As the title states, anyone running a catch can? Whered you mount it, doing its job well?
Cheers.
Anyone Using a Catch Can?
Started by CRUISN, Oct 14 2008 08:31 PM
10 replies to this topic
#1
CRUISN
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Posted 14 October 2008 - 08:31 PM
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Posted 21 August 2009 - 01:00 PM
What is the purpose of a catch can? if i dont have one would oil leak on the ground when i park overnight? but why does one need a catch can (not eliminating oil leak, gotta get under and look this weekend)
#3
aekOne
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Posted 21 August 2009 - 02:18 PM
yeah Mark i've tried two different catch cans
The first one was a non breather type which was mounted on the back of the intake manifold on the passenger side:
Now i have a breather catch can which is mounted behind the right hand head light next to the radiator hose:
I haven't had either on long enough to see how effective they are but i assume it's doing it's job??
sociallydiabled - A catch can collects Blow-By from your PCV's and valve cover vent lines
More reading taken from NASIOC (author - The Deliverator)
"Catch Can FAQ
The point of a catch can is to minimize the amount of oil vapor that's fed into an engine's air intake tract.
If you've taken the intercooler off a car with even a few thousand miles on it, you'll likely have found the inside of it to be coated with a fine layer of oil. This oil coating is also typically found in the 'Y" pipe, the throttlebody, the cold side of the turbo, and the intercooler to throttlebody hose. This oil coating is very common and isn't usually indicative of a major issue.
Why would I want a catch can?
Catch cans are useful on many, many different kinds of cars- NA and Turbo Subaru's included.
There are two, maybe three specific reasons you might want a catch can:
1) You don't want to effectively lower the octane of the gas you're running- the oil vapor that doesn't condense on the walls of your intake tract ends up in the cylinder, to be burned away for emissions purposes. The effective octane of oil is significantly lower than that of gasoline; having it in the mix will effectively lower the octane of whatever gas you're running.
2) You've got an intercooler- by definition an intercooler is part of your intake tract, and It's generally agreed that an intercooler which is internally coated with oil won't be as effective as one that's clean.
3) You want something pretty under the hood.
Where does this oil come from?
On a WRX, this oil gets introduced into the intake tract via two hoses- the one coming from the PCV (Postive Crankcase Ventilation) valve and the valve cover vent lines.
Valve cover vent lines? There's more than one?
Yes, but they're T'd into that black tube which runs in front of your intercooler. The third part of the T is a hose running to your inlet pipe.
Who makes catch cans?
Everybody. Call your favorite vendor or hop over to their web site and see what they carry. Or build one yourself (see below).
Can't I just vent these lines to atmosphere?
You could indeed, but there are several reasons why you shouldn't.
1) You'll lose the benefit of having the inlet's vacuum help suck filthy air out of your crank case (thanks to Wylde Horses for this one)
2) It's bad for the environment
3) It'll make a mess of your engine compartment.
4) It'd let metered air out of the system
Which manufacturer is best?
This topic isn't really hotly debated because hardly anyone cares enough about a catch can to start a flame war over it. There are just too many factors to consider and they all do the same job. The main category breakdowns are:
a. Price
b. Looks
c. Composition
d. Features
What material is best?
Catch cans are commonly composed of aluminum, steel, and/or silicone. It's been reported that catch cans made from silicone cannot be used in certain configurations due to their occasionally collapsing when subject to vacuum.
What features might I want in a catch can?
Some catch cans include features whereby you can see how full the can is without having to remove the can from the car.
Others include little faucets so they can be emptied without having to remove them from the car.
Still others incoroprate breather filters. Essentially, these cans provide most of the downsides of venting the crank breather or PCV lines to atmosphere with the expense of having to buy extra gear to do it. If you'd like to avoid the consequences listed under "Can't I just vent these lines to atmosphere" you should probably avoid this sort of can.
Can I build a catch can myself?
