Cleaning out Cat

[4G4D Store]

Guys - is there a way to clean out a catalytic converter? I've got one from a 3g4d that I'm working on that is blowing smoke - I swapped the cat with the other one I had and it's not doing it any more. So is there a way to clean out the bad one, or is it just pretty much shot?

[g-ride-si]

ya u can beat it until its hollow or just get another one

[jestersrain]

or do like me and cut the sum bitch out and weld in a piece of 2 1/2in piping

[91CRXTC]

i gonna be gutting out my cat by ramming a crowbar in there acouple times then rev the shit outta my engine and repete till empty.

[turtlecrxsi]

Originally Posted by 91CRXTC

i gonna be gutting out my cat by ramming a crowbar in there acouple times then rev the shit outta my engine and repete till empty.

Why don't you just unbolt it and bench gut it then bolt it back up?

[91civicDXdude]

a gutted cat is worse for exhaust flow than a stock cat. the reason being that it promotes flow stagnation. the chamber gets bigger, letting exhaust slow down & cool down, then it gets smaller.... trying to push cooler air into a more confined space means it will actually move slower than warmer air, so you basically just created a nice restriction for your exhaust.

either leave it stock or replace it with a test pipe.

[turtlecrxsi]

Originally Posted by 91civicDXdude

a gutted cat is worse for exhaust flow than a stock cat. the reason being that it promotes flow stagnation. the chamber gets bigger, letting exhaust slow down & cool down, then it gets smaller.... trying to push cooler air into a more confined space means it will actually move slower than warmer air, so you basically just created a nice restriction for your exhaust.

either leave it stock or replace it with a test pipe.

Does a high flow cat have more baffles to streamline the flow?

[91CRXTC]

ok then ill get an over sized cat and gut that, then run a 2.5" pipe through that making a cat looking test pipe or a test piped cat so cops cant bust my balls.

[turtlecrxsi]

Originally Posted by 91CRXTC

ok then ill get an over sized cat and gut that, then run a 2.5" pipe through that making a cat looking test pipe or a test piped cat so cops cant bust my balls.

Why don't you just get a high flow cat? it'll weigh less and be legal...

[91civicDXdude]

Originally Posted by 91CRXTC

ok then ill get an over sized cat and gut that, then run a 2.5" pipe through that making a cat looking test pipe or a test piped cat so cops cant bust my balls.

thats a great idea and one that i have used a couple of times. those "high flow cats" you see on ebay are definately not legal in a way, but sometimes you can fool motor vehicle inspection people. they are nothing but a glasspack.

i have seen actual "high flow cats", but they will still have the honey comb inside of the smaller shape... unless its very high dollar, it will more than likely be 'not-so-high-flow' as a smaller size denotes less area for the exhaust to pass through.

bottom line, if it has the honeycomb, its a real cat, if not, its a glass pack.

[turtlecrxsi]

Originally Posted by 91civicDXdude

i have seen actual "high flow cats", but they will still have the honey comb inside of the smaller shape... unless its very high dollar, it will more than likely be 'not-so-high-flow' as a smaller size denotes less area for the exhaust to pass through.

bottom line, if it has the honeycomb, its a real cat, if not, its a glass pack.

I haven't looked inside mine, but I paid $200 for the high flow cat from a reputable local muffler shop... we don't have inspection here anyway...

[Twyztidmind]

I dont have inspection here so i just used a test pipe off ebay. But for one of my friends that didnt live here and he had inspections, I took his old cat gutted it out, then found a pipe that would fit in there and shoved it all the way threw, cut off the exces pipe on both sides, then welded all the way around. Turned out great and fooled the inspection guys. But this was on a Nissan and they have diffrent cats then honda.