Catalytic Converter

[Pixel]

Catalytic Converter

Ive been told that removing the Cat is a fairly easy to do job, required welding and it increases the cars bhp and torque.

[HDi fun]

You can replace a cat with a straight pipe. Contrary to popular belief, the cat is not a legal requirement and if the car passes the MOT emissions test without it the you can drive without it.

You will get a bit more power as the back-pressure in the system will be lower

[aswearing]

but to be fair not many do or can.

[pgarner]

no some cars will evenn fail with sports cats fitted what i used to do with ma civic was leave the pipe on duing day to day running and refit the cat for mot's

but the cat was seperate and only had 5 bolts holding it in place wot you might be beter doing if getting alower part of the mainifold and cat ppe custon made then swaping it after the mot

might not be worth the touble tho you might only see 3-5 bhp increae

[HDi fun]

I'm thinking about diesel here. I think it's mandatory for the cat to remain in place on a petrol car.

[pgarner]

yeah the diesel exuast has to have a cat due to the smoke particals more than the emmissions

[HDi fun]

The cat does nothing for smoke, sadly. Smoke particles are removed by the DPF, FAP, call it what you want. The DPF is mounted adjactent to the cat on the engine facing side.

It's purpose is to collect smoke causing particles and then burn them off periodically with the help of a fuel catalyst (Eolys, a product of Rhodia, formerly Rhone-Poulenc) and with additional fuel injection cycles during the expansion phase. It's the equivalent of a horizontal chimney fire in my opinion and is a step too far too soon.

It works, and keeps the cat soot free but adds massively to the complexity of the car.

I presume it's possible to split the particle filter and cat, replacing the DPF with a straight pipe and then re-map the ECU so that it no longer looks for excessive back pressure and does not try to fire off a regeneration cycle.

So bloody much for diesel engines being simple!!