You very likely can. Catch cans are relatively simple contraptions; not at all difficult to construct.
Why would I want to build my own catch cans?
Cost, mostly. Two separate cans are required for a complete installation, and using name-brand cans this can easily come to over $200. For around 1/4 of that, you can build a pair of catch cans yourself that do the job just as well.
Why would I want to buy a catch can?
Appearance and simplicity. Commercial catch cans are often very shiny and pretty. It's also rather easier to pull one out of a box and slap it in than it is to piece your own together. Vendor support might be another consideration.
What do I need to build my own catch can?
People 'roll their own' using everything from aluminum fuel bottles to sections of pvc pipe with end caps. Pretty much any sealable (airtight) container that can withstand underhood temperatures is a reasonable candidate for the body of a catch can.
You'll also need:
Various fittings -you want to end up with 3/8" male hose connectors coming out of your can(s).
3/8" ID fuel-safe hose
Some way to mount your can(s)
I want to keep oil mist out of my intake tract, but I'm too cheap to buy a catch can and too lazy to build one. Isn't there something else I can do?
Some people have had success sticking a small fuel filters between the inlet and the oil-introducing hoses. They don't hold much, though, and would likely require very frequent cleaning.
How should a catch can be installed?
There are a variety of ways to install a catch can. There's one right way, two sort-of right ways, and some would argue that at least one common installation method which is wrong.
Sort of right ways:
1) Disconnect the hose which runs between the PCV valve and the turbo inlet pipe. Run a line from the PCV to the catch can, and another line from the catch can to the turbo inlet hose.
2) Disconnect the hose running between the crank case breather lines and the turbo inlet pipe. Run new hose between the breather line and the catch can and another hose between the can and the inlet pipe.
Right way:
Use two catch cans. Configure one as discussed in option one and the other as described in option 2. For optimal effectiveness, this is the way to go.
Wrong way:
Disconnect the PCV<->Inlet line as well as the Crank Vent<->Inlet line. "T" the PCV and Crank vent lines together, and run the remaining end of the "T" to a single nipple on the inlet pipe. Cap the remaining nipple on the inlet. You'll be sending boost into places that definitely shouldn't ever see any. Bad idea.
Why isn't my catch can catching anything?
Apart from being installed incorrectly, the most common reason catch cans don't catch anything is that air flow through them is too smooth to cause the oil to condense while it passes through the can. Some sort of filtering media is often needed to help sort this out.
What should I use for filtering media?
People have used a lot of different things as filtering media. Foam lawnmower filters are a safe and popular choice.
If you decide to use media that's made of metal (steel wool, chain, etc) and have a metal catch can, be sure that they're made of the same stuff. They'll corrode if they're not, and you don't want the resulting debris being fed into your motor.
Why is my catch can full of water?
Condensation, most likely. It's almost certainly not something you need to worry about.
Blowby products (the filthy vapor in your crankcase) cool as they go through the catch can and associated tubing. As the temperature drops, water vapor condenses. This can cause a surprising amount of water to accumulate in the can. For example, I didn't check my can for about 5k miles over this last winter; poured out around half a liter of almost-entirely-water when I finally got around to it.
Where should I mount my catch can(s)?
The two most common places for mounting catch cans on a WRX are the passenger side strut tower and in front of the battery.
Are there any downsides to catch cans?
Having to remember to empty it out periodically is about the only major downside.
The only other potential downside is cost. Brand name catch cans typically cost $75 or more. Knock-offs can often be found on ebay for more reasonable prices- until you factor in their crazy shipping costs. Rolling your own (or buying used) goes a long way toward mitigating this downside.
Are there any more specific instructions out there about building a custom catch can?
Tons and tons. Search here and on Google as catch cans are a common mod on many different vehicles. Though the fitment isn't the same, the parts generally are.
