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gutting the cats

W

wookiebear

Guest
Has anyone attempted to remove the interior of the catalitic converters? Any feedback would be appreciated.
 

jsinga

Well-known member
Joined
Nov 23, 2001
Messages
280
Location
Savannah, GA, USA
Corvette
87 Silver Coupe Way over 200k miles
On my 87, it has pre cats up front and one main cat . The main just use a long staight pipe and bang the guts out. The front pre cats you have to bend a piece of 1/2 inch pipe to get around the corner and bust out the bricks.
If the cats aren't plugged up it isn't worth the trouble IMO.

JS
 

BigRed

Well-known member
Joined
May 23, 2001
Messages
948
Location
Edmonton
Corvette
1985 Bright Red Rocket
Take a 2x4 and line it up on the unit. Now take you 32Oz hammer and assertavley beat the living hell outta it ( :t ).

Now like a Martini not shaken STIR ( Shake the unit out till you hear no more Rattle's)

Ive done this for some British Columiba cars here in Canada B.C is your California to some degree and Alberta (right beside) is No hold barred......


Guess where I live

:D :D :D :D :D
 

Ken

Gone but not forgotten
Joined
Jan 30, 2001
Messages
8,236
Location
Hermosa Beach, CA
Corvette
1987 Z51 Silver Coupe
Ok Wookie, here it is:

As for gutting the cat, I have had no personal experience, but this was reported here in the thread: Looking for muffler suggestions!, as a method of performing the required surgery:

First get your vette on a lift. Remove both cats from the exhaust maniold. Get the cats on the ground. Make sure the exhaust is cool! Find yourself a stick of somesort about the size of a broom handle. You'll see inside the cats a honeycomb like substance. That I believe is called platinum cataylst. You need to break all that up and remove it from the converters. Reinstall. No other changes need be made O2 sensor ect.


It's a rather primitive method to use, but I guess if you're looking to save a few bucks it'd be worth it. Myself, I am thinking of installing a Random Technology (or something similar) high -flow converter when I get the new engine in. I may even make up a piece of straight pipe and do a dyno comparison with and without the converter in place.

Good luck.

_ken :w
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
wookiebear,


You have three cats on that 96.

Be advised that you MUST replace the rear O2 sensors with the custom fake signal units to mimic the standard feed of a hot cat back to the computer. Otherwise you will get a check engine light, and a loss of power instead of increase.

I think only the 95-96 models are equiped with the extra set of O2 sensors.

Otherwise, the pre-cats are hard to get to from the inside. I have heard the best method is to remove the Y-pipe and exhaust, cut the heat shield, cut a door in the upper side of the precat, then clean it out anyway you can. Then, weld it back closed and reinstall the heat shield.

The center cat is best cleaned out with a drill extension and a 1" or 1 1/2" wood boring bit. You can make about 10 or 12 drills up the gut from either direction, then use a long pry bar, flat head screw driver etc. to chip out the remaining portion.

Now for the downside. Unless you are running race gas and other additives that the CAT won't tollerate, you really should not expect to get much more performance out of whacking the CATS. The truth is, they are street friendly to the LT4 engine and allow it to better build low end torque and keep the noise level down.
 
V

vetsvette

Guest
3 cats?

69- The '96 Vette has only two cats and no Y-pipe. You can install the O2 simulators or not. If you don't it will set a check engine light but will not effect the tuning. The second set if sensors is to check the efficiency of the cats. I replaced my cats with straight pipes and can really tell the difference. If you don't want to spring for the simulators right away just place a small piece of electricians tape over the offending light on the DIC.:_rock
Oh yeah, I installed a set of hooker headers at the same time so I'm sure that helped a little.
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
Whitey,

You are right, the center deal is a resonator on the newer ones.

My good friend had a 96 with the LT4 engine a couple of years ago. The car was tight and very fast. He gutted the CATS and did not do the O2 simulator. He ran the car with and without the CATS and recorded slower times without and some minor driveability issues as well as the check light. He also was a service manager at a Pontiac dealer so he had access to the scanner, etc. and was able to verify the only glitch in the system was the post CAT O2 signal.

Anyway, long story short, I base my opinion from his experience. He eventually got the faker signal sensors and cleared it up.

It sure did sound awesome!
 
L

Ls1smlblck

Guest
What I did was run straight pipe, then cut the cats in half, gut and reinstall to over the straight pipe with U bolts when time for inspection......
 

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