? Cause i went yesterday and after the guy told all that i asked my question on here to get a correct answer.. If its fine ima go ahead and do this today.
Stop being a Nancy and DO IT!!! What's the worst that can happen? You fail your inspection and get them put back on for $50. Easy...

[PonyUP]

OK, I stand corrected about the rear cat delete and no CEL associated with it.

But that still leaves the logic question. Tunes usually have the rear cat logic turned off. Wouldn't that give a "not ready" code for that parameter?

I took my car into the dealership for a diagnosis on a unrelated problem and they informed me I needed two CAT assemblies. I didn't get them but they sent me to an exhaust shop (sub contractor) to have the system tested using some sort of pressure tester and drilling a small hole in the exhaust pipe. System checked OK, later I thought maybe it was because my CAT logic was turned off.

My point being, something in the OBDII test keyed the technician that the CAT system was faulty. Would the OP's car also fail this test if logic was turned off?

Don't mean to be picky but it may help to get answers before he commits to alterations of his emissions components.
The fine for this is tremendous. Go to any muffler shop and the warning signs are clearly posted.

For those of us in non-emissions testing states, no big deal. What happens when you sell the car and the new buyer gets tagged.

Sorry for being a pain in the arse.

This happened to me when I bought my first Marauder, took it for inspection not knowing the Cats were deleted, they checked and I failed.

Went to the shop, installed Hi-Flow Cats for a few hundred bucks, passed and din't notice a huge difference in the performance for the car or the sound.

I'd say he can do it, worst case scenario it will cost a few hundred dollars to get it back as a lesson learned

[tbone]

If what you say is true, then you can now remove the front cats too, but probably wouldn't sound the best using stock manifolds.

I'll remove them when I get the Stainless Works headers. Until then, my car has a perfect exhaust system, in my oh so humble opinion!:burnout:

[TAKEDOWN]

I'll remove them when I get the Stainless Works headers. Until then, my car has a perfect exhaust system, in my oh so humble opinion!:burnout:

HmmM... I shall wait and see what happens!

[tbone]

HmmM... I shall wait and see what happens!

Believe it Brutha!:beer:

[Black&Gifted]

This thread makes me laugh. Ton of misinformation with the truth sprinkle in here and there.

You should not fail inspection in Texas for removing the rear cats. All my ford vehicles have the rear cats removed (three currently and had 2 previously registered in Texas) and None have ever thrown a code or failed inspection. I'm in Houston.

EDIT: so people don't take my post the wrong way, I'll explain a bit what I mean: forums are a great source of information. problem is that everyone thinks they are experts and gives their two cents without thinking about what the OP asked, or ever worse, gives the OP wrong information. So the issue becomes having to dig through BS to find the real answer. The same logic applies when searching for old threads on an issue. Lots of discussion but no conclusion. For example, I posted a thread about using 98 cobra cams in a built supercharged application. I felt like one poster in the thread effectively was calling me an idiot becuase the topic "has been covered/beaten to death" and that I should have done a search. Well, I did search prior to posting and I didn't find a consistent answer. This same person then asked the exact same question that I had a couple days laters because he didn't know the answer. So I am left wondering why he posted in my thread saying the topic was covered?????? Point: too many opinions and not enough people in the know. Have a good day.

[Reek09]

I live in VA and I deleted my rear cats and put on flowmasters and everybody says my car is way louder than other MM's that's how they know its me! I did this about two years ago and no check engine light or nothing. I still have stock tips with the resonators and it still sounds like a beast. Even more when I get into it!

[ctrlraven]

I removed my 2nd set of cats a little over 5 years ago. 10/2010 I changed my complete exhaust.

[airjordan2k8]

im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..

[ddrek0214]

If your worried about gas mileage, do as I did and get a Honda civic..and drive the MARAUDER on the weekends and on special occasions.. But it's kinda hard to stay out of the MARAUDER when u have a 97hp civic.. MARAUDERS(aka Ms. Betty Black) are to fun to not drive them for a while, then get back in them.. It feels like a new car. But it might just be me..

[Black&Gifted]

im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..

Ok. I'm going to go against my own advice...lol

My opinion regarding the above and do what you will with it: in texas (not sure of other states...and this may even be a federal emissions law), it is "technically" not legal to remove any part of the OEM catalytic convertor system unless the system FAILED/is failing. So, if someone removes the rear cats, which is part of the emissions system, the car will "technically" fail inspection because it does not have the entire OEM emissions system. If a part failed, and it was replaced, the shop that replaced it is required to give you a ticket/write-up thingy explaining what failed and what was replaced, etc. You then would take this to inspection if ever questioned about it. IN THE REAL WORLD, none of the above matters. As long as the car has at least 2 cats and isn't throwing emissions codes, it should pass. I've only had one inspector look under the car in the 15+ registrations on vehicles of mine (all ford mod motor vehicles) with rear cats removed and he didn't say anything because THE CAR STILL HAD 2 CATS. 5 of those inspections was with no EGR setup on a boosted motor and everytime the inspector opened the hood all they would say is "bet she runs like a champ."

