what sort of gains are to be had from removing the cat?
I know about the implications but it is just curiosity.

 

You'll gain a CEL in the dash when the 2nd O2 sensor detects it is not working. Modern cats are pretty low-restriction; about like a resonator. Certainly better than those abominable 200cfm pellet-type GM catalysts in the 70s that made the Corvette go 0-60 in 9 seconds.

 

You will get a raspier and bit louder sound in the exhaust.
Depending on your mods your Mini will be a bit livelier, a bit quicker and a bit stronger in the higher rpm.
And yes, you will get the dash light.

 

If you live in the "Peoples Republic of California" they will take your car:impatient

 

I try to remove the cat everytime i drive.

 

In the EVO, a high flow cat is worth about 7-10, and a test pipe (open pipe) is worth 20hp

 

Ask kaeleria, he's been trying to remove a cat from his car forever.

Oh, you're not talking about that kind of cat. My bad.

 

Hmmm sounds interesting 20 ponies.
does anybody have a little more accurate info regarding the cat restrictions,
I know some of the twincharge kits do away with the cat altogether e.g. SPI
so there is a way of fooling the second o2 sensor into thinking the cat is still there maybe place a resistance across the sensor.
anyway the numbers im more interested in.
just want to know if the cat was bypassed would the gains be noticeable,
I mean going from stock to 15% noticable?????

 

I gained about ten WHP (dyno jet WHP) but that also needed to be tuned to see it...

the thing with an EVO or any turbo car...less restriction ...better spool...more power...and sooner to boot.

 

...unplug the wires on the second O2 sensor. That has been done without throwing the light.