Examples:
http://www.nissansil....hettocatch.htm
http://www.integra.o...net.nz/catchcan
http://www.srtforums...ead.php?t=97923
http://www.autospeed...tml?&A=1101&P=1
http://www.iwsti.com...ead.php?t=17214
Editor's Note
This post was created because questions about catch cans keep popping up. I came up with the text based on LOTS of searching, here and elsewhere, when I was building my own catch can setup. Upon reading this you should have an idea of whether or not a catch can is for you and whether you'd prefer to build one yourself or buy a commercial can.
The format of this FAQ (and much of the text in this "Editor's Note") was shamelessly stolen from the many excellent FAQ's the Unabomber's put together. If you like it, most of the credit should be his. If you hate it, it's all my fault."
The first one was a non breather type which was mounted on the back of the intake manifold on the passenger side:
Now i have a breather catch can which is mounted behind the right hand head light next to the radiator hose:
I haven't had either on long enough to see how effective they are but i assume it's doing it's job??
sociallydiabled - A catch can collects Blow-By from your PCV's and valve cover vent lines
More reading taken from NASIOC (author - The Deliverator)
"Catch Can FAQ
The point of a catch can is to minimize the amount of oil vapor that's fed into an engine's air intake tract.
If you've taken the intercooler off a car with even a few thousand miles on it, you'll likely have found the inside of it to be coated with a fine layer of oil. This oil coating is also typically found in the 'Y" pipe, the throttlebody, the cold side of the turbo, and the intercooler to throttlebody hose. This oil coating is very common and isn't usually indicative of a major issue.
Why would I want a catch can?
Catch cans are useful on many, many different kinds of cars- NA and Turbo Subaru's included.
There are two, maybe three specific reasons you might want a catch can:
1) You don't want to effectively lower the octane of the gas you're running- the oil vapor that doesn't condense on the walls of your intake tract ends up in the cylinder, to be burned away for emissions purposes. The effective octane of oil is significantly lower than that of gasoline; having it in the mix will effectively lower the octane of whatever gas you're running.
2) You've got an intercooler- by definition an intercooler is part of your intake tract, and It's generally agreed that an intercooler which is internally coated with oil won't be as effective as one that's clean.
3) You want something pretty under the hood.
Where does this oil come from?
On a WRX, this oil gets introduced into the intake tract via two hoses- the one coming from the PCV (Postive Crankcase Ventilation) valve and the valve cover vent lines.
Valve cover vent lines? There's more than one?
Yes, but they're T'd into that black tube which runs in front of your intercooler. The third part of the T is a hose running to your inlet pipe.
Who makes catch cans?
Everybody. Call your favorite vendor or hop over to their web site and see what they carry. Or build one yourself (see below).
Can't I just vent these lines to atmosphere?
You could indeed, but there are several reasons why you shouldn't.
1) You'll lose the benefit of having the inlet's vacuum help suck filthy air out of your crank case (thanks to Wylde Horses for this one)
2) It's bad for the environment
3) It'll make a mess of your engine compartment.
4) It'd let metered air out of the system
Which manufacturer is best?
This topic isn't really hotly debated because hardly anyone cares enough about a catch can to start a flame war over it. There are just too many factors to consider and they all do the same job. The main category breakdowns are:
a. Price
b. Looks
c. Composition
d. Features
What material is best?
Catch cans are commonly composed of aluminum, steel, and/or silicone. It's been reported that catch cans made from silicone cannot be used in certain configurations due to their occasionally collapsing when subject to vacuum.
What features might I want in a catch can?
Some catch cans include features whereby you can see how full the can is without having to remove the can from the car.
Others include little faucets so they can be emptied without having to remove them from the car.
Still others incoroprate breather filters. Essentially, these cans provide most of the downsides of venting the crank breather or PCV lines to atmosphere with the expense of having to buy extra gear to do it. If you'd like to avoid the consequences listed under "Can't I just vent these lines to atmosphere" you should probably avoid this sort of can.
Can I build a catch can myself?
You very likely can. Catch cans are relatively simple contraptions; not at all difficult to construct.
