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A1 A2 German
10-04-2011, 12:25 AM
So I'm in the midst of tracking down another catch can set up and ran across some info that now has my head spinning. Now it gots me wondering if my entire existence of a modded Audi is being hammered with low (slow/hampered) boost build up. If so..I'm also kinda excited as it means I'll get more power, throttle response, etc.

I installed the 034 Motorsport block bung years ago, and ran it to a catch can which was vented (as seen below). Reading up on other forums there's a huge WTF concerning vented catch can as you've basically created a open atmosphere element. So what's the truth here?

I mean, the block HAS to be vented, however if going to a can which is non-vented it's sealed so the block can't breath.

So....vent the valve cover and run both that line and block breather line to the same catch can 100% sealed?

http://i41.photobucket.com/albums/e259/Blakelikesfood333/CatchCan.jpg

M-Hood
10-04-2011, 01:40 AM
I installed the 034 Motorsport block bung years ago, and ran it to a catch can which was vented (as seen below). Reading up on other forums there's a huge WTF concerning vented catch can as you've basically created a open atmosphere element. So what's the truth here?



What do you exactly mean by Open Atmosphere element? With a vented can your venting the pressure to the Atmosphere. A vented catch can is not meant to be setup with a vacuum source that is going to the turbo inlet hose like the OEM setup.





I mean, the block HAS to be vented, however if going to a can which is non-vented it's sealed so the block can't breath.

So....vent the valve cover and run both that line and block breather line to the same catch can 100% sealed?



It isn't like a non vented catch can has no outlet to release the pressure, it has a inlet and outlet. The outlet is then connected to a vacuum source like the OEM setup which uses the turbo.


As for your picture, I sure hope that isn't some tiny hoses your using for your block/VC breather.

A1 A2 German
10-04-2011, 02:24 AM
What I'm referring to is the OEM system reintroduces the block pressure into the system completing a circuit, now I've broken that circuit. Now my block basically breaths out into the atmosphere with a catch cane that has a cone filter.

I understand a non-vented catch can still has an outlet to release the pressure (I was saying sealed to reflect whether it had a air filter or not).
The catch can I vented with a cone filter years ago. Shall I plug the breather, have the existing line going in, and another line out to the valve cover?

I have only a single vent line going to the can, it's I.D. is bigger then an AA battery.

M-Hood
10-04-2011, 02:43 AM
A line that small is not big enough to allow all the pressure out of the crank case without a vacuum source. You should never go smaller then the stock breather size that came on the car in the first place since now all your doing is increasing a restriction of flow for all that pressure to try and get out. This is why most vented catch cans have very big inlets.


You cant just seal the catch can, then run 1 hose to the block and another hose to the VC. At that point you will just have pressure being supplied by both hoses and nowhere for all that pressure to go. To connect both the block and VC to the catch can it will have to be vented with a filter like you have it now.


To give you an idea, I run -10 lines to my catch can from my block and my VC. Aaron runs 4-5 lines from his block and VC.

Corrado_Guy
10-04-2011, 10:02 AM
You must vent the crank to allow for the movement/displacement of air/fumes when the crank is turning and the pistons are moving but you don't need vacuum for this. In the old days we didn't give a flying rats ass about the environment so we vented the crank case and the fuel tank to the atmosphere. Then one day dudes with pocket protectors found this was bad so they mandated that the crank vent must go into the intake so this was burnt and helped clean the air. This is why it was done, there was nothing about vacuum or sucking fumes out, it was all about stopping the fumes from entering the environment.

It is very important that the engine breaths properly or it adds stress to it and can blow fumes/oil past seals or whatever is weaker than your vent. There is really little need for external catch cans as you don't gain any power and it really just lets crap into the air we breath. You must have flow and if you are using small lines you can expect them to freeze in winter as the moisture in the oil/fumes freeze and cause a blockage. Most cold areas also use a small heater element in the breather tube to keep the oil liquid and stop freezing/blocking in the breather tube.

I hope that is clear, vacuum is not needed on a breather as it should be able to displace the air by itself as long as the breather tubes are the correct size.

M-Hood
10-04-2011, 10:17 AM
Just have to make sure that he catch can vents are large enough to keep the pressure in the can down, if the pressure gets too high in the can it can cause the oil in the crank case to be pushed into the catch can. The higher rev the higher the pressure becomes in the engine/vc, which means the vents need to be larger. That is why I run a battery size catch can with 3 vents that are 2" openings.

A1 A2 German
10-04-2011, 10:42 PM
This is the plan:

- Larger catch can
- 2 larger cone filters to vent the can
- 10AN line from the VC to the can
- 10AN line from the block to the can

End of story.

Thanx for the help!

spindoctor
10-05-2011, 03:41 AM
A good read.

For the AEB/AJL guys with BT setup, there's no vent for the VC, just the crankcase. Now, would that be an issue when running high boost/high RPM and must I replace/mod my VC to have a breather outlet?

EuroDriven
10-05-2011, 04:06 AM
A good read.

For the AEB/AJL guys with BT setup, there's no vent for the VC, just the crankcase. Now, would that be an issue when running high boost/high RPM and must replace/mod my VC to have a breather outlet?

