Outer Limits 4x4 Board

Does anyone know how you can tell if your cat converter is stuffed?
I remember hearing that when they are stuffed they make your car slow and sluggish!
Anyone had one go?

Chop

i belive the bang it agains the hard surface and listen for loose rattle or stuff coming out... even if it's not completely stuff it prob is a good idea to swap it anyway... get a bigger one to increase flow ( and i guess life... i mean if it is meant to filter for 5yrs on a 2.5l it's got to last like 7-8 on a 1.3 )

yeah, just bang it, see if it sounds loose inside, you could always take it off, empty the loose bits out (if they dont come out, take to it with a long screwdriver or stick) this also helps to increase the flow

yeah thats the way to go .... when did cats come in for zooks any way

i took mine out and threw it in the back of the garage.

Cats on a carbi vehicle!!! How long will that last??

General info:

If they are chemically stuffed (from leaded fuel over a period of time), the tend to make a rotten egg smell (sulphur dioxide).

Mechanically broken internals will lead to a reduction in top end power as all the bits progressivly get blown to the point of exit, thereby clogging the honeycomb at the exit even further. They only rattle if there are seriously large lumps broken off.

Heat shields generally can come loose due to being tack welded on and thermally cycled with the cat heating/cooling. The welds can break and rattle.

Ca 1975 when unleaded was first introduced, there were very few fuel injected cars. Anyone old enough to remember the Holden Torana 1900cc "Starfire Four" otherwise and better known as the "Backfire Four"??? Most US cars until recently ran carbies with cats.

DAZZ wrote:Cats on a carbi vehicle!!! How long will that last??

According to the User Manual, they last for the life of the engine providing you don't push start the car and some other things that I can't remember now.

Will

Running rich is meant to also kill them.

Just get a long screwdriver or object and punch the guts out, that way it will look like it is there but flows ok.

cheers

Polar_Bear wrote:yeah, just bang it, see if it sounds loose inside, you could always take it off, empty the loose bits out (if they dont come out, take to it with a long screwdriver or stick) this also helps to increase the flow

Long screwdriver you say simon! Well it would have to be a bloody long one coz mine is welded either side of the cat to the 2".

chop

Oh do go on haters of the world, and while your at it, club a baby seal to death. Do you put stuff in your recycle bin? Why not tip your sump oil down the drain.

Your catalytic converters are there for a reason. They can be replaced for around $150. they are a part of your emissions control system, but of course all emissions control stuff justs costs power, which is why a 7.5litre ig block on leaded in 1970 made 400 hp with "special racing equipment" and on unleaded in 2005 you can make 400hp from 6.0 litres in a HSV, through cats.

Do the right thing and repalce you cat converter when they are stuffed. you might just be able to sleep at night.

sorry about that everyone, but I can't see what everyone has against cats.

I have nothing against them mate, i just wanted to know how you can tell when there stuffed.
if mine was stuffed i'd put one back on, probably a high flow though

Chop

I wasn't having a go at you Chops, just the whole its "emissions gear - it must hurt performance" regardless of the environmental effect thing really gets up my nose.

I don't think there is an obvious way of knowing, but if it rattles, has heavy impact damage, or the rest of the exhaust is stuffed I reckon it should be changed.

I am suspiscous that if the car has been really burning oil or way off tune, this might plug them up a fair bit too- the matrix inside them is pretty fine.

I would have to say that over about 10 years old, it might be time for a new cat anyway.

steve.

from my understanding of cats ( which could quite possibly be wrong ) is they take a while to heat up hot enough to burn the exhaust gasses, so just going for a 10 minute drive down the road they arent really going to do jack besides, its illegal to run without one

Polar_Bear wrote:from my understanding of cats ( which could quite possibly be wrong ) is they take a while to heat up hot enough to burn the exhaust gasses, so just going for a 10 minute drive down the road they arent really going to do jack besides, its illegal to run without one

Not illegal if it did not come with one.

cheers