Catalytic Converter

LordKevin · 01-31-2017, 07:04 PM

Sorry I'm new to this..what would be the difference from removing this and what could be possible downsides? Why would one want to remove them?

Mrmandmman · 01-31-2017, 07:13 PM

Increased pollution. Might void the warranty. Can't pass emissions. Might smell like rotten eggs. Get a race cat if you want to swap it.

Ian SS · 01-31-2017, 07:15 PM

There are 4 total. 2 running off each header (primary) and another 2 about 2 feet down (secondary).

People typically remove the 2 secondary cats because it sounds better at open throttle and doesn't throw a code. Also pretty cheap, and can typically get away with inspections as some might just think they are resonators.

Removing the primary cats are more involved and will throw a check engine light, but you could pick up some small HP gains (at the expense of being really loud and illegal).

enzia35 · 01-31-2017, 07:19 PM

Just remove the secondary cats if anything. I'm not a peace Nik hippie, but I'm not going to burn tires in my yard just for fun either.

I'll burn them on the strip!!!

ron scubadiver · 02-01-2017, 01:37 AM

I really feel negative about folks removing their catalytic converters as a mod, especially when there are high flow converters available.

Yellow6thGen · 02-01-2017, 06:44 AM

You have to remove the rear two all the time if you plan on changing your exhaust... I have not seen a performance exhaust with them installed or wanted? Just my .02. I bought thenKooks longtubes with the Cats though!

Quote:

Originally Posted by ron scubadiver

I really feel negative about folks removing their catalytic converters as a mod, especially when there are high flow converters available.

cmeJATT · 02-01-2017, 09:44 AM

just remove the secondary cat... NO CEL no problems...

oldman · 02-01-2017, 11:52 AM

IMO, front cat deletes move the 02 behind the rear cats and spacers = no or very intermittent cel (self clearing). IMO the front cats are WAY more restrictive at 2.1 ID" with major small sharp bends vs 2.65" ID of the rears straight through and um cooler exhaust... you know the gas law and all.

Waxenate · 04-09-2022, 06:26 PM

I was trying to be good after I had my 2019 SS built. Ended up blowing the high flow cars out. One completely and dislodged the other. There are HP limits on them so make sure to check that. Keep cats if you can.

Daily1LE · 04-11-2022, 05:43 PM

Quote:

Originally Posted by LordKevin

Sorry I'm new to this..what would be the difference from removing this and what could be possible downsides? Why would one want to remove them?

People remove cats because it's a cheap way to make your car louder and the theory is it will add some horsepower.

Some downsides:
- Illegal to remove
- Will trigger check engine light
- Increased air pollution
- Increased noise pollution (most will say this is as an upside)
- Won't pass emissions
- Smell
- Possible warranty issues

As a few others stated before me, most people that remove cats are removing just the secondary cats. Another option is replacing the exhaust and adding some high flow cats. Many companies that sell exhaust for our cars will offer systems with high flow cats. It does cost more and I think this is ultimately why most people do not get cats when ordering new exhaust.

synolimit · 04-11-2022, 10:09 PM

Quote:

Originally Posted by Daily1LE

People remove cats because it's a cheap way to make your car louder and the theory is it will add some horsepower.

Some downsides:
- Illegal to remove
- Will trigger check engine light
- Increased air pollution
- Increased noise pollution (most will say this is as an upside)
- Won't pass emissions
- Smell
- Possible warranty issues

As a few others stated before me, most people that remove cats are removing just the secondary cats. Another option is replacing the exhaust and adding some high flow cats. Many companies that sell exhaust for our cars will offer systems with high flow cats. It does cost more and I think this is ultimately why most people do not get cats when ordering new exhaust.

secondaries wont trigger a CEL and smells subjective. i think it smells way better than what catted exhaust smells like.

arpad_m · 04-11-2022, 11:26 PM

Quote:

Originally Posted by synolimit

secondaries wont trigger a CEL and smells subjective. i think it smells way better than what catted exhaust smells like.

...now what really smells better and pollutes less after a secondary cat delete is ethanol

However, this is another one of those spectacular thread resurrections after 5 years

I'm sure OP is long gone or at least won't care anymore, having received a bunch of answers.

ctrlz · 04-12-2022, 10:56 AM

Quote:

Originally Posted by ron scubadiver

I really feel negative about folks removing their catalytic converters as a mod, especially when there are high flow converters available.

Probably not a worthwhile idea for 99.9% of the people who do it. Even if it only costs $100 it is not worth the risk of somebody doing unintentional damage by lifting the vehicle or cutting the pipe.
This will not add power.
http://speed.academy/how-catalytic-converters-work/

Ventmaster · 04-12-2022, 10:11 PM

+1 on the leave'em alone Kev. Negligible power increase. Significant noise increase if you remove both with a new raw gas smell that will follow you wherever you go. That means anyone driving behind you will know.

