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Topic: New exhaust system 81

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


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New exhaust system 81 (1/10)
 10/10/20 9:28am
TTJR 81
Former Member

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Bay City, MI - USA

Vette(s):
1981 white coupe, red interior, also had a 1971 , 1985, 2011 and 2015


Joined: 9/29/2020
Posts: 28

Want to replace the original system on my 81, very rusty and too quiet. I see Magnaflow  makes a complete bolt on with pipes, converter and mufflers. Does the air, smog pipe reconnect as well? Looking for more sound and would like to keep motor stock otherwise. Thanks! 

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Re: New exhaust system 81 (2/10)
 10/10/20 1:37pm
johnu
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Scottsdale, AZ - USA

Vette(s):
1981 Corvette Two-Tone Claret color, 4 spd, C7 Vert


Joined: 5/23/2007
Posts: 616

Not sure on that one.  I purchased a bolt on replacement "free flowing" cat years ago.  Got a little more rumble without messing with the original system.  I had to buy some heat resistant gray converter tubing $$ to complete the hookup.



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Re: New exhaust system 81 (3/10)
 10/10/20 2:13pm
manchestersharkLifetime Member
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Equinunk, PA - USA

Vette(s):
1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


Joined: 10/31/2007
Posts: 2434

Will it pass State Inspection without the Cat? If so, Just put a regular performance system on and enjoy it. 



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Re: New exhaust system 81 (4/10)
 10/10/20 3:11pm
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 888

Assuming you are keeping the original exhaust manifolds and an OEM equivalent converter, then all the emissions stuff should hook right back up.

If your state does not require a converter then I would go with the factory side exhaust as it's an easy way to do it plus it has very nice sound.



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Re: New exhaust system 81 (5/10)
 10/11/20 4:30pm
TTJR 81
Former Member

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Bay City, MI - USA

Vette(s):
1981 white coupe, red interior, also had a 1971 , 1985, 2011 and 2015


Joined: 9/29/2020
Posts: 28

So, if I don’t go with converter /stock setup what happens to the air pump smog pipe that would go to the converter? Would my computer know the difference 

Re: New exhaust system 81 (6/10)
 10/12/20 12:05pm
NorskyLifetime Member
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Burke, VT - USA

Vette(s):
SOLD - "The Toy" - '70 Convertible
SOLD - "The Beast" - '90 ZR-1 (#682)
SOLD - "Betty" - '28 Ford Model A Tudor
Still have - "BLKBRRD" - '78 Pontiac Trans Am


Joined: 1/23/2002
Posts: 7228

I've been told if a converter is removed from the exhaust system the air pump and its associated pumping can go away.  I can't say for sure but would think the computer would need to be reprogrammed to not look for input from the O2 sensor(s). 



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Re: New exhaust system 81 (7/10)
 8/30/22 2:21am
Dane2009
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Oklahoma City, OK - USA

Vette(s):
1977 l48 Classic White T-Top


Joined: 7/19/2022
Posts: 1

Did you like the result? I have a bone stock ‘77, l48, 350. It’s all original. Before changing exhaust (because it’s just too quiet on top of slow) I was contemplating cutting the cat off and replacing with bypass tube. I figured it would sound better… does it?

I don’t want to modify it anywhere but I gotta have it sound better…



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Re: New exhaust system 81 (8/10)
 8/30/22 5:55pm
F4GaryGold Member
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Grapevine, TX - USA

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


Joined: 8/26/2006
Posts: 1439

Dane2009 said:

Did you like the result? I have a bone stock ‘77, l48, 350. It’s all original. Before changing exhaust (because it’s just too quiet on top of slow) I was contemplating cutting the cat off and replacing with bypass tube. I figured it would sound better… does it?

I don’t want to modify it anywhere but I gotta have it sound better…


Why not just go with true duals and no cats?



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Re: New exhaust system 81 (9/10)
 8/30/22 5:56pm
F4GaryGold Member
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Grapevine, TX - USA

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


Joined: 8/26/2006
Posts: 1439

Norsky said:

I've been told if a converter is removed from the exhaust system the air pump and its associated pumping can go away.  I can't say for sure but would think the computer would need to be reprogrammed to not look for input from the O2 sensor(s). 


I would think on an 81 there is no after cat O2 sensor.  So just use the stock sensor in the stock location.



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Re: New exhaust system 81 (10/10)
 9/1/22 1:04pm
DroseLifetime Member
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Solon, OH - USA

Vette(s):
1981


Joined: 10/14/2015
Posts: 37

I have an 1981 vette and the member that responded mentioning that there is no after cat sensor is correct, there is none.  I have removed all smog/ air system and the car runs well without it.  I just emptied the cat of its contents.  Enjoy your ride

Drose



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