oil catch can help

[dilbert]

what do they do ? stop the oil from the breathers being put back into the engine ? how are they fitted ? any pics would be great ?

thanks

[Jonny]

If the catch tanks got a filter on it will allow spent gases to escape.
Mainly it doesnt allow nasties to be put back in to the intake.

Last car used to get 2 1/2 mpg more, i put that down to not trying to burn burnt gases and such like.
These catch tanks dont need to be as big as they are, 1/4 of the volume is suffice ive even done them out of CF 1" dia, just drain once every two months.
Wont pass mot though, so remove.

[dilbert]

why wont it pass mot ? emissions ?

[molegti]

I believe your not allowed to vent the crank case into the air. I may be wrong.

[javalin]

>I believe your not allowed to vent the crank case into the air. I may be wrong.
you're not wrong!  Thats what the crank case ventilation pipes, etc, are for. :-)  Also the Evap system is used to stop venting of warm fuel vapour into the atmostphere.

[daz veedub]

what do they do ? stop the oil from the breathers being put back into the engine ? how are they fitted ? any pics would be great ?

thanks

the catch can is the 1 with the redpipes going to it

[dilbert]

thanks for the pics. 

still not sure why your not allowed one on a mot. dont think the tester would pick that up tbh :S

[golf-sib]

You're breather pipe has vapourised oil fumes coming out the engine, these are recirculated back into the intake.

These fumes are heavy, so if you flow them downwards and into a catch can the heavier molecules will stay down whilst the lighter ones will be recirculated. In it's own way a catch can is a filter. Why people do this is the recirculated oil fumes downgrade performance, which everyone into cars wants performance.

Keeping a catch can in a closed loop in the engine is fine, but if you vent gases out it's illegal, MOT failure or Mr Plod rape, plus venting fumes high up is silly, the fumes will re-enter the cabin when fans are on or windows open. if you do plan to vent to atmosphere run a nice long pipe downwards and under the chassis and out somewhere to avoid the smell and make it discreet.

[molegti]

>I believe your not allowed to vent the crank case into the air. I may be wrong.
you're not wrong!  Thats what the crank case ventilation pipes, etc, are for. :-)  Also the Evap system is used to stop venting of warm fuel vapour into the atmostphere.

Yes but they normally vent into the intake system

[danny_p]

open vents are also discoraged for track use as well,   cos when you burn a hole in piston the sump pressuries and blows all the oil out the breather at least if it goes down the intake it just makes more smoke