Thread: High Flow Cats,

not even an opinion?

I totally agree................
















you do rabbit on hahahahaheheheheh

Rabbits? Cats? This place is going to the dogs, I tell ya.....

Originally Posted by Pedro_The_Swift

not even an opinion?

Oh alright, I'm not doing anything at the moment...

All and anything you do to improve and smoooth the exhaust flow is a Good Thing, even if you add (or keep) a cat. in the system.

Interesting observation from LR trained mechanic, that taking a cat OUT, such as when one fits a 'DeCat' pipe... can work against you by means of upsetting the O2 sensors. Result is less power or more fuel used.
These need to be hot to work properly/accurately, and whilst the Rover ones are self-heated, they will reach operating temp quicker if there is still some exhaust restriction. (Cat in place) Also, this keeps sensor temp more stable.

It makes sense that the whole feedback loop is engineered around 'restriction', exhaust gas mixture/temperature and an operating window. Alter one and the rest may be affected.

My tuppence worth on a slow Sunday arvo...

FWIW, I've been informed (from here as well as elsewhere) that the 3.5/3.9 exhaust manifold is not as poorly designed as the head and inlet plumbing...

you are the second person to tell me the increased airflow speed without the cats upsets the O2 sensor,,

So "back pressure" is a good thing.