Hi Alex hope you are well.
Just looking for some advice regarding catch cans, what do they do, and do you think they are necessary?
Hi there....
The problem with the TFSi is the multitude of breathers,all of which feed back into the induction system at some point.
They can be pretty innocuous,like the EVAP hose feeding into the inlet above the turbo,or a real pain,such as the crank and cam cover breathers,all of which dump oil and water vapour directly into the inlet,and then the crap ends up on the inlet valves like this....
A catch can and PCV kit will remove this to some extent,but it still won't catch gunk from one of the cam breathers,which exits directly into the turbo inlet.
That's proven by the fact that even if you have a catch can,the inlet valves still get gunked up after some time,although there's no doubt that any of the stuff you catch is a good thing.
So....cutting a long saga short,I do think a catch can/PCV revamp is worthwhile,but it will not catch all of the gunk unless ALL of the breathers are re-routed outside of the induction system.
That means doing away with the PCV system altogether,but also providing a way for the cam cover and crankcase to be scavenged adequately,and as far as I can see,the only way is to use a vent-to-atmosphere system like mine,or trailing the breathers out under the car somewhere,which is not ideal.
