Want to remove the cat.
Thread Starter
Teching In
Joined: May 2010
Posts: 23
Likes: 0
From: Ohio
Want to remove the cat. Okay, so I have been coming up with a plan all summer on what to do to my car. I have already installed a K&N CAI. I also have ordered Doug Thorley headers, Hooker Aerochamber mufflers, and exhaust tips. Now I just need to get into the exhaust shop. I plan to have the resonator deleted. I want the cat deleted but the guy at the exhaust shop said he wouldn't do it; so I'm thinking I will cut it out myself and take it there so he has to put something-something as in a pipe- in its place.
My main concern is this: Will deleting my cat hurt my car? I plan to get a tune as soon as I can once the exhaust additions are finished.
Like I said I would really like to delete the cat. We have no emissions tests where I live, so this would be ideal. But I could also go the high-flow route if I have to.
I have already done a lot of research on the forum, so I am not intentionally asking a repeat question if someone has already asked this.
My main concern is this: Will deleting my cat hurt my car? I plan to get a tune as soon as I can once the exhaust additions are finished.
Like I said I would really like to delete the cat. We have no emissions tests where I live, so this would be ideal. But I could also go the high-flow route if I have to.
I have already done a lot of research on the forum, so I am not intentionally asking a repeat question if someone has already asked this.
Banned
Joined: Dec 2008
Posts: 1,737
Likes: 0
From: Almost Arkansas, LA
I've been catless for a year and everything is fine. However without a tune, my performance is severely hurt and my plugs are bad. As long as you get the tune as soon as you can, you'll be fine. 
By the way, I took the downpipe off myself, brought it to a local shop, and they cut it off and welded my cutout in its place.
By the way, I took the downpipe off myself, brought it to a local shop, and they cut it off and welded my cutout in its place.
Staging Lane
Joined: Jul 2010
Posts: 94
Likes: 0
Okay, so I have been coming up with a plan all summer on what to do to my car. I have already installed a K&N CAI. I also have ordered Doug Thorley headers, Hooker Aerochamber mufflers, and exhaust tips. Now I just need to get into the exhaust shop. I plan to have the resonator deleted. I want the cat deleted but the guy at the exhaust shop said he wouldn't do it; so I'm thinking I will cut it out myself and take it there so he has to put something-something as in a pipe- in its place.
My main concern is this: Will deleting my cat hurt my car? I plan to get a tune as soon as I can once the exhaust additions are finished.
Like I said I would really like to delete the cat. We have no emissions tests where I live, so this would be ideal. But I could also go the high-flow route if I have to.
I have already done a lot of research on the forum, so I am not intentionally asking a repeat question if someone has already asked this.
My main concern is this: Will deleting my cat hurt my car? I plan to get a tune as soon as I can once the exhaust additions are finished.
Like I said I would really like to delete the cat. We have no emissions tests where I live, so this would be ideal. But I could also go the high-flow route if I have to.
I have already done a lot of research on the forum, so I am not intentionally asking a repeat question if someone has already asked this.
Once you have it removed, you will need a tune for 2 reasons.
1) you have 2 O2 sensors. one is a primary that monitors AFR around 14.7 and the other checks to make sure the cat is working properly. So if you remove your cat, your VCM will set a DTC of P0420 (low cat efficiency) and your SES lamp will be on all the time. So you will have to either buy HP tuners or have someone with it turn off those corresponding DTC's. You can buy a cat simulator, but dont waste your money, you have to have it tuned anyways by someone with HP tuners. May as well have those associated DTC's shut off.
2) Removing the cat will change the volumetric efficiency of the engine requiring you to re-tune it to take full effect of the better flow.
A word to the wise. I wouldnt go blowing your brains out on a bunch of mods. In my time I've seen guys spend mega time or mega money on headers, cams and LS6 manifolds hoping for better power. IMHO, the gains they got were very small compared to the cost. Like you I researched this very well. I made the choice to bypass all that and go turbo.
Cheers
Okay, so I have been coming up with a plan all summer on what to do to my car. I have already installed a K&N CAI. I also have ordered Doug Thorley headers, Hooker Aerochamber mufflers, and exhaust tips. Now I just need to get into the exhaust shop. I plan to have the resonator deleted. I want the cat deleted but the guy at the exhaust shop said he wouldn't do it; so I'm thinking I will cut it out myself and take it there so he has to put something-something as in a pipe- in its place.
My main concern is this: Will deleting my cat hurt my car? I plan to get a tune as soon as I can once the exhaust additions are finished.
Like I said I would really like to delete the cat. We have no emissions tests where I live, so this would be ideal. But I could also go the high-flow route if I have to.
I have already done a lot of research on the forum, so I am not intentionally asking a repeat question if someone has already asked this.
My main concern is this: Will deleting my cat hurt my car? I plan to get a tune as soon as I can once the exhaust additions are finished.
Like I said I would really like to delete the cat. We have no emissions tests where I live, so this would be ideal. But I could also go the high-flow route if I have to.
I have already done a lot of research on the forum, so I am not intentionally asking a repeat question if someone has already asked this.
And did I read right GXPgirl if so May I say Welcome!! and LS4_DeltaV
this is here car and some people dont have 5k to improve there car so be tolerant And
LS4_DeltaV also Welcome
this is here car and some people dont have 5k to improve there car so be tolerant And
LS4_DeltaV also Welcome
Thread Starter
Teching In
Joined: May 2010
Posts: 23
Likes: 0
From: Ohio
Thanks Mels SS, yes you did read right I am a girl.
I bought my headers from dougthorleyheaders.com last week. They came today.
