Guide - How to fit a catch can and simplify the PCV system

ReDBull said:
This is the set up I've got to fit.
772545A4-43AF-41F4-BD06-08E27E748259-110-0000002B52D23EED.jpg
I bought it second hand. Custom catch tank with two 19mm inlets, AN conections inc the INA rocker cover fitting and braided hoses. I've re painted the rocker cover and will be fitting it soon.
Click to expand...

Does anyone know where to grab the bit of metal that goes into the breather just above the oil filter, that is shown in this picture. Standard the car comes with a plastic part shown here.

BreatherSystemAUG.jpg


Also if anyone knows if you can get the rocker cover with an AN fitting built in, or do you have to weld it on yourself?

Cheers
 
IE do a metal breather to replace the plastic part number 2.
The rocker cover you can pull the metal outlet out and tap the rocker cover and then screw in an -AN fitting.
 
superkarl said:
IE do a metal breather to replace the plastic part number 2.
The rocker cover you can pull the metal outlet out and tap the rocker cover and then screw in an -AN fitting.
Click to expand...

Thanks for the reply. Didn't realise it just pulls out. That is great news, I really didn't want to go to the effort of welding it. Hope I have a tap large enough!

edit: I presume you use a -12an to closely match the 19mm size of the outlet?
 
Jenno007 said:
Thanks for the reply. Didn't realise it just pulls out. That is great news, I really didn't want to go to the effort of welding it. Hope I have a tap large enough!

edit: I presume you use a -12an to closely match the 19mm size of the outlet?
Click to expand...
Yes something like that, I've not personally done it but I plan to one day
 
Guys stupid question, will any catch can work? I cant order the saikoumichi one cause south africas post office is on strike and it will takes months to get here. The one I saw online is most likely made in china judging by the pics, will it work fine?
 
Any catch can will work, providing it seals, have the correct inlet/outlet size and simple things like that.

Are you venting back into the TIP or into the atmos.

If you are venting back into the tip, you will want a baffled catch can to catch some of the oil vapor. If you are venting to the atmos you could use a coke can if you really wanted, it doesn't really matter (I wouldn't recommend the coke can :p)
 
This is what they look like, I dont know a huge amount about mods so I was only aware about venting into the tip. Looking at the pic can you tell if its a baffled catch can?
 

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No idea looking from the outside. Try google and find out? You could just vent it to the atmos. So you block the tip with a cork or something, then just let the catch can vent to the atmosphere (you might get a slight oily smell but that's about it).
 
Do the baffled catch cans just have a different inside? I see a thread about one that looks similar and I see there are nothing inside just an empty can and no filter system
 
Nothing inside means it's not baffled. Personally I wouldn't plumb it back into the tip as it defeats half the purpose of installing one. No harm in doing it, but oil lowers the octane in fuel meaning less power. Whether you notice it is questionable though on a standard car
 
Its got a stage 1 remap but I will be going for stage 2 before the end of the year, I'm gonna go speak to one of the only places that sell forge motorsport stuff near me and see if they can get me the saikoumichi one (I wont even have to worry about it getting stolen at customs then) else I will get that one and mod to make it baffled. Thanks for the help with my stupid questions :)
 
No worries. To be honest the best bet would be to use any catch can and let it vent to atmos. Less chance of vac leaks and just better overall
 
rushton said:
Just touching on blanking the suction off on the brake booster pipe.

Found this http://www.dphsiliconehose.co.uk/index.php?route=product/product&path=63&product_id=308, which seems ideal. However the picture doesn't show any 1 way valve fitted. I have a AMK engine and would assume it still needs it?

If anyone could refer me to a suitable check valve to use with this pipe that would be great.
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Some threads I have read say there is already a 1 way valve on s3's elsewhere and you dont need to put it in there, others say it needs to be put in there. Just to be safe, I just used the one that came of the pcv and stuck it there, its the one circled in red.
 

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Hi I am planning on fitting my RSP oil catch can tomorrow, but at the first stage only replacing the
oil filter to t peice
Rocker to t price
T piece to catch can
Catch can to puck
Puck to tip

I have all the parts but I think the catch can is totally empty, also there is no way of getting into it or drain it. Is that normal or should I be trying to feed something into it and put a wire filter on outlet to puck?

Also I am a tiny bit unsure about connecting the 19mm hose to puck, as I think I need an extra bit of plastic connector like the puck to tip? As the existing hose pushes inside the puck.
 
Well I have ordered the 2 straight 19mm joiners too now, didn't notice them before on the shipping list. So I get another weekend off.
Still annoyed no way into the rsp can, it worries me if I can push something in a pipe it can come back out.
 
