Home page
SPONSOR AD

Support our Vendors!  |  Advertise Here

Topic: Catalytic Converter Removal??

in Forum: C3 Fuel, Emission Control, and Exhaust Systems


Already a Member?
Login
Not yet a Member?
Register for Free!

Catalytic Converter Removal?? (1/24)
 3/31/07 9:14pm
Blue-79
Former Member

Send Private Message

Ashburn, VA - USA

Vette(s):
1979 L-48 Coupe, 4-speed, Blue/Blue, in family 20 years


Joined: 3/16/2007
Posts: 48

Did you hear about the lawyer who discovered that a client had inadvertantly given him TWO $100 bills to setlle a $100 debt??
 
The attorney struggled with the moral question; "Should I tell my partner??"
 
My moral question relates to the possible removal of the cat converter from my '79.
 
Now first let me say that I am very GREEN. I recycle everything. But I question if a converter that is nearly 30 years old does anything. And I know they run very hot, and if clogged cause performance problems and may add to pollution.
 
My question to the jury then, what effect would removing the converter have?
 
I am thinking of going to side pipes.
Our Sponsors help support C3VR
Catalytic Converter Removal?? (2/24)
 3/31/07 9:20pm
Gunslinger
Former Member

Send Private Message

Frederick, MD - USA

Vette(s):
1969 convertible L71 427/435 4-speed black interior


Joined: 9/8/2003
Posts: 3398

Remove the converter if your state doesn't perform emissions tests anymore after the car reaches a certain age...usually 25 years, but not all states allow it.

If your converter is partially or fully clogged, it will definitely run better. Even if it is operating OK, remove it and install a true dual exhaust system (or sidepipes) and the lessened back pressure will free up some horsepower and the car will run better...maybe cooler. No converter also will lessen the heat under the floorboards.
Catalytic Converter Removal?? (3/24)
 4/1/07 9:22am
lukesvetteLifetime Member
Lifetime Member
Send Private Message

HOWELL, NJ - USA

Vette(s):
1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.


Joined: 5/18/2004
Posts: 6812

Emissions go out the window when the converter is removed. A tough decision for a GREEN preson.
 
Then again, as Gunslinger mentioned, it's like giving your motor a get out of jail free card...
 
However, there are more expensive routes, for example, upgrading to a high performance converter....Confused
Catalytic Converter Removal?? (4/24)
 4/1/07 9:36am
tuxblacrayLifetime Member
Lifetime Member
Send Private Message

Greensburg, IN - USA

Vette(s):
Previous: 1984 Silver / Charcoal Coupe, 1988 Maroon Coupe / 1989 Artic White Coupe / 2001 Speedway White Roadster / Present:1976 Stingray Black / Black, Auto, 350 slightly modified (355 hp) Luxor Wires Redline Tires. / 1989 Roadster Bright Red...


Joined: 9/24/2003
Posts: 5188

Headers ... Converter ... whatz that ??? Let me think... ya reckon the Harley guyz have converters on their bikes? NOT.... Take it off & rest your green mind. Let that car breath.

______________

Tuxblacray: She's Back In Black! Check out my pics @ My Link


(Click on image to see a bigger version)


Catalytic Converter Removal?? (5/24)
 4/1/07 4:49pm
Blue-79
Former Member

Send Private Message

Ashburn, VA - USA

Vette(s):
1979 L-48 Coupe, 4-speed, Blue/Blue, in family 20 years


Joined: 3/16/2007
Posts: 48

OK, Thanks to all.
 
VA does notrequire that I pass the emissions tests any longer. I only have to go through the safety inspection at this point.
Catalytic Converter Removal?? (6/24)
 4/5/07 9:44am
maintenance4
Former Member

Send Private Message

Tecumseh, MI - USA

Vette(s):
1980 all org. with 18000 act. miles dk claret with matching interior..Eagle alloys ..loaded..excellent cond.


