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call the fire department! chould I keep cat?

Forum: C3 HVAC, Fuel, Emissions, and Exhaust

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call the fire department! chould I keep cat?

Posted: 12/6/07 1:39pmMessage 1 of 10
f
Former Member
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Fresno, TX - USA
Joined: 1/15/2007
Posts: 240
Vette(s): 1980 corvette

I have a hi flow cat on my 80. it has headers and three inch pipe going to the cat and to the mufflers. I was doing test runs on my street and the cat burned the carpet under passenger seat. If I cut the cat off and ran straight pipe will I still get the same torque? I want something that does not get hot. any  sugg? oh I also have a very small cam same 350 small block eldlebrock carb.

  
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call the fire department! chould I keep cat?

Posted: 12/6/07 1:46pmMessage 2 of 10
P
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Shenandoah, PA - USA
Joined: 10/18/2006
Posts: 328
Vette(s): 1982 Chevrolet Corvette
A cat shouldn't get hot enough to cause interior damage unless it was blocked, bad, or installed improperly.  That said, runnning a straight pipe shouldn't create a noticeable loss of backpressure or torque.  It is illegal, however, and if there are emissions inspections where you live, you'll definitely need one. 
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call the fire department! chould I keep cat?

Posted: 12/6/07 1:48pmMessage 3 of 10
f
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Fresno, TX - USA
Joined: 1/15/2007
Posts: 240
Vette(s): 1980 corvette
No emissons here. I just dont want to loos torque
  
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call the fire department! chould I keep cat?

Posted: 12/6/07 2:51pmMessage 4 of 10
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Shenandoah, PA - USA
Joined: 10/18/2006
Posts: 328
Vette(s): 1982 Chevrolet Corvette
I doubt you'll notice any decrease in performance with a straight pipe.
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call the fire department! chould I keep cat?

Posted: 12/6/07 2:57pmMessage 5 of 10
f
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Fresno, TX - USA
Joined: 1/15/2007
Posts: 240
Vette(s): 1980 corvette
sounds good psu
  
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call the fire department! chould I keep cat?

Posted: 12/6/07 3:22pmMessage 6 of 10
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WEST SENECA, NY - USA
Joined: 12/3/2001
Posts: 2381
Vette(s): 1981 Blue Ice Met. w/pearl ghost flames TKO500 5speed. LS1 Swap 3.45 Dana 44.
You may want to check to see if your carburetor is running to rich. A rich condition will overheat the catalytic converter. Also to much spark timing will cause the exhaust temps to rise excessively.
 I other words..an engine in proper tune should not affect the cat operation.
 
Let me ask you this...what kind of test were you doing out on the street?


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call the fire department! chould I keep cat?

Posted: 12/7/07 10:24amMessage 7 of 10
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Victor, NY - USA
Joined: 7/12/2004
Posts: 6842
Vette(s): 2004 Commemorative Edition Coupe, Auto w/HUD. 13K miles in 2015. Sold 1982 Red Coupe
Is there a heat shield between the cat and the underside?
 
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call the fire department! chould I keep cat?

Posted: 12/7/07 11:09amMessage 8 of 10
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 22715
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
I wonder that meself...with the metal floor pan, and no heat shield, I would imagine it do get hot there!

A rich condition, as Darryl pointed out, will overheat the cat, as well as a problem with the AIR system...perhaps the AIR ain't working?

Doin burn-outs, were ya?

When they were testing the cat systems way back when, before the '75 cars came out, Zora actually burned a car to the ground from overheating the cat! He was coasting down a hill, engine running, and the raw fuel in the cat ignited...ooooops!

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call the fire department! chould I keep cat?

Posted: 12/7/07 11:09amMessage 9 of 10
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Klamath Falls, OR - USA
Joined: 2/1/2006
Posts: 1062
Vette(s): 74 coupe 4 speed 350, 54K actual miles, all original; paint, interior, engine, split bumper. #'s match. 2nd owner, no stress cracks.
If it was me, I would eliminate the cat.  To me the less "junk" constricting the exhaust the better. But would do so only if you don't have to smog.  What about if and when the vehicle changes ownership? Here in CA, sometimes you have to smog with the new owner.  By the way, real good looking vette you have from pic.Thumbs%20Up

Steve, Lifetime Member #129

74 coupe 4 speed 350, 54K actual miles,
all original; paint, interior, engine,
split  bumper. #'s match. 2nd owner, no stress cracks.
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call the fire department! chould I keep cat?

Posted: 12/7/07 11:32amMessage 10 of 10
f
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Fresno, TX - USA
Joined: 1/15/2007
Posts: 240
Vette(s): 1980 corvette
I was just running up and down the street. I was not spinning the tires. I have no heat shield. So off it will goooooooooooooo 
  
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