If you want to be technical regarding inspections, any car with an aftermarket CAI like the JLT (I think the exception may be the K&N) would "technically" an inspection....just saying.

Now, regarding gas mileage...how much did this muffler guy say you would lose? 1mpg? 5mpg? If removing the rear cats had a large effect on gas mileage, there would be threads galore on every mod motor website on the mighty internet....I have yet to find one. Could it happen, sure, why not, but the fact of the matter remains there are too many variables in gas mileage and removing one set of cats to free up exhaust flow doesn't come to the forefront for me. This is just my opinion. I am not an engineer but I base my answers on research and experience.

[Black&Gifted]

This happened to me when I bought my first Marauder, took it for inspection not knowing the Cats were deleted, they checked and I failed.

Went to the shop, installed Hi-Flow Cats for a few hundred bucks, passed and din't notice a huge difference in the performance for the car or the sound.

I'd say he can do it, worst case scenario it will cost a few hundred dollars to get it back as a lesson learned

Were all the cats deleted or just the rear cats?

[Black&Gifted]

I tell you what...I will be removing part of my exhaust from the engine block to the mufflers in a couple weeks (I hope). The parts being removed are the stock manifolds, front cats, straight pipe (i.e., rear cat delete) to 2.5 inch X-pipe to mufflers. If you are concerned about the consequences, get that and if there is a problem you can bolt your old system right back up.

[mrjones]

Bingo, just keep your cats that are cut off, and if you have problems, have the same shop put them back on. You could also take your car in and get a new inspection done and see if they check the cats visibly. If they do, you could have the cats taken out, put in a replacement pipe, and have bolt-in flanges put on your exhaust and on both the cats and the replacement pipes. That way you can bolt the cats in each year before inspection time.

I don't really have a desire to take my cats off, but I will say the two best sounding MMs I have heard in person both had only 1 pair of cats.

It could be worse. Some of the 96-98 4.6 Mustangs had 3 PAIRS of cats!

Do any of you other old farts out there remember back in the late 70s and early 80s when JC Whitney sold "test pipes"? Replaces the catalyctic converter "for test purposes only"!!! Hardeeharhar!

[ctrlraven]

Bingo, just keep your cats that are cut off, and if you have problems, have the same shop put them back on. You could also take your car in and get a new inspection done and see if they check the cats visibly. If they do, you could have the cats taken out, put in a replacement pipe, and have bolt-in flanges put on your exhaust and on both the cats and the replacement pipes. That way you can bolt the cats in each year before inspection time.

I don't really have a desire to take my cats off, but I will say the two best sounding MMs I have heard in person both had only 1 pair of cats.

It could be worse. Some of the 96-98 4.6 Mustangs had 3 PAIRS of cats!

Do any of you other old farts out there remember back in the late 70s and early 80s when JC Whitney sold "test pipes"? Replaces the catalyctic converter "for test purposes only"!!! Hardeeharhar!

Are you sure there were a third pair of cats? I know the mid-90's Ford was putting resonators in-line before the mufflers.

[tbone]

im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..

Are you going to believe some dork at Midas, or people that own these cars and drive them everyday?:confused:

[MrBluGruv]

I still don't get how someone would argue a noticeable negative impact on fuel economy from removing a secondary unmonitored set of cats. I'm thinking either he doesn't understand this car, he doesn't understand how emissions control systems work, or he's just feeding you a line to try to make you not want to attempt the modifications of your own mind instead of him having to refuse you.

[BigCars4Ever]

Well explained ctrlraven... the guy said he will do it anyway but do keep in mind it will use more gas is this true?? Love that i can come here for all my questions..
It'll use more gas cause you'll hit the go pedal harder more often to hear the sound!

[GetMeMyStogie]

Has anyone tried running with 4 cats and no mufflers? If the cats eat up a good proportion of the engine noise, maybe the mufflers aren't needed.

That might come off as ridiculous, but I really am curious. If the main reason people remove cats is for more sound, wouldn't removing or swapping the mufflers also work?

[airjordan2k8]

Thanks everybody for yalls input on all this.. got it done sounds a hellofalot better and its true i do give it a lil more pedal to hear it... thanks again.. very impressed with the results....