Joined: 9/14/2003
Posts: 221

Year's ago, they use to sell a (test pipe) which replaced the converter. Wish I could get my hands on one now. Put one on my first 80 years ago, what a difference it made...
Catalytic Converter Removal?? (7/24)
 4/5/07 11:29am
crossfire1982
Former Member

Send Private Message

Cramerton, NC - USA

Vette(s):
black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion


Joined: 8/22/2006
Posts: 1094

Jerry, if you ever find a source for those test pipes for our cars, please post the supplier.  I can find them all over the net for the ricers, but not for any domestic cars.
Catalytic Converter Removal?? (8/24)
 4/5/07 12:40pm
dwright
Standard Member
Moderator
Send Private Message

Victor, NY - USA

Vette(s):
2004 Commemorative Edition Coupe, Auto w/HUD. 13K miles in 2015. Sold 1982 Red Coupe


Joined: 7/12/2004
Posts: 6833

[QUOTE=maintenance4]Year's ago, they use to sell a (test pipe) which replaced the converter. Wish I could get my hands on one now. Put one on my first 80 years ago, what a difference it made...[/QUOTE]
 
You will sometimes see these on e-bay.


______________
 
Save the Wave!
Support the National Corvette Museum   
Catalytic Converter Removal?? (9/24)
 4/5/07 2:00pm
PSU 98
Former Member

Send Private Message

Shenandoah, PA - USA

Vette(s):
1982 Chevrolet Corvette


Joined: 10/18/2006
Posts: 328

If you really wanted to run a straight pipe on your 'Vette I'm sure you could have the flanges cut off the stock coverter and TIG welded onto a section of stainless pipe.
Catalytic Converter Removal?? (10/24)
 4/5/07 5:10pm
767REPLifetime Member
Lifetime Member
Send Private Message

Joined: 3/31/2007
Posts: 293

I talked to my local muffler shop and (1977 l48 stock) he told me that any car that originally had a cat cannot be modified by a shop due to a 2500.00 federal fine. He ajso told me that factory cats were 48% resrictive and the new cats are 95%.He told me the sound and performance with new cats would be like no cats at all.Any ideas?

______________


(click to see a larger version)

Catalytic Converter Removal?? (11/24)
 4/5/07 5:13pm
mbarney
Former Member

Send Private Message

Davie, FL - USA

Vette(s):
1980 l48


Joined: 2/29/2004
Posts: 173

Catalytic Converter Removal?? (12/24)
 4/5/07 5:19pm
Gunslinger
Former Member

Send Private Message

Frederick, MD - USA

Vette(s):
1969 convertible L71 427/435 4-speed black interior


Joined: 9/8/2003
Posts: 3398

Modern, performance cats are very high flow. Look at Summit Racing or Jeg's...they carry high performance cats and they're not really expensive. Maybe some modifications to your exhaust since they're not application specific, but that's about all.
Catalytic Converter Removal?? (13/24)
 4/6/07 10:47am
Greg78SA
Former Member

Send Private Message

Saginaw, MI - USA

Vette(s):
1978 Silver Anniversary... Almost all original/correct L48 auto,59k miles, oyster.


Joined: 9/22/2006
Posts: 146

There's a hefty penalty (Fine and possible jail time) from the feds for  using a test pipe.  However, Nextag sells em as "cat con replacement units"  with  the caveat that they are not street legal.  My corvette shop guy says there is not much to be gained.  I poked around some more and got numbers between 3 and 5 hp as a gain.  AND the lack of a converter causes issues such as hesitation, etc.
 
 IMHO...Not worth it!
 
Greg
Catalytic Converter Removal?? (14/24)
 4/6/07 3:10pm
Greg78SA
Former Member

Send Private Message

Saginaw, MI - USA

Vette(s):
1978 Silver Anniversary... Almost all original/correct L48 auto,59k miles, oyster.


