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Post #1
 18th January 2008 - 08:56 PM
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Hey. Just wondering what the use of breathers on oil catch cans and rocker covers is? Is it just for looks or does it have a purpose -------------------- I live my Life quarter mile at a time, for those 23 seconds nothing else matters
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Rancher
Post #2
Oil splashes around under the tapet cover. There is a breather that usually goes to the intake pipe, the oil will splash into the intake pipe, thus, the motor will burn it when it sucks it in. |
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STR8E180
Post #5
if ur catch can is connected to the intake system it will have vaccum so u will be sucking air out of ur crank case |
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razor-
Post #9
Ok i still dont understand.. |
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STR8E180
Post #10
QUOTE(razor- @ Jan 20 2008, 01:57 PM) [snapback]1281832231[/snapback] Ok i still dont understand.. Could somebody lease draw up a diogram of where the lines to a catch can goes because i understand what it does (Catch oil thats to close to the intake or sum poo) But dont understand how it works. If brathers are so important why arnt they on rocker covrs standard? the reason why breathers dont come standard on rocker covers is because it will be venting str8 out which means its a defect ive been defected for my breather on my catch can once already which is why im chaning my catch can setup to a twin catch can setup 
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razor-
Post #11
QUOTE the reason why breathers dont come standard on rocker covers is because it will be venting str8 out which means its a defect ive been defected for my breather on my catch can once already which is why im chaning my catch can setup to a twin catch can setup Ok thanks i kinda get it. But isnt yours in the picture breathing straight out aswell because of the 2 open holes?? When you say intake you mean air intake yer? If so why woud oil be going into there? |
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razor-
Post #12
Ok so i just seen this picture and it kinda explained it to me.. |
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STR8E180
Post #13
QUOTE(razor- @ Jan 20 2008, 05:27 PM) [snapback]1281833069[/snapback] Ok thanks i kinda get it. But isnt yours in the picture breathing straight out aswell because of the 2 open holes?? When you say intake you mean air intake yer? If so why woud oil be going into there? my 1st catch can had a filter which got me defected thats why i changed to a twin catch can setup the 2 holes ur looking at arnt my breathers remember how i said "it isnt finished yet?" when im finished with it every thing will be connected the only reason it isnt finished yet is because ive got so many other cars i need to finished i cant just drop everything and work on my car |
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bop001
Post #14
i know its on a skyline man. but its a turbo car and it gives a basic idea. |
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blacky83
Post #15
Losing "efficiency" is probably related to emissions. The idea behind the ventilation system is to stop the engine spewing out crappy gases to the atmosphere. Catch cans were to collect the oil in the vapours. |
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STR8E180
Post #17
QUOTE(razor- @ Jan 21 2008, 10:07 PM) [snapback]1281838657[/snapback] ok thanks. 1 Last Thing. If you dont have a catch can how does the gasses get to your intake? Or is that a way that some people set it up that makes it go to the intake? some catch cans will be hooked up to ur intake pipe |
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STR8E180
Post #19
QUOTE(razor- @ Jan 22 2008, 12:55 PM) [snapback]1281840489[/snapback] Ok thanks.. If you dont have a cath can just a standard rocker cver without breather what would happen to the gasses/oil? Also if you wanna fit a catch can do you have to cut a hole it it for the brather/ hoses for the catch can? u have 2 options option 1. have a filter on the catch can so it can breath <----- this is a defect option 2. have it connected to the intake pipe so it breaths back into the intake system <---- not a defect u cant not have a filter or not have it connected to the intake system because if it wont be able to breath at all ur going to build up to much pressure in the crank case and u will pop out ur dip stick and u might even pop out some seal's and cause a oil leak |
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razor-
Post #25
QUOTE(STR8E180 @ Jan 22 2008, 09:41 PM) [snapback]1281842905[/snapback] yes it would u see the 2 outlets i havnt hooked up im gonna put a little baby filter on them so its gonna look pretty nice (just need to buy the filters) But wouldnt having a filter on it be breathing to the tmosphere therefore making it unroadworthy? Would putting the hose between them be dangerous for the motor ie. Becuase there would be so much pressure in the can it could "pop the dip stick and seals" like you said earlier Or would tht take a fair amunt of driving? More driving than just to get it registered |
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STR8E180
Post #26
