Modifying PCV system

[A80Avant]

After my recent problem with the MAF and oil residue due to oil fumes being sucked into the MAF/compressor side of the turbo i am beggining to think about the idea of some kind of modification in that area to get rid of that part.

Im not keen on replacing the whole system with a catch tank at the moment.So without understanding much of how the whole system works,would it be possible to block the maf hose from the PCV and instead run a tube from the top to the bottom of the engine and let all the oil fumes out? Or put a filter there to filter them to atmosphere?

Will that effect the PCV system as it is,or does that area that goes to the maf always needs to be under vaccum to suck the oil fumes?

In other words,what is the easiest thing to do to get rid of the hose that goes to the MAF from the pcv system?

thanks
vasilis

[newsh]

Disconnect the pipe to the MAF hose, block the hole and run the pipe to a catch tank with the output to a filter or a long tube downwards. You will still get vacuum to the sump on idle but the fumes will go straight to the IM. Leave everything else stock. On boost the fumes will go to the catch tank. The carbon can will still work.

[Billman]

Where should the catch tank be placed i i want to ditch the PCV system completely? What are the benefits to the suggestion above?

[S2central.net]

@Billman - search function is your friend... there are lots of threads on catch/cyclone tanks.

[Jamo]

See Andy Casey's catch tank thread

[terrybullwon]

Or some where i have documented AN fittings for the sump, the darlics head on the block and back of the cylinder head cover.

[Jamo]

Or some where i have documented AN fittings for the sump, the darlics head on the block and back of the cylinder head cover.

We aren't all on Speedflow's xmas list

[newsh]

Basically there are 2 vents from the engine, at the sump and the rocker cover, take these to a catch tank and take the output to atmosphere.
There are 2 inlets to the intake, "A"at the MAF hose and "