Joined: 9/22/2006
Posts: 146

Oh, and the corvette shop guy said he'd never seen a catalytic converter wear out...he's 52 yrs old.Smile
Catalytic Converter Removal?? (15/24)
 4/7/07 1:26am
Gale Banks 80Lifetime Member
Lifetime Member
Send Private Message


Vette(s):
1980 with a Banks Twin Turbo 1969 Convert Big Block 1996 Grand Sport Convert


Joined: 9/8/2005
Posts: 241

  I put a Test Pipe on My 80' way back when it was nearly New. Couldn't stand the Sound of it it makes for a Raspy Sound threw the Stock Mufflers. It might of Sounded a Bit Faster but that was all I gained so I put the Cat back on after a Week. Keep in Mind that a Corvette Comes from the Factory with 505 HP threw Cats these Days. The best is a True Dual Exhaust with Twin Cats Like every Vette has come with for the last 20 Years but You Cannot Buy it You will have to make it because of Legalitys. Keep in Mind Cats are just Like any other Exhaust Product Bigger is better. Richard....

______________
My Car...PIC 1     PIC 2
Catalytic Converter Removal?? (16/24)
 4/7/07 8:30am
maintenance4
Former Member

Send Private Message

Tecumseh, MI - USA

Vette(s):
1980 all org. with 18000 act. miles dk claret with matching interior..Eagle alloys ..loaded..excellent cond.


Joined: 9/14/2003
Posts: 221

The main reason I would like to eliminate the cat. is to cut down on the interior heat that comes from the converter. Even though I do have a/c, I like the wind blowing through what hair I have left. Thank's for the imput guys. Will consider my options on this one. Maybe I will go with dual exhaust...
Catalytic Converter Removal?? (17/24)
 4/7/07 5:59pm
Sarge81Lifetime Member
Lifetime Member
Send Private Message

WEST SENECA, NY - USA

Vette(s):
1981 Blue Ice Met. w/pearl ghost flames TKO500 5speed. LS1 Swap 3.45 Dana 44.


Joined: 12/3/2001
Posts: 2379

[QUOTE=maintenance4]Year's ago, they use to sell a (test pipe) which replaced the converter. Wish I could get my hands on one now. Put one on my first 80 years ago, what a difference it made...[/QUOTE]
 
PM sent.


______________

GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.
3.54 Dana 44
'69 "N11" Sidepipes
Borgeson Steering Box
Born 8/1981
Sequence #3975




Click here to see more pics of my Vette on CarDomain.


Lifetime Member #26
Catalytic Converter Removal?? (18/24)
 4/7/07 6:56pm
eddie20875Lifetime Member
Lifetime Member
Send Private Message

Lanoka Harbor, NJ - USA

Vette(s):
1975 metallic blue coupe with t-tops,L48, t/t steering, black leather interior. 1990 L98, white/red leather interior, auto,a/c


Joined: 12/21/2006
Posts: 828

[QUOTE=Greg78SA]Oh, and the corvette shop guy said he'd never seen a catalytic converter wear out...he's 52 yrs old.Smile[/QUOTE]

i understand corvettes are top notch cars but for him to state he never seen one go bad leaves me wondering. i am 52 and i have seen cats go bad not only on one of my cars but on other peoples cars as well. granted my car wasn't a corvette, it was a cadillac. after a lot of aggravation the dealer found it was the cat was bad. of course it wound up costing 600.00 thru the dealer to replace it once it was done the problem cleared up.

as i have headers on my vette there are no cats on my car and it doesn't sound bad. it has to me a great sound at idle like the power is waiting to be unleashed and cruising sounds great too.
eddie208752007-04-07 15:58:49

______________
LIFETIME MEMBER #97
THE DYNAMIC DUO


Catalytic Converter Removal?? (19/24)
 4/8/07 1:37pm
Autom8r
Former Member

Send Private Message

Old Hickory, TN - USA

Vette(s):
1978 L-82 Silver Anniversary hotrod. /////////////


Joined: 5/26/2003
Posts: 599

I have an '82 Chev pickup with a 305 4-bbl. It always got 13.5 MPG. I pulled the cat off and the mileage went up to 16.5 MPG. Can't say much for the performance, cause there never was any in the first place. It is registered in a county w/o smog tests....

My 'Vette has full length headers and a 2-1/2" true dual exhaust blowing out thru straight-through Walker welded Dyno-Max mufflers and the ZZ-4 sounds and runs perfect, with 20 MPG hwy.

I never have been a big fan of cats, steel and platinum or 4-legged.....

