Cats - able to be removed??

**GungHoPopsicle** · 12-10-2009, 04:27 AM

My car is registered in Memphis which means I don't have to pass emissions. With that being said, I've spoken with a mechanic friend of mine sometime ago about removing the cats but he said something about there being a lack of back pressure in doing so. Does anyone know if this is a safe thing to do or not? Keep in mind, this is a daily driver.

**tatertot91** · 12-10-2009, 05:07 AM

Nothing wrong with removing them, but why not just install headers and an ORY?

**GungHoPopsicle** · 12-10-2009, 05:14 AM

I definitely plan on getting headers. Don't know what ORY is or stands for though... Might wanna keep me informed on that one.

Does getting headers require that I have cats? I just want to get rid of them if they're not needed.

**tatertot91** · 12-10-2009, 05:18 AM

Originally Posted by GungHoPopsicle

I definitely plan on getting headers. Don't know what ORY is or stands for though... Might wanna keep me informed on that one.

Does getting headers require that I have cats? I just want to get rid of them if they're not needed.

If you install headers, in order for the headers to match up to the catback system towards the back of the car you need a y-pipe made for headers
You can either get a catted y-pipe, or an off-road y-pipe (ORY)
This would be better than punching out your cats

BTW i like the way that hood looks in your avatar

**67CamaroRSSS** · 12-10-2009, 07:48 AM

The "lack of back pressure" is an old wives tale.

If that were the case then why do top fuel cars have straight pipes?

I run QTP LT's without cats and the car runs just fine. I also deleted the rear O2's. Their only job is to tell the ECM how well the cats are working. The balance of my exhaust consists of an X-pipe that feeds 2 MagnaFlow mufflers (giving me a true dual exhaust setup) with all of it being dumped at the axle.

**justinmc978** · 12-10-2009, 08:11 AM

Originally Posted by 67CamaroRSSS

The "lack of back pressure" is an old wives tale.

If that were the case then why do top fuel cars have straight pipes?

I run QTP LT's without cats and the car runs just fine. I also deleted the rear O2's. Their only job is to tell the ECM how well the cats are working. The balance of my exhaust consists of an X-pipe that feeds 2 MagnaFlow mufflers (giving me a true dual exhaust setup) with all of it being dumped at the axle.

yeah go for headers&ORY you wont regret it, theres a header sticky in another part of this forum for all sorts of good info

and also yes cool avatar,

**mboodrx** · 12-11-2009, 07:56 AM

Id have to agree with the headers and ORY, I did this over a year ago, got rid of the cats... really happy with em

**st_cspeer** · 12-11-2009, 08:14 AM

As for me I went with High Flow cats, my speedshop scolded me said If i was going to do it I should have just dropped them altogher. So ORY!!!!

**gnomee** · 12-13-2009, 06:08 PM

Removing the cats will cause no issues at all. Other than that you need to put simulators on the rear 0/2 sensors or have them tuned out. Check out tunedbyfrost.com

Can anyone fill me in on WHY shops tell people about that back pressure thing? I have been of the opinion that is complete BS just used by the industry to make people think taking their cats off will make the car run bad. There could be some truth behind it on smaller engines maybe?

***SMWS6TA*** · 12-15-2009, 12:03 PM

This is after Pacesetter LT (No EGR) and TS&P ORY installed.

Removed the Cats. After 3 weeks had to replaced the muffler you hear in the vid. I blew all the baffles. Now have a Magnaflow (Sounds Nice). When it quits raining I'll get another vid.

View Video on FQuick

***SMWS6TA*** · 12-15-2009, 12:15 PM

Originally Posted by gnomee

Removing the cats will cause no issues at all. Other than that you need to put simulators on the rear 0/2 sensors or have them tuned out. Check out tunedbyfrost.com

Can anyone fill me in on WHY shops tell people about that back pressure thing? I have been of the opinion that is complete BS just used by the industry to make people think taking their cats off will make the car run bad. There could be some truth behind it on smaller engines maybe?

So they can justify selling you the CATS in states where emissions are not an issue. Had a shop tell me my car wouldn't run because it would not have the proper pressure to close the valves which would let to detonation in the cylinder. Told him your an idiot, walked out.

**gnomee** · 12-15-2009, 12:44 PM

LOL... So one Idiot made that up and it has spread like wild fire to all the chain muffler shops to boost sales! That just shows you how well BS travels.

**kool-aide** · 12-16-2009, 07:54 AM

here is some food for thought

big brother trying to keep you down, lol... it's not always the long arm of the state law you need to worry about.

http://www.epa.gov/otaq/cert/factshts/catcvrts.pdf

http://www.epa.gov/oms/regs/fuels/cff/memo-1a.txt

i think the key item to research is look up the EPA clean air act. I'm not trying to frighten any one, but so many people ask the same cat question, is it legal, can I take them off, blah. The bottom line is research your federal laws then your state laws.

I once remember some kind of paper work dealers used to have you sign when you bought and sold a car. They used to present something indicating the car emissions wasn't tampered. I can't remember the details. It has been too long, and when we bought the 02 z28. I don't remember them showing us the paper work at the time.

just my thoughts. personally i am in the 8 and 80k club, so... i don't foresee dumping a large chunk of cash into OEM cats,

, if they go on me.