Florida does not currently monitor emissions but it is regulated by the Feds/EPA and considered it a viloation of the Clean Air Act (you can check out the potential results of that violation yourself, but I'll bet you will not find any shop willing to tamper with existing cats), which celebrated its 50th anniversary in 2020 and believe me if the Feds decide monitoring is needed it will happen.

01-31-2017, 07:04 PM	#1
LordKevin Drives: 2016 Camaro 2ss Red Hot Join Date: Jan 2016 Location: florida Posts: 135	Catalytic Converter Sorry I'm new to this..what would be the difference from removing this and what could be possible downsides? Why would one want to remove them?

01-31-2017, 07:15 PM	#3
Ian SS Drives: 2016 1SS, 2017 JKU Wrangler Join Date: Mar 2016 Location: San Diego Posts: 876 View My Garage	There are 4 total. 2 running off each header (primary) and another 2 about 2 feet down (secondary). People typically remove the 2 secondary cats because it sounds better at open throttle and doesn't throw a code. Also pretty cheap, and can typically get away with inspections as some might just think they are resonators. Removing the primary cats are more involved and will throw a check engine light, but you could pick up some small HP gains (at the expense of being really loud and illegal). __________________ SLO 1SS - sold 1SS MRC NPP 6MT 2018 Ram Rebel 4x4 5.7

01-31-2017, 07:19 PM	#4
enzia35 Drives: '16 Garnet Red 1SS Join Date: Mar 2014 Location: College Station, TX Posts: 3,449	Just remove the secondary cats if anything. I'm not a peace Nik hippie, but I'm not going to burn tires in my yard just for fun either. I'll burn them on the strip!!! __________________ '16 Camaro 1SS '18 Miata GT Gone: '01 Camaro, '14 Camaro, '90 Miata

02-01-2017, 11:52 AM	#8
oldman Drives: SS 6 speed of course Join Date: Jan 2016 Location: Hilo, HI Posts: 4,339	IMO, front cat deletes move the 02 behind the rear cats and spacers = no or very intermittent cel (self clearing). IMO the front cats are WAY more restrictive at 2.1 ID" with major small sharp bends vs 2.65" ID of the rears straight through and um cooler exhaust... you know the gas law and all. __________________ Forged short block, large duration sub .600 lift Cam Motion cam, 7200 RPM fuel cut, Pray Ported Heads, 3.85 pulley D1X, stage II intercooler, DSX secondary low side, DSX E85 sensor, Lingenfelter big bore 2.0 pump, ported front cats, 60608 Borla, LT4 injectors, ZL1 1LE driveshaft and Katech ported TB, ported MSD intake, BTR valvetrain, ARP studs, ProFlow valves, PS4 tires.

04-09-2022, 06:26 PM	#9
Waxenate 2019 2SS Drives: 2019 SS Join Date: Nov 2019 Location: Summerville SC Posts: 14	I was trying to be good after I had my 2019 SS built. Ended up blowing the high flow cars out. One completely and dislodged the other. There are HP limits on them so make sure to check that. Keep cats if you can. __________________ 2019 2SS Bored and stroked to 416ci Pro charger Stage 2 intercooler Crenshaw tune Custom ported and polished heads Kooks longtube headers Borla 3” cat back S-Type Biking 4 way adjustable coil overs Multiple BMR upgrades

01-31-2017, 07:13 PM	#2
Mrmandmman Drives: BMW Join Date: Jan 2017 Location: Fort Collins, CO Posts: 12	Increased pollution. Might void the warranty. Can't pass emissions. Might smell like rotten eggs. Get a race cat if you want to swap it.

02-01-2017, 01:37 AM	#5
ron scubadiver Drives: 2017 2SS Hyper Blue Join Date: Dec 2016 Location: Houston TX Posts: 550	I really feel negative about folks removing their catalytic converters as a mod, especially when there are high flow converters available.

02-01-2017, 09:44 AM	#7
cmeJATT Drives: CAMARO Join Date: Jan 2017 Location: USA Posts: 1,392	just remove the secondary cat... NO CEL no problems...

04-12-2022, 10:11 PM	#14
Ventmaster Drives: 2017 1SS 6spd Join Date: Jan 2011 Location: Utah Posts: 3,022	+1 on the leave'em alone Kev. Negligible power increase. Significant noise increase if you remove both with a new raw gas smell that will follow you wherever you go. That means anyone driving behind you will know. Florida does not currently monitor emissions but it is regulated by the Feds/EPA and considered it a viloation of the Clean Air Act (you can check out the potential results of that violation yourself, but I'll bet you will not find any shop willing to tamper with existing cats), which celebrated its 50th anniversary in 2020 and believe me if the Feds decide monitoring is needed it will happen.

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