[tbone]

And of course the light has not come on......

[airjordan2k8]

And of course the light has not come on......
No sir, no light at all... :D

[TUXrauder]

im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..

I just did this very thing... removed rear cats this week... I have looked at my mileage and your mechanic is 100% accurate... does he sell tires too???? reason being, with the change in the sound, not only have my mileage went down, I am also loosing more tread from my tires.... cant make the connection though....

Wait, I think I get it, my car sounds so much better that I give it more gas (AKA HEAVY RIGHT FOOT) which A: means worse gas mileage and B: leaves my rubber on the road......

So, there... the mystery is solved....

Tux!

[airjordan2k8]

I'm loving this rear cat delete!!!!!!

[ctrlraven]

I'm loving this rear cat delete!!!!!!
Oh it gets better just wait..... but does start to cost more to hear more result. lol

[airjordan2k8]

Oh it gets better just wait..... but does start to cost more to hear more result. lol

Oh yea I know it does this is just for now.. $200 for the 40s

[Fosters]

Bingo, just keep your cats that are cut off, and if you have problems, have the same shop put them back on. You could also take your car in and get a new inspection done and see if they check the cats visibly. If they do, you could have the cats taken out, put in a replacement pipe, and have bolt-in flanges put on your exhaust and on both the cats and the replacement pipes. That way you can bolt the cats in each year before inspection time.

I don't really have a desire to take my cats off, but I will say the two best sounding MMs I have heard in person both had only 1 pair of cats.

It could be worse. Some of the 96-98 4.6 Mustangs had 3 PAIRS of cats!

Do any of you other old farts out there remember back in the late 70s and early 80s when JC Whitney sold "test pipes"? Replaces the catalyctic converter "for test purposes only"!!! Hardeeharhar!

My 96 and my 04 mustang both had 3 pairs of cats. Keyword, had. :D

Probably the best weight savings I've done to the 04 was putting in an aluminum prochamber, weighed like 800 lbs less than the stock midpipe. (or so it felt when the midpipe fell on my hand after undoing the last bolt - I was not expecting it to weigh so freaking much).

[Black Machine]

Does removing the rear cats make a code pop up or not?

[ctrlraven]

Has anyone tried running with 4 cats and no mufflers? If the cats eat up a good proportion of the engine noise, maybe the mufflers aren't needed.

That might come off as ridiculous, but I really am curious. If the main reason people remove cats is for more sound, wouldn't removing or swapping the mufflers also work?
For about 3 weeks I ran no mufflers and side exiting exhaust right in front of the rear tire. Let me tell you.... after the 3rd week I could stand the drone anymore. lol


Does removing the rear cats make a code pop up or not?
No.

[92BlackGT]

just got my rear cats deleted. car sounds way better and of course, NO CODE!!!!!

[tbone]

I'm moving to Florida next year. They wised up and got rid of testing altogether. Not that I have any problems here, but just one less PITA to worry about.:beer:

[Mest30]

Anyone know if you can delete the rear cats in California and still pass inspection?

[fastblackmerc]

Anyone know if you can delete the rear cats in California and still pass inspection?

If they know the MM comes with 2 sets of cats you'll certainly fail the visual. Usually an MM in good condition will pass the sniffer test with both sets of cats removed.

[Mebot]

I live in VA and I deleted my rear cats and put on flowmasters and everybody says my car is way louder than other MM's that's how they know its me! I did this about two years ago and no check engine light or nothing. I still have stock tips with the resonators and it still sounds like a beast. Even more when I get into it!

Cool someone from VA did it. We have emissions test every 2 yrs. Was wondering if deleting 2nd cats would make me fail inspection but after reading this thread not so much. Great!

Sent from my Samsung Droid Charge

[Mr. Man]

Anyone know if you can delete the rear cats in California and still pass inspection?


If they know the MM comes with 2 sets of cats you'll certainly fail the visual. Usually an MM in good condition will pass the sniffer test with both sets of cats removed.

:hmmm: Sitting here in my delirium I had a thought, for those of you who live in nanny states like California that have visual inspections would running two sets of free flow cats work to satisfy the DMV?:dunno:

[wizkiddrummer]

Can anyone confirm the size of the pipe before and after the cat?
I've searched before and there's a bunch of different answers.
I want to use a chain cutter to cut the cat out and then use the exhaust band clamps they sell to attach a new pipe with.

[tbone]

I'm 99% sure it's 2 1/2".

[justbob]

More like 2". Factory is puny.

Sent from my Ally while ruling the world from my toilet.

[tbone]

Ok 2 1/4".