Why would I want to build my own catch cans?
Cost, mostly. Two separate cans are required for a complete installation, and using name-brand cans this can easily come to over $200. For around 1/4 of that, you can build a pair of catch cans yourself that do the job just as well.
Why would I want to buy a catch can?
Appearance and simplicity. Commercial catch cans are often very shiny and pretty. It's also rather easier to pull one out of a box and slap it in than it is to piece your own together. Vendor support might be another consideration.
What do I need to build my own catch can?
People 'roll their own' using everything from aluminum fuel bottles to sections of pvc pipe with end caps. Pretty much any sealable (airtight) container that can withstand underhood temperatures is a reasonable candidate for the body of a catch can.
You'll also need:
Various fittings -you want to end up with 3/8" male hose connectors coming out of your can(s).
3/8" ID fuel-safe hose
Some way to mount your can(s)
I want to keep oil mist out of my intake tract, but I'm too cheap to buy a catch can and too lazy to build one. Isn't there something else I can do?
Some people have had success sticking a small fuel filters between the inlet and the oil-introducing hoses. They don't hold much, though, and would likely require very frequent cleaning.
How should a catch can be installed?
There are a variety of ways to install a catch can. There's one right way, two sort-of right ways, and some would argue that at least one common installation method which is wrong.
Sort of right ways:
1) Disconnect the hose which runs between the PCV valve and the turbo inlet pipe. Run a line from the PCV to the catch can, and another line from the catch can to the turbo inlet hose.
2) Disconnect the hose running between the crank case breather lines and the turbo inlet pipe. Run new hose between the breather line and the catch can and another hose between the can and the inlet pipe.
Right way:
Use two catch cans. Configure one as discussed in option one and the other as described in option 2. For optimal effectiveness, this is the way to go.
Wrong way:
Disconnect the PCV<->Inlet line as well as the Crank Vent<->Inlet line. "T" the PCV and Crank vent lines together, and run the remaining end of the "T" to a single nipple on the inlet pipe. Cap the remaining nipple on the inlet. You'll be sending boost into places that definitely shouldn't ever see any. Bad idea.
Why isn't my catch can catching anything?
Apart from being installed incorrectly, the most common reason catch cans don't catch anything is that air flow through them is too smooth to cause the oil to condense while it passes through the can. Some sort of filtering media is often needed to help sort this out.
What should I use for filtering media?
People have used a lot of different things as filtering media. Foam lawnmower filters are a safe and popular choice.
If you decide to use media that's made of metal (steel wool, chain, etc) and have a metal catch can, be sure that they're made of the same stuff. They'll corrode if they're not, and you don't want the resulting debris being fed into your motor.
Why is my catch can full of water?
Condensation, most likely. It's almost certainly not something you need to worry about.
Blowby products (the filthy vapor in your crankcase) cool as they go through the catch can and associated tubing. As the temperature drops, water vapor condenses. This can cause a surprising amount of water to accumulate in the can. For example, I didn't check my can for about 5k miles over this last winter; poured out around half a liter of almost-entirely-water when I finally got around to it.
Where should I mount my catch can(s)?
The two most common places for mounting catch cans on a WRX are the passenger side strut tower and in front of the battery.
Are there any downsides to catch cans?
Having to remember to empty it out periodically is about the only major downside.
The only other potential downside is cost. Brand name catch cans typically cost $75 or more. Knock-offs can often be found on ebay for more reasonable prices- until you factor in their crazy shipping costs. Rolling your own (or buying used) goes a long way toward mitigating this downside.
Are there any more specific instructions out there about building a custom catch can?
Tons and tons. Search here and on Google as catch cans are a common mod on many different vehicles. Though the fitment isn't the same, the parts generally are.
Examples:
http://www.nissansil....hettocatch.htm
http://www.integra.o...net.nz/catchcan
http://www.srtforums...ead.php?t=97923
http://www.autospeed...tml?&A=1101&P=1
http://www.iwsti.com...ead.php?t=17214
Editor's Note
This post was created because questions about catch cans keep popping up. I came up with the text based on LOTS of searching, here and elsewhere, when I was building my own catch can setup. Upon reading this you should have an idea of whether or not a catch can is for you and whether you'd prefer to build one yourself or buy a commercial can.
The format of this FAQ (and much of the text in this "Editor's Note") was shamelessly stolen from the many excellent FAQ's the Unabomber's put together. If you like it, most of the credit should be his. If you hate it, it's all my fault."
#4
Chadza
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Posted 21 August 2009 - 05:20 PM
There was one on my B4 when I bought it, looked to be a fairly professional setup although there is no branding on the can that I can see. Its more like a rectangular box that is mounted in front of my battery. I checked it today just for shits and giggles and found it was pretty much empty!! Now unless they cleaned it out at subaru when they had my manifold off to replace my fuel regulator, Im not sure why it is so clean inside. I could see the 'filtering media' was just a metal plate with lots of little holes in it about half way up the can.
MY02 Blue Pearl B4 Manual - 185KW atw
Ecutek Stage 2, 3" DBE, Walbro FP, Hyperflow CAI
14.2 @ 158kph
Ecutek Stage 2, 3" DBE, Walbro FP, Hyperflow CAI
14.2 @ 158kph
#5
Pete S
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Posted 21 August 2009 - 05:39 PM
yeh I had a catch TMIC on the wrx, always oil in the bottom of it. Guess it was an indication the piston was going to let go which it did.
#6
Adam
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Posted 23 August 2009 - 06:42 PM
Aek, thanks heaps for ALL that info, i havent got time to read it all, but when i do im sure it will be a wealth of knowledge.
Fixed the oil leak, was a loose sump plug 
#7
XXB4XX
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Posted 23 August 2009 - 08:07 PM
Yo Pete, my cooler on the b4 was full of oil, no engine issues though, I think it's just really common on the ej engine
#8
jOhn-e
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Posted 24 August 2009 - 04:52 PM
I got a custom made one, mounted near the cruise control unit just on the right hand side of my TMIC.
Reason i got one was on a recent trip to the Snows my engine use abit more oil than it used to. Probably high gear and high boost on the freeway.
Found some of it in the TMIC and since decided to get a custom one made.
Now car breaths better and i dont lose any oil anymore.
TMIC is clean as a whistle too 
For all Your Performance Work and Needs.
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Fairfield East NSW 2161
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#9
Adam
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Posted 24 August 2009 - 06:07 PM
What should i be looking for in a catch can? and how much should i be looking at spending? the prices of ones ive looked at seem to vary between 80 and 300 dollars
#10
jOhn-e
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Posted 25 August 2009 - 08:31 PM
What should i be looking for in a catch can? and how much should i be looking at spending? the prices of ones ive looked at seem to vary between 80 and 300 dollars
Depends on your build.
Out of the box catch cans are fine but aint all that good for bigger builds. If you are planning a big build i would recommend a custom one made.
Just make sure when you buy the correct hoses for the catch can, i got mine from Pirtek and they dont kink when they are bended.
For all Your Performance Work and Needs.
Address : 8/88 Seville Street
Fairfield East NSW 2161
PH : (02) 9755 9882
#11
jOhn-e
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Posted 25 August 2009 - 08:35 PM
Depends on your build.
Out of the box catch cans are fine but aint all that good for bigger builds. If you are planning a big build i would recommend a custom one made.
Just make sure when you buy the correct hoses for the catch can, i got mine from Pirtek and they dont kink when they are bended.
Site is still in construction but you can see some custom catch cans here and the hoses you should use for them as well.
http://www.toysgarage.com.au/
For all Your Performance Work and Needs.
Address : 8/88 Seville Street
Fairfield East NSW 2161
PH : (02) 9755 9882
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