Polo g40 breather system

[John-125]

Can I just run a catch tank off of my breather pipe
Coming out of the block ?

[z3i]

Thats what ive done and most peeps do

just MAKE SURE! the hose is big, the same diameter as the bit coming out of the back of the block, and the vent on the catch tank is big too otherwise you could blow a charger seal! which people have done

[scully]

I was just wondering what the real advantage is. Surely you will not get any oil vapours in your engine, but with a catch tank you have atmospheric pressure (or higher if not correct executed) in your crankcase. With the original system, your pressure beneath the cylinders is lower because the charger is pulling air, right?

[Ben.lopo]

Are you getting oil coming out the breather ? If so get a catch can if not don't worry , ;-)

[GR40]

I was just wondering what the real advantage is. Surely you will not get any oil vapours in your engine, but with a catch tank you have atmospheric pressure (or higher if not correct executed) in your crankcase. With the original system, your pressure beneath the cylinders is lower because the charger is pulling air, right?

I don't think there is ever lower than atmosphere pressure in your crank! Nor I believe there is enough pressure drop in the intake of the charger, to cause lower than atmospheric pressure in your crankcase. The reason the crank needs a ventilation is rather the cause of blow-by gasses that pressurize the crankcase. The vacuum of an intake manifold or the vacuum at the intake of a charger I believe is used mainly to recirculate the gasses back into the combustion chambers for cleaner emissions etc. The advantage of a catch tank install with an open to air ventilation is you get a bit "cleaner" mixture at the intake.

[scully]

I don't think there is ever lower than atmosphere pressure in your crank! Nor I believe there is enough pressure drop in the intake of the charger, to cause lower than atmospheric pressure in your crankcase.

I believe you are correct. When pressure at the charger intake is lower than atmospheric, you need to make sure that you have atmospheric pressure at the intake otherwise you lose power. So in that case, a catch tank is better yes, because of the cleaner air into the engine.

[John-125]

Thanks lads thats very helpfull  now to try and find a nice looking one :/