I am in the midst of removing the pipe work on my AMK and can anyone confirm from the picture below that I the strange 3 hose to inlet manifold connector is replaced with the brake pipe simply connecting directly to the inlet manifold?

there doesn't seem to be the extra hose to block off? as with the original arti
IMAG1735
cle?

it seems as simple as to remove
you remove from puck
you take the oil filter pipe off using the c-clip
you take and cap the hose from the middle underside of the inlet manifold
you disconnect from the intercooler side of the inlet manifold

to replace
connect brake servo pipe directly onto the inlet manifold onto intercooler side of inlet manifold?
you reconnect the oil filter pipe with the new 19mm tube t'd onto the rocker cover pipe?
 
yeah, well I sort of did it - so far no catch-can fitted but all the PCV stuff is bypassed - had a nightmare with the oil filter breather - the end snapped off, then some of the insides crumbled away. I have managed to get a silicon pipe and connector onto it and joined it all back together.
the car feels much livelier and positive maybe just in my head or also to do with changing the rear differential oil with some posh liqui-moly.

I don't understand what the purpose of re-cycling back to the tip - I don't think I will bother with it once I have the catch can I will just vent to atmosphere and cap the TIP, unless there is a good reason to push it back through.

clearly a bit paranoid now about the crumbled bits as some fell down the hole - so will keep a close eye on the oil, maybe remove the sump on the next oil change to make sure its not going to block the oil pickup.
 
you're just going to rely on the pressure building up in the crankcase so that it vents it self?
 
Hi Alex,

I don't quite understand your post - is that a question or a rhetorical question?

From reading the various posts.

1. Some people leave as standard - okay known leaks but as designed by experts and meet emission guidelines
2. Some people add a catch can and get rid of all the extra pipes and valves and still recirculate through the tip - this is the normal pcv delete
3. Some people vent the atmosphere directly with or without a catch can - I have seen this and assumed it maybe smelt a bit

4. Some people remove the extra stuff and don't add a catch can - this is me currently as I am struggling with space and adapters to get the 1 litre catch can on the tip heat-shield.

What wont work? Does 3 have issues and really you need 2 to help suck the crankcase gases from the rocker and oil filter?

Thanks I am unsure of the best thing to do here :) I have read a couple of posts where people are talking about pressure on the oil filler cap, is that because of venting to atmosphere?

Stuart
 
actually that oil filler cap comment was me asking if everyone's filler cap bounces around at idle. With a catch can only vented to the TIP the oil cap dances about at idle if unscrewed on my car. But that question was more aimed at people still running the standard OEM set up (a good OEM setup not a leaky old one) or anyone who may have a catch can vented to both the tip and a vacuum source from the inlet manifold. The only person I know of with this sort of catch can setup is @Prawn who has only recently converted to this arrangement so that would be interesting to know...

Back to your question though I would say definitely vent to the TIP; although I know others don't and haven't seen any apparent adverse effects. Venting to the TIP leaves at least one vacuum source from the original OEM setup which had two sources. The TIP gives vacuum on boost which I would guess is the point at which blow by is at its maximum and subsequently crankcase pressure is at its peak.

Without any vacuum source the pressure in the crank has to build to a sufficient level in order to do the work to drive the gasses out the crankcase, through the pipe work to the catch can, then through the catch can (baffled or not) and then out through (I assume) a mini air filter. Assuming your catch can isn't 100% efficient then I think the air filter will become oily over time meaning the air has to be pushed harder to get through an oiled up filter.

If you've ever had a wet pollen filter and turned the fans on in the car you'll know how much extra work is required by the fans to draw in fresh air through a wet pollen filter; and 5W40 is thicker than water

I have been considering reinstating the vacuum source at the inlet manifold to my catch can setup for some months now and have a new PCV valve sitting in front of me that I bought several months ago to do the job; just never got round to it. I was thinking of doing it differently to @Prawn who has his inlet manifold vacuum take off before the catch can whilst I was thinking of introducing it post catch can so that it sucks through the catch can. I think Prawns argument was that taking a vacuum source off just after the crankcase in the OEM position like he has means that the 'oil' is still in a hot mist form so is no big deal if sucked into the inlet manifold and ingested by the engine whereas sucking through the catch can runs the risk of sucking the coagulated liquid oil from the catch can into the inlet manifold? I guess I was hoping that it shouldn't be possible to suck out the liquid oil through a baffled catch can...
 
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I too want to do your/prawns approach. But from prawns experiences this altered the idle of the car as it had a new vaccum source. My car is mapped, so I wouldn't want it to throw anything off. Although I am me7 so maybe it can deal with it, who knows.
My reasons are for the blowby scenario you mention, and keeping crankcase pressure to a minimum, a suck and a blow is better than just a blow
 
yep; I have, in addition to the PCV valve, also bought a new jet pump thinking that its job was to magnify the inlet manifold vacuum source 'felt' by the PCV system.... was that the purpose of the jet pump in the OEM PCV system or was it to magnify the vacuum to the brake servo?
 
Hi,

Thanks for your comments, so at the moment I don't have a catch can fitted at all - simple hose from rocker and oil filter to a t-piece then the t piece to the puck which is directly in the badger 5 TIP.

The car runs well like this, it does sound slight different "air wise" not checked any logs yet eg boost - maybe tomorrow if I get a chance. the only obvious vacuum hose split was in the 3 hose connector on the drivers side of the inlet manifold on the bend from inlet u bend to pcv not the pass through to the brake servo - but that may have been caused during removal.

