Pre-cats and lambda sensors

[Briskdub]

OK be gentle, I'm more of a lurker than a poster but I do have a question. The lambda sensors come after the pre-cats but before the main cat and there are no sensors after the main cat. The lambda sensors set the emissions (don't they?) so how come we can remove the pre-cats without affecting the mot but not the main cat? I'm curious because I've just had the manifolds removed and I'm wondering about removing the pre-cats.

[haircutmike]

The pre cats as I understand are not necessary for the MOT but were for different markets.

Removing the main cat will not enable you to pass the cat emmision test on an MOT, hence a lot of main cat removers keep a catted Ypiece for the MOT.

[Briskdub]

Thanks for the reply especially as it's been covered so often before. I guess I'm just surprised that the lambda sensors are not after the main cat.

[haircutmike]

Lambdas adjust fueling but the main cat takes out the nasties so that the bunnies can breath .

[Goaty Bill]

haircutmike said:

Lambdas adjust fueling but the main cat takes out the nasties so that the bunnies can breath .

Needless to say; all the bunnies near Peter's house are either dead or gasping out their last...

[ChimpanLucky]

Goaty Bill said:

haircutmike said:

Lambdas adjust fueling but the main cat takes out the nasties so that the bunnies can breath .

Needless to say; all the bunnies near Peter's house are either dead or gasping out their last...

[haircutmike]

Some are making a comeback since I stopped No 2 son and his mate patrolling the adjacent woodland at night dressed like SAS and armed with high powered air rifles.

They loved roast rabbit!