Deleting the Catalytic Converter

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Mango

Full Access Member
Joined
Dec 22, 2021
Posts
216
Reaction score
165
Location
JacksonWyoming
First Name
Gil
Truck Year
1989
Truck Model
1500
Engine Size
350
Hey All
I still have the original Cat on my 89 Burb 350 188.000 miles what happens if I take it off? Back pressure issues? MILPG? No Emissions in Wyoming

Thanks
 

CalSgt

Full Access Member
Joined
Oct 3, 2021
Posts
1,705
Reaction score
3,777
Location
CA
First Name
Casey
Truck Year
1980
Truck Model
Chevy K-10 Custom Deluxe
Engine Size
350
Theres no O2 sensor after the cat, won't cause any issue to remove it. You could also probably get in there & chip out the inside rather than cutting it out.

Is it busted? Rattling? Plugged up?

If you can pull a grade at full throttle it's not plugged.

I say leave it alone unless its busted or plugged up. Exhaust fumes are so much more tolerable with a working cat, especially when stopped idling in a drive through or stop light.
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
4,198
Reaction score
8,043
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
Scroll down a few lines on this forum and read the thread "Bringing the cat back.... enough is enough".
 

Radiohead

That guy on the Columbia
Joined
Mar 17, 2022
Posts
2,487
Reaction score
8,116
Location
Low Earth Orbit where it's safer
First Name
Eric
Truck Year
MCMLXXIX
Truck Model
C-20 Silverado Camper Special
Engine Size
454 crazy cubes, or 7.4 luscious litres
Hey All
I still have the original Cat on my 89 Burb 350 188.000 miles what happens if I take it off? Back pressure issues? MILPG? No Emissions in Wyoming

Thanks
What happens? You stink like unburned hydrocarbons. Your eyes water and it smells like 1972 all over again.

If it's not broken, don't "fix" it.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,449
Reaction score
28,372
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Imho, the factory cats still used on the GM trucks in '89 are all "broken". They are the restrictive, pellet type.

Cut that garbage off of there and put a modern type of cat in it's place. Best of both worlds, no power robbing and a cleaner exhaust.
 

BRetty

Full Access Member
Joined
Jul 16, 2020
Posts
931
Reaction score
2,623
Location
Los Angeles
First Name
Franklin
Truck Year
1973
Truck Model
c10
Engine Size
350
I'm thinking of "stealing" my own catalytic converters. I drive a '73 in California, no idea why the PO had cats on it, I have dark suspicions I won't air in a public forum.

My Exhaust is a F***ing mess, has broken on the highway causing fountains of sparks, the worst welding I have ever seen. I have almost all the parts now to replace it,, just no lift.

To be Continued......
 

mibars

Full Access Member
Joined
May 13, 2023
Posts
269
Reaction score
444
Location
Nadarzyn, Poland
First Name
Michal
Truck Year
1990
Truck Model
Suburban V1500
Engine Size
350 TBI
It will smell bad, give headaches to some but will untap a bit of power. I'd put a universal metal core cat instead. I used a Magnaflow cat converter in all my cars, worked well in 240 HP oil burning Honda, cutting all the smell and most of the smoke with no noticeable effect on power.
 

BRetty

Full Access Member
Joined
Jul 16, 2020
Posts
931
Reaction score
2,623
Location
Los Angeles
First Name
Franklin
Truck Year
1973
Truck Model
c10
Engine Size
350
I rejoice in the fact I could run straight headers with no mufflers at all and it would still be legal in KaliforniaStan. I know nothing about exhaust work, but my current plan is:

Replace crappy '83 exhaust manifolds with Doug Thorley Tri-y headers I got off CList
Headers --> 2.5" bolt-on header/reducers
Reducers --> 12" 2.5"dia flex pipes
Flex pipes --> 2.5" Summit Racing X-pipe assembly
X-pipe-assembly --> 2.5"/2.25" reducer(s)
Reducers --> existing 2.25" generic mufflers and existing tailpipes

I have all sorts of exhaust leaks and horrible noises coming from under my truck. I need to replace the exhaust and at least this will eliminate some potential sources of noise so I can know if my driveshaft is farked.

