Club G40 Forum

Technical => Engine and Transmission => Topic started by: John-125 on May 27, 2014, 07:41:41 PM

Title: Polo g40 breather system
Post by: John-125 on May 27, 2014, 07:41:41 PM
Can I just run a catch tank off of my breather pipe
Coming out of the block ?
Title: Re: Polo g40 breather system
Post by: z3i on May 27, 2014, 09:43:32 PM
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

Title: Re: Polo g40 breather system
Post by: scully on May 28, 2014, 05:20:23 AM
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?
Title: Re: Polo g40 breather system
Post by: Ben.lopo on May 28, 2014, 10:37:13 AM
Are you getting oil coming out the breather ? If so get a catch can if not don't worry , ;-)
Title: Re: Polo g40 breather system
Post by: GR40 on May 28, 2014, 09:17:26 PM
Quote from: scully on May 28, 2014, 05:20:23 AM
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.
Title: Re: Polo g40 breather system
Post by: scully on May 29, 2014, 08:13:27 AM
Quote from: GR40 on May 28, 2014, 09:17:26 PM
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.
Title: Re: Polo g40 breather system
Post by: John-125 on May 30, 2014, 10:20:45 AM
Thanks lads thats very helpfull  :) now to try and find a nice looking one :/