QUOTE(razor- @ Jan 23 2008, 02:59 PM) [snapback]1281845281[/snapback] But wouldnt having a filter on it be breathing to the tmosphere therefore making it unroadworthy? Would putting the hose between them be dangerous for the motor ie. Becuase there would be so much pressure in the can it could "pop the dip stick and seals" like you said earlier Or would tht take a fair amunt of driving? More driving than just to get it registered i dont realli give a shit about being unroadworthy any more the car isnt my daily any more yes if u put the hose between them it could be dangerous because ur catch can doesnt have any form of breathing/venting |
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MR2Mark
Post #27
QUOTE(blacky83 @ Jan 21 2008, 12:51 PM) [snapback]1281836355[/snapback] Losing "efficiency" is probably related to emissions. The idea behind the ventilation system is to stop the engine spewing out crappy gases to the atmosphere. Catch cans were to collect the oil in the vapours. Breathers will increase your power efficiency, but increase the amount of emissions you'll make. A properly set up catch can will increase power slightly by reducing the amount of positive crank case pressure contaminants taken up into the intake as per stock hose-directly-to-intake type setup. The contaminants are a mix of mostly oil vapour and combustion gases that slipped past your piston rings as blow-by. All cars have some blow-by as explained below. It also stops the crank case rubbish droplets hitting the turbo compressor blades at high speed (some believe possibly damaging the turbo or shortening its life) and prevents your intercooler and pipes filling up with oily residue. Provided the catch can is recirculated back into the intake it will not increase emissions (apart from when you empty the catch can maybe) and it will be prefectly legal. QUOTE(bop001 @ Jan 23 2008, 10:57 AM) [snapback]1281844329[/snapback] SO in a 'perfect' world, without the EPA and legal issues. what would be the BEST performance and efficiency wise in regards to either the VTA or RECIRC cans? A properly baffled catch can will remove almost all of the oil vapours from positive crank case pressure. Whether VTA or plumbed back into intake should make no noticable difference. Finally an excellent quote from tristan on mr2oc QUOTE(tristan @ January 24th, 2005, 14:41) [snapback]1281836355[/snapback] Ebay catch cans - a warning Im noticing a lot of people going out and buying ebay catch cans recently without realising how dangerous this can be for your motor so I thought I'd start this 'awareness' thread. The oil breather on the cam cover is primarily there to vent crank case pressure which is caused by blow-by during combustion. Some people associate blow-by with tired engines but all engines have an element of blow-by, even brand new motors using gapless rings.. and especially turbo motors due to higher cylinder pressures. The idea is to keep blow-by to a minimum. And the breather vents these gasses and prevents pressure buildup in the crank case. Why is pressure build up bad? Well especially as far as turbo cars are concerned, crank case pressure if not vented will travel up the turbo's oil dump and eventually blow oil out of the turbo's oil seals.. this is one of the biggest causes of turbo oil seal failure. So, why are the majority of ebay catch cans so bad? The internal diameter of the stock breather line is 14mm or more all the way through. I am seeing more and more cans pop up that have fittings that are around 4mm in diameter. Do the maths.. thats 154mm sq of flow area compared to 12.5mm sq. Only 8% of the flow capacity of the stock line! Last night a customer brought his car to me. The motor had recently been rebuilt but after fitting a catch can, he complained of his dipstick popping out and oil spraying everywhere... I identified the catch can as the problem but did some other tests on the motor to make sure. 175psi compression across all four cylinders and very low blow-by.. it was a perfectly healthy, low km motor. And yes, the catch can was an infamous ebay style job .. it had massive 20mm hoses but the fittings that screwed into the can only had an internal diameter of 4mm. No surprise the pressure was building up enough to pop the dipstick out. Thankfully in many cases the dipstick is like a fuse for the turbo.. but in many other cases the dipstick doesn't budge and the turbo is the next thing to let go. Other dangers include oil onto the exhaust or heat wrapping ... heating up and igniting... causing engine fires. It happens far too often. So - you have been warned! Use decent gear and if you're already using one of these cans, look into having the holes drilled out for larger fittings. I would personally not in any situation run less than 10mm ID fittings and lines... with 14mm being recommended. -Tristan |
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blacky83
Post #28
A breather by definition will be venting directly to the atmosphere, so whatever way you have the catch can set up if it's got a breather it will technically be illegal. |
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STR8E180
Post #34
QUOTE(Laterz. @ Jan 31 2008, 03:18 PM) [snapback]1281878111[/snapback] So many lines it would confuse a police officer/dot officer yeah i know LOL ive been defected for my breathers on the catch can once already which is why i went with this design the breathers vent into the air box  so all should be good now
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Laterz.
Post #35
If I was a police officer or DOT officer, I would deem that LEGAL. |
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