I will simply join tip to catch can and t piece to catch can.

I have worried too about, what if the turbo asks for loads of air and the S2000 filter cant give it, wont it suck it out the catch can? or is that the purpose of the puck?

I have done about 80 miles since the setup I have today.
 
the pressure regulating (PRV) valve or hockey puck allows air to flow from the PCV system into the TIP but limits the air that flows from the TIP into the PCV system. I think it makes sure that the PCV system isn't exposed to too strong a vacuum because that can affect oil pressure. The PRV valve is not a one way check type valve
 
So I have run to work with Android torque. The turbo PSI is still logging a peek of 30psi, I was hoping the pcv delete would drop that. The "wheel HP" 192 seems similar to the old dyno sheet I got with the car.
Screenshot 20160202 083326
i didn't really push it .The torque if you can believe the tool shows 320 lb/ft
 
Just seen the tags in this thread that I'd missed yesterday, sorry chaps.

Stuart: the 30psi you're seeing is HOPEFULLY boost + atmosph, so take away 1 bar and you're left with just over 1 bar of boost, which is closer to the truth. The MAP sensor also cannot read 30psi of boost, so it MUST be absolute pressure.

The idea of the TIP return is that the TIP is usually under a very light vacuum due to the restriction at the air filter. It's not a huge vacuum like the inlet manifold, but it is at least a negative pressure.

it's thought that this negative pressure will help to draw the crank case gasses out of the block, rather than the block simply venting itself to atmosphere.

i tried running my new catch can setup vented to atmopshere, but after around 6-- miles or so there was a heavy build up of emulsification in the crank and cam cover breather lines, and the can was collecting the nasty gunk too. You could also see the breather filter smoking when the car was run on the dyno:



This was the inlet to the can after 600 miles:



Pretty nasty.

Firstly I returned the catch can to the TIP with a 25mm line:



Then I added a T into the main crank breather near the source, to draw direct from the crank case as Alex alluded to:



Pretty hard to make out, but it's a 10mm line that runs from the OE plenum PCV take off, via a check valve, down to the main crank case breather line. This draws the crank case gasses out on over run when the throttle plate is closed, and it does a REALLY good job because there is a very strong vacuum in the plenum.

To give you an idea, the vacuum at the plenum is strong enough, that not only does it draw sufficiently from the crank case, but it also creates a vacuum at the catch can and draws any gasses out of the catch can too:



After just 50 miles with the PCV stuff, the can inlet had near on cleaned itself fully:



And now after a few hundred miles more, the can is 100% empty, and the pipes are spotless inside like brand new.

To all intents and purposes, it seems that it is now a totally self maintaining system.

I realise this goes TOTALLY against the standard ASN route of 'rip it all out it's ****'. I believe that all the stock pipework is most probably fit for the bin on any used 1.8T that's ever been sold, but when new and in good condition, it seems to be a system that works well.
 
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the PCV system has nothing to do with boost control; and I think you should log it with something more reputable than Android torque just to double check those numbers.

EDIT: ah yeah as above; if its 30psi absolute rather than 30psi gauge then that would make sense
 
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Also - Karl, my idle rose because I have no air flow meter at all, so the car wasn't to have a clue that it was now getting more air on idle.

I don't believe it'll make any difference on a car with a stock ECU, otherwise you'd see loads of posts complaining that peoples idle had dropped significantly after doing the typical PCV delete.
 
@Prawn if you unscrew the oil cap at idle does it dance around or is it sucked down onto the rocker cover?

my car does feel weak at idle and pulling away from low rpm (bit like @goodbuzzman1 issues) but my warm idle rpm is still ~900; hasn't dropped
 
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well its a little annoying after making all the effort to remove the PCV that basically it all had a purpose and now I need to introduce the centre throttle body pipe - tee'd with a valve to the catch can via the oil filter breather to control the gases and watery oil. but there was clearly a reason for it all in the AUDI labs. plus I will bin my ramair catch can air filter now too :)

I think I will get an old fashioned boost gauge, I hope the peek readings are wrong but with N75 disconnected it peaks at 11psi but struggles past 6.5psi, its difficult to watch a dial with my foot flat :)
 
I think the deletion of the PCV is causing my intermittent boost issues I have only been suffering these recently, maybe the cold weather is creating more emulsified gases and they are doing something to the turbo (as I still haven't put in the catch can), this only seems to be happening in the early mornings it's fine at lunchtime and evenings.
 
I just fitted a catch can and vented to tip. My oil cap also bounces a bit when unscrewed at idle. Is this harmful in any way?
 
IM interested in this. I have PVC delete and catch can venting to atmosphere and my oil cap bounces.
When on the dyno you could see the atmosphere breather smoking.
Ive had some random smokey idles.
Are people thinking that venting back to the tip with the hockey puck is the best way ?
 
I think the main point regarding the bouncing cap is because the PCV delete removes a non-return valve or similar, thus un-controlled suction from the tip.
 
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