B
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
4,198
Reaction score
8,043
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
I rejoice in the fact I could run straight headers with no mufflers at all and it would still be legal in KaliforniaStan. I know nothing about exhaust work, but my current plan is:

Replace crappy '83 exhaust manifolds with Doug Thorley Tri-y headers I got off CList
Headers --> 2.5" bolt-on header/reducers
Reducers --> 12" 2.5"dia flex pipes
Flex pipes --> 2.5" Summit Racing X-pipe assembly
X-pipe-assembly --> 2.5"/2.25" reducer(s)
Reducers --> existing 2.25" generic mufflers and existing tailpipes

I have all sorts of exhaust leaks and horrible noises coming from under my truck. I need to replace the exhaust and at least this will eliminate some potential sources of noise so I can know if my driveshaft is farked.

B
Well then rejoice and get r done.
 

Strick

Full Access Member
Joined
Nov 25, 2020
Posts
1,362
Reaction score
3,330
Location
Dunn, NC
First Name
Harold
Truck Year
1979
Truck Model
C20 Crew
Engine Size
350
With all the Tamper Laws & Federal Mandates associated with converters, I wouldn't post ANY intention or mention of what plans I had for it. ICE engines ran for close to 100 years without them...so...

Strickland
 

Rusty Nail

Full Access Member
Joined
Jan 29, 2015
Posts
10,041
Reaction score
10,135
Location
the other side of the internet
First Name
Rusty
Truck Year
1977
Truck Model
C20
Engine Size
350sbc
What will happen? It WILL stink and make you nauseous, you will hate it. Huge turnoff for anyone near your truck, needless to say it's 100% illegal. Certainly will NOT turn your Suburban into a racing truck..:nono:

Again, you will hate it.

A new one is a good idea, technology has come a long way. You can buy aftermarket from your muffler shop OR
Jeg's sells a Flowmaster brand for a measly $150.

@ www.jegs.com
You must be registered for see images attach


Did I mention the part about you would hate it? It's truuuuuuuuuue!
Truuuuuuuuuuuuue!!
 
Last edited:

WFO

Full Access Member
Joined
Jan 6, 2017
Posts
3,696
Reaction score
5,052
Location
Texas Panhandle
First Name
Dan
Truck Year
1986
Truck Model
K20
Engine Size
350
What will happen? It WILL stink and make you nauseous, you will hate it. Huge turnoff for anyone near your truck, needless to say it's 100% illegal. Certainly will NOT turn your Suburban into a racing truck..:nono:

Again, you will hate it.

A new one is a good idea, technology has come a long way. You can buy aftermarket from your muffler shop OR
Jeg's sells a Flowmaster brand for a measly $150.

@ www.jegs.com
You must be registered for see images attach


Did I mention the part about you would hate it? It's truuuuuuuuuue!
Truuuuuuuuuuuuue!!
Mine is an 86 with the C6P option, so it came from the factory without cats, even has the large fuel fill opening for leaded gas.
I don't hate it. People around it don't hate it, and no one has gotten gotten nauseous.
Same thing with my 69 Chevelle.
 

mlsceo

Full Access Member
Joined
Dec 29, 2022
Posts
407
Reaction score
1,222
Location
Kingsburg California
First Name
Manuel
Truck Year
1977
Truck Model
c10
Engine Size
350
Mine is a 77 long bed. Though I still have to do smog checks it came stock without a cat due to the 6050 GVWR. I went with dual 2 1/2" exhaust with 40 series Flowmasters, H pipe, and side exits. Doesn't stink or offend anyone and sounds amazing.
 

84C20HD

Junior Member
Joined
Jun 28, 2023
Posts
15
Reaction score
9
Location
MANAHAWKIN, NJ
First Name
CHARLIE
Truck Year
1984
Truck Model
C20
Engine Size
305
I own two Canadian built 1984 C20 and a C30. The C20 came with a convertor and the C30 without. When I get around to getting the C30 on the road it will have a convertor on it. NOBODY likes driving behind a SKUNK !
 

Rusty Nail

Full Access Member
Joined
Jan 29, 2015
Posts
10,041
Reaction score
10,135
Location
the other side of the internet
First Name
Rusty
Truck Year
1977
Truck Model
C20
Engine Size
350sbc
Oh boy oh boy! Hot rod racing Suburban here we come!!

xc_hide_links_from_guests_guests_error_hide_media
 
Last edited:

Forum statistics

Threads
44,201
Posts
951,543
Members
36,334
Latest member
jayeatwrld
Top