Dave
Catalytic Converter Removal?? (20/24)
 4/17/07 4:25pm
sfindlan
Former Member

Send Private Message

Badin Lake, NC - USA

Vette(s):
1979 Red L-48 Corvette with Doeskin interior, 3-speed automatic, 3.55 rear; 1986 L-98 Coupe, 4+3 Manual - Satin Black and Purple (SCCA TT/Hillclimb Car); 1993 White LT-1 Coupe, Black Interior, 6-speed


Joined: 4/21/2004
Posts: 101

I am 51 and can say that I have seen cats "wear" out by the internals coming loose, causing blockage. I have also found the internal mesh (on the monolithic ceramic types) clogged.  My solution is to use a large hammer drill to "clean" out the blockage and put the cat back in place.  If you don't like the sound - get new mufflers - many great sounding cars were built in the 60s/70s without cats.  I have always seen an increase in mileage and performance - even if it was only 1 or 2 mpg.



______________
C3: 1979 Corvette Coupe, Auto, L-48, Red/Doeskin (my wife's fave);
C4s: 1986 C4 coupe (SCCA road race car), satin black, 4+3, Z51 package, L-98;  & 1993 C4 coupe, white, 6-speed, LT-1.
Re: Catalytic Converter Removal?? (21/24)
 6/7/14 12:06pm
Joanne
Former Member

Send Private Message

Joined: 11/30/2006
Posts: 441

so many people here are having cats stolen off cars.

I had attest pipe  I fitted on a l200 truck, made a lot more power. don't know about mpg,just drove it harder.



______________
1979 Corvette
Re: Catalytic Converter Removal?? (22/24)
 6/7/14 12:59pm
F4GaryGold Member
Gold Member
Online Now! - Send Private Message

Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air.


Joined: 8/26/2006
Posts: 1406

Do it.  That mechanic was talking out of his muffler.  Wink

______________

   

Re: Catalytic Converter Removal?? (23/24)
 6/8/14 10:37am
nextdoor76
Former Member

Send Private Message

Kimberling City, MO - USA

Vette(s):
1976 Stingray


Joined: 12/2/2012
Posts: 49

I have a friend with an 03 corolla with bad cat. and the cost to replace was over $1000, of course it has 270,000 miles one it. And I had a ford ranger that went bad about 140,000..so yes they do go bad, mine had to replaced....and the corolla is just blow out, so only problem is the check engine light stays one.


 



______________
Re: Catalytic Converter Removal?? (24/24)
 6/8/14 6:21pm
CCasey
Former Member

Send Private Message

New Albany, OH - USA

Vette(s):
1980 Coupe / Snowcrest White / L48, 350 / Comp Cam / Edelbrock Heads / Cyclone Intake / Holley Carb / Holley Fuel Pump / Patriot Headers / Dual Exhaust / Magnaflow Mufflers / 1964 Coupe / Riverside Red / L76, 327, 365hp


Joined: 8/17/2010
Posts: 173

I took the cat off my '80 about 3 years ago and replaced it with tight-tuck headers, 2 1/2 inch aluminum exhaust, and Magnaflow mufflers.  Absolutely helped performance but I also installed a performance cam, dual plane intake, and 770-cfm Holley carb.
 
Also, in Ohio, some cars are permanely exempted from ever having an emmisions check.
 

Several types of vehicles are PERMANENTLY EXEMPT from the E-Check test requirement and do not need a visual inspection. A complete list with a detailed explanation may be found in Ohio Administrative Code, Section 3745-26-12(c). It is not necessary for vehicle owners that are permanently exempt to be issued an exemption certificate. The most common types are listed below.

  1. Vehicles more than 25 years old, as determined by vehicle model year;
  2. Commercial vehicles weighing more than 10,000 pounds gross vehicle weight rating;
  3. Historical and collector's vehicles - contact Ohio BMV for details;
  4. Parade and exhibition vehicles - contact Ohio BMV for details;
  5. Motorcycles, recreational vehicles and motor homes - contact Ohio BMV for details;

Since my car is older than 25 years and I have Collector plates, I qualify for permanent exemption under numbers 1 and 3.



______________
Chuck

Our Sponsors help support C3VR