Modifying CAT convertors

[Zoro]

Hi all,
has anyone removed the original cat convertors and drilled out the "guts" to improve performance. Obviously its illegal (if you get caught) but is this an option rather than buying the high flow ones?

 

[sand_man]

yeah my boss did it on his 5L (he's an idiot).
It made no difference.

 

[GOTMYN]

Mmm...

Yeh I did it and I lasted a week before I went and had 2 new ones fitted along with a complete new system.
Removing the contents of the cat made no change to the performance, maybe worse, and gave it a tinny sound!! One of the few things I will that I wasted my time with!

Hope this helps.....

 

[V85000i]

depends though, if you don't have the cash just yet to get a new one, bashing the old one out will improve performance on a 100,000km+ car, because they get worn out and block up, it happend to me, on my old car, it couldn't rev over 3000rpm, discovered it was the CAT, bashed it out and went better than it ever did, but on your car being new, it might not do much.

 

[GOTMYN]

....

If your going to do it, don't just empty the cat and bolt it back on... doing this will create a lot of turbulence in the system and you will loose high rpm power!! At least fit a piece of pipe through the guts of the cat, to stop the air entering the cat and spiraling inside it before it exits to the rest of your system..

 

[Cobez]

Or just buy a high flow one.

They aren't expensive and it saves trouble from the law if you get busted.

 

[Not_An_Abba_Fan]

Not to mention all the crap you are spewing into the environment without a cat.

 

[sand_man]

dumb idea full stop

 

[vr_owner]

a highflow one fitted cost my brother $350. for a 3inch... not sure what brand.

 

[AttaBoy]

Don't do it. Do it the right way - buy a high flow unit.

If you can't afford it then save up.