GolfGTIforum.co.uk
General => The garage => Topic started by: dilbert on 25 September 2011, 23:34
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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
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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.
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why wont it pass mot ? emissions ?
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I believe your not allowed to vent the crank case into the air. I may be wrong.
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>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.
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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
(http://i540.photobucket.com/albums/gg335/dazvdubba/005-9.jpg)
(http://i540.photobucket.com/albums/gg335/dazvdubba/003-15.jpg)
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thanks for the pics. :wink:
still not sure why your not allowed one on a mot. dont think the tester would pick that up tbh :S
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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.
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>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
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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
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Are catch cans really worth fitting :undecided:
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Just an additional filtration system stopping heavy oils recirculating back into the intake, no one has noticed an improvement with the engine life span, but supposedly they help in the power department due to the heavy oil fumes not recirculating. How true this is I'm unsure, need the myth busters!
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catch cans help inprove power on f**ked engines as they blowby loads of crap that contaminates the intake charge, heathy engine dosent breath that much so no significant change.
TFSI /FSI engines really need a catch can but for other reasons, as they don't inject fuel into the ports by directly into the cyl there is no fuel been sprayed over the inlet valve to kmeep it clean, hence the oil mist that settels out on the valve and port walls builds up and bakes evenetualy forming a rock hard layer that keeps building up and causes problems. and it's an absolute twit to clean off ( strip head and shot blast the ports type twit )
hopefully vag have sorted this now by now anyway
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Interesting stuff, I knew about the whole charge air being kept clean but never knew the TSI/TFSI engines had that issue with valves.
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its not just the TFSI and TSI. its a problem thats related to pritty much any direct injection engine.
diesels choke themselves as well, but it's less noticable on them but take the manifolds off onne thats done high miles and its amazing how much the intake will have furred up, why egr pisses me off, soot + oil vappor = gunk