I realize I could go 3" catless downpipe, but I want the exhaust shop to just put something in. Besides the guy at the exhaust shop wants to just hook my stock y-pipe back up to the headers so I don't think a 3" downpipe will fit due to diameter differences.
I just wanted to be sure that cutting my cat out wouldn't hurt anything.
I'm definitely getting a tune afterwards though; I already have a place lined up.
I bought my headers from dougthorleyheaders.com last week. They came today.
I realize I could go 3" catless downpipe, but I want the exhaust shop to just put something in. Besides the guy at the exhaust shop wants to just hook my stock y-pipe back up to the headers so I don't think a 3" downpipe will fit due to diameter differences.
I just wanted to be sure that cutting my cat out wouldn't hurt anything.
I'm definitely getting a tune afterwards though; I already have a place lined up.
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Staging Lane
Joined: Jul 2010
Posts: 94
Likes: 0
Yup - just trying to give some sage advice. Im hoping there is a much more affordible option real soon for the LS4 boost crowd.
I just dont like seeing well intentioned folks get let down after spending there hard earned doe on things that dont live up to there expectations.
But you rasie a good point. We should complie a list of know gains for all these smaller mods. This way folks can make an informed choice on what they buy. Going into things with you eyes wide open usually results in a happy ending. Thats what its all about. Fun.
Cheers!
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Registered User
Joined: Mar 2010
Posts: 31
Likes: 0
From: Boynton Beach, FL
U should ask around to find a shop that will remove ur cat....down here, there's a ton of shops that will do whatever we want for exhaust. No emissions down here in fl either :-) like everyone else said, definitely get it tuned. My buddy tuned my gxp and it runs sooooo much better! Good luck girly!
I have Doug Thorley Headers and I went this route after selling my Hogan catless DP. I welded a 3" ZZP SS flex to the header collector itself then I mated it with a fake cat and welded that to the rest of the cat-back. Worked out great. Here are the links.
http://www.zzperformance.com/grand_p...=671&catid=110
http://www.siliconeintakes.com/produ...4e957b049bdf86
Hope this helps ya and welcome to the club.
-Mike
http://www.zzperformance.com/grand_p...=671&catid=110
http://www.siliconeintakes.com/produ...4e957b049bdf86
Hope this helps ya and welcome to the club.
-Mike
Thanks for the welcome guy!
Yup - just trying to give some sage advice. Im hoping there is a much more affordible option real soon for the LS4 boost crowd.
I just dont like seeing well intentioned folks get let down after spending there hard earned doe on things that dont live up to there expectations.
But you rasie a good point. We should complie a list of know gains for all these smaller mods. This way folks can make an informed choice on what they buy. Going into things with you eyes wide open usually results in a happy ending. Thats what its all about. Fun.
Cheers!
Yup - just trying to give some sage advice. Im hoping there is a much more affordible option real soon for the LS4 boost crowd.
I just dont like seeing well intentioned folks get let down after spending there hard earned doe on things that dont live up to there expectations.
But you rasie a good point. We should complie a list of know gains for all these smaller mods. This way folks can make an informed choice on what they buy. Going into things with you eyes wide open usually results in a happy ending. Thats what its all about. Fun.
Cheers!
Alabama Guy can we get a sticky for this?
first off welcome!!!!, second, if your getting headers then you dont need the hogan downpipe (correct me if im wrong) .. just go catless you will love it, should sound very agressive.
Im cat-less and i love it. I have the DT headers sitting in my garage waiting to install. I currently have a Hogan non catted down pipe but that will be getting taken off and put up for sale since you dont need it when you get headers (94ss06gxp you are correct) I ran about 4 months without a tune when i got my non catted down-pipe and it didnt hurt anything. just ran a tad bit rougher. I got lucky and got an ok from a local exhaust shop to get my exhaust welded up with out there being a cat. you just have to look around. also it is recommended to replace the flex on the cross over pipe on the headers, it is know to whistle. you will need it to be 2.5 inches and 6 inches long. also welcome to the forum!
Launching!
Joined: Mar 2010
Posts: 265
Likes: 0
From: Morristown, IN
I'm about in the same boat, except I don't have my tips yet, we'll get those next week.
Anywho, just find another shop. Some places won't do it because they can be fined for doing so.
If you have headers you won't want to get a downpipe, it's kind of a waste of money to by that then have to cut most of out because your headers will run so far down.
I just found a shop that will run new exhaust tubing from my header collector all the way back to my mufflers, taking out the cat and resonator. Mine will come out of the header, into a cutout, then back to the mufflers and tips, all being 3 inch.
I'm not sure how long it will be until you do yours, but I should have mine done in a few weeks. I will be sure to get a lot of pics to post up.
As far as a tune goes, it will be ideal to do it after. Adding the headers and removing the cat will trip your check engine light and a tune will get rid of that. Also, some people have on here have had rich condtions after doing these mods.
Anywho, just find another shop. Some places won't do it because they can be fined for doing so.
If you have headers you won't want to get a downpipe, it's kind of a waste of money to by that then have to cut most of out because your headers will run so far down.
I just found a shop that will run new exhaust tubing from my header collector all the way back to my mufflers, taking out the cat and resonator. Mine will come out of the header, into a cutout, then back to the mufflers and tips, all being 3 inch.
I'm not sure how long it will be until you do yours, but I should have mine done in a few weeks. I will be sure to get a lot of pics to post up.
As far as a tune goes, it will be ideal to do it after. Adding the headers and removing the cat will trip your check engine light and a tune will get rid of that. Also, some people have on here have had rich condtions after doing these mods.