Get a b6 valve cover or drill your stocker. Problem solved.

M-Hood
10-05-2011, 07:28 AM
A good read.

For the AEB/AJL guys with BT setup, there's no vent for the VC, just the crankcase. Now, would that be an issue when running high boost/high RPM and must I replace/mod my VC to have a breather outlet?

ATW only had a crank case breather too, but that is plenty if your not running the car over 8k rpm. If you want to do the VC too and are looking to run -10 SS braided lines you can always just order a new 06A VC from 034 that has the breather port threaded and it comes black wrinkle coated. That is what I have on my car. http://www.034motorsport.com/engine-components-18t-valve-cover-18t-wrinkle-coated-with-an-fitting-p-757.html


Other option is to just drill a hole in the back of your stock cover or even out the side like Doctor did on his B7 1.8t while using a older style VC.
http://i912.photobucket.com/albums/ac330/tetartoslogariasmos/e283a654.jpg
http://i912.photobucket.com/albums/ac330/tetartoslogariasmos/688f3f9e.jpg
http://i912.photobucket.com/albums/ac330/tetartoslogariasmos/93f88f85.jpg
http://i912.photobucket.com/albums/ac330/tetartoslogariasmos/f7201d82.jpg

Seerlah
10-05-2011, 08:21 AM
Here seems a good place to ask. Is it even necessary to place steel wool in the catch can if it is being vented? Would this maybe allow the filter to last longer before needing replacement/cleaning?

Corrado_Guy
10-05-2011, 08:37 AM
Here seems a good place to ask. Is it even necessary to place steel wool in the catch can if it is being vented? Would this maybe allow the permit to last longer before needing replacement/cleaning?

The steel mesh in there is a fire arrester <sp?> for when this is connected to the intake system, if you are using a catch-can then you don't have too many worries with back fires.

Seerlah
10-05-2011, 08:44 AM
I thought it was used more as a filtration peice.

M-Hood
10-05-2011, 08:52 AM
Here seems a good place to ask. Is it even necessary to place steel wool in the catch can if it is being vented? Would this maybe allow the permit to last longer before needing replacement/cleaning?

Would only need to be used if using a sealed can that is connected to the turbo inlet hose.

Corrado_Guy
10-05-2011, 09:31 AM
I thought it was used more as a filtration peice.

There is not much to filter coming out of the engine and if there is you have a lot more problems than you may think. Oil shouldn't be coming out here unless it is in the vapor form so there is no real purpose for it really. Because this line is connected to the intake system and back fires in the system can happen this is just used to stop flames from entering the motor and igniting oil fumes.

mysman
10-05-2011, 10:42 AM
So I'm in the midst of tracking down another catch can set up and ran across some info that now has my head spinning. Now it gots me wondering if my entire existence of a modded Audi is being hammered with low (slow/hampered) boost build up. If so..I'm also kinda excited as it means I'll get more power, throttle response, etc.

I'm not convinced that installing an open catch can will improve performance on a typical street setup. You realize, of course, that removing the OEM PCV system and venting to atmosphere will also accelerate carbon build-up in the head?

M-Hood
10-05-2011, 12:43 PM
I'm not convinced that installing an open catch can will improve performance on a typical street setup. You realize, of course, that removing the OEM PCV system and venting to atmosphere will also accelerate carbon build-up in the head?

It can cause more build up if the catch can can't handle the amount of pressure trying to get out of the crank/vc. This is why it is important to use the right size catch can and right size hoses/lines for how high you rev the motor.

I switched to a vented catch can back when I was running PES T28 kit which was 10 years ago, haven't had any carbon build up issues during that time.

rodhotter
03-26-2013, 05:13 PM
check out shophemi.com theres an informative article on catch cans

catbed
03-26-2013, 05:40 PM
Please check thread dates before replying lol

A1 A2 German
03-26-2013, 08:13 PM
Lol wow...yeah....got a pretty tricked out system now.

redline380
09-25-2014, 07:59 PM
Hello everyone,

As i am new to audizine I just have a few questions about the 034 catch can with metal pcv plate for b8 a4. Recently my car got a piston job done from the Audi dealer but they never replaced the the pcv with a new one and as it showed signs of failure with loss of power and car felt like shit. Then I install the forge diverter valve thinking it will help but it still would not accerelate the way it should so then I installed the 034 catch can with the metal pcv plate. Now car runs great holds boost well and car feels very good. But I have like a lot of blowby in the can every time in drain it say like 400 miles. Also I heard the metal pcv over pressurized the crankcase leading to seals leaking is this true? I will really appreciate some good info. Please if any one can help. How can I vent the pressure out?

Welcome to Audizine. Not trying to be a douche at all, but...

- Don't necrobump threads. This means searching and finding one that hasn't had a reply for a year then replying.
- Find the correct section. This is the b5 section, not b8. We have some smart guys around here, but not everyone knows about the tfsi engines.

Now, what you need to do; find the b8 a4 section, continue to search, and if you don't find a recent thread to answer your question, start a new one.

pratiksoni1
09-29-2014, 01:11 PM
thank you sir dint realise this. sorry for the mistake.