# Cat delete?



## grampsd (Aug 22, 2011)

Hey Fellas, 

Im new to the forum and new to owning an 06 gto. It has the magnaflow x pipe cat back system on it, and im not sure its quite loud enough for me. I want a little more sound and thought about removing the cats but im not sure how because no o2 simulators are available. can u only do it with a tune? What if u do it without a tune? Just wondering if i should do it or will it lose back pressure and power too? 

Any advice is appreciated...


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## Mddrummer911 (Jul 9, 2011)

Was in the same situation as you a few weeks ago. A tune is the only way to get around the o2. The diablo handheld, or a custom hp tune if you can find anyone that knows what they are doing. I ended up buying a set of the loudmouth1 resonators from SLP for about $150 and had a muffler shop cut out the old magnaflow mufflers and replace with the SLP. Sounds and looks great. Gives a nice aggressive toan at start, it roars at wot! But quit ebough at cruising speeds... Very little drone inside the car. Shop charged me $50 to weld then up, so I only have $200 in the swap over... That was the best way I could come up with to make it louder


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## svede1212 (Nov 1, 2005)

You don't have to tune out the rear O2 but it will throw a check engine light if you don't. It doesn't do anything else


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## Poncho Dan (Jun 30, 2009)

Change the mufflers to something else. Deleting the cats is going to be much more of a pain in the ass. They're not nearly as accessible.


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## grampsd (Aug 22, 2011)

The car will run fine until I get it tuned and the rear 02's deleted from computer.....is that right? The only cats on the car now are right up by the manifold, with 1 sensor just in front and 1 about a foot behind them. I want a little bit of a power gain obviously and a little sound increase. I don't mean to be redundant, but I drive the car everyday cant afford it to run terrible right out of th exhaust shop. Nearest tuner is 2hrs away.....


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## Mddrummer911 (Jul 9, 2011)

The rear o2 sensor ONLY monitors the cat, that it is burning off exhaust efficiently. It's emissions only, will not affect drivability other than throwing a check engine light.


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## Mddrummer911 (Jul 9, 2011)

I would suggest if you are set on removing your cats, to get a set of catless mids. Can pick them up for around $200 then you could install yourself and not have to pay a exhaust shop, if you can even find one that will do it (removing cats if caught is a huge fine for a shop). Also you could always bolt the stocks back up if you wanted or didn't like it. Just my opinion


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## AlanSr (Jan 4, 2008)

I cut mine off a few months back. I have res delete and FM Super 44's; it was a night and day difference when I cut mine off. It sounds amazing!!! Cold starts are awesome, WOT will give you the old school muscle car feel, but HighWay cruising does give some drone inside. My power went up "don't have numbers" but you can tell and my MPG's went from 16.9-18.8 in a mixture of city and highway.
However you will notice the smell when sitting a stop lights or if you let your car warm up in the garage. 

I also got just a little popping when coming off the highway.

Also I'm reg'd in a state with no emissions test.....


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## Poncho Dan (Jun 30, 2009)

Really I wouldn't mess with the factory cats... it's not going to net you anything other than wasted time. Just change the mufflers. Pulling the cats are going to give you *minimal* gains at best and make the car stink. Hollowing them out will more than likely rob you of power. Like I said, if you go after the cats you have to get up in a tight spot and probably have to drop the whole midpipe to get at them to cut them out and weld in a "test" section. A wise cop might be able to smell the fact that you don't have the converters on, too. Just keep that in mind.

I can see getting catless mids with a set of headers to save a couple bucks, but you might as well do the environment a favor with the factory manifolds. It's not like they cork up the exhaust.


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## Johnson_05goat (Oct 13, 2011)

alright i have read this before and now im a member as of today, i have a 05 goat, yellow whatever...
but i had the resinator cut out so its true dual, stock intake mani's and flowmaster 40's 
i have the diablo sport tuner my car is tuned with it but im cutting my cats off and i need to know exactly how to do it. just to turn the rear 02's off? and will it make me lose mpg. i average half way decent gas milage for this car. so just let me know guys thanks.,,


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## ViperT4 (Jul 18, 2010)

exhaust cut outs? just leave them open


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## svede1212 (Nov 1, 2005)

The _resonator_ (as like in _resonate_) doesn't have a cross over and so it was a "true dual" when you started. You can cut the cats off with a hacksaw and weld in a piece of pipe the same size as you took out. It will throw a code for the rear cats that you can get the CEL turned off with a tuner. It shouldn't significantly change whatever tune you have now as far as mileage. The front O2s maintain air fuel ratio under normal driving conditions anyways. A real tune never hurts though.


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## chilliwhiggerE (Mar 10, 2009)

I went with Magnaflow high flow cats and a resonator delete with bullet muffler (I'm running a 3"). Now if you will excuse me I have to go and install my Braille 21 lb battery, Ingalls torque damper and oil catch can.


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## o4gto (Jul 16, 2011)

what kind of smell do you get


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## 646904GTO (Feb 10, 2008)

o4gto said:


> what kind of smell do you get


Mine reminds me of the '70's


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## The_Madcat (Sep 30, 2011)

646904GTO said:


> Mine reminds me of the '70's



Back of the VW bus 70's or frat house 70's?


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## svede1212 (Nov 1, 2005)

Having no cats can has a rich petroleum smell as opposed to the rotten egg smell of cats. If you put in race gas no cats takes on the heady aroma of ambrosia


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## Agenthol302 (May 18, 2011)

AlanSr said:


> *My power went up "don't have numbers" but you can tell* and my MPG's went from 16.9-18.8 in a mixture of city and highway.
> However you will notice the smell when sitting a stop lights or if you let your car warm up in the garage.
> 
> *I also got just a little popping when coming off the highway*.


1. u werent able to tell the power difference and 
2. its called a backfire 

anway OP. to clerify u will only get a code and it will not affect the way the car drives...u dont even need to get the car tuned if u dont want...and as far as the backpressure goes cuz that wasnt answered. backpressure is a hoaux and u will be fine...the bends in the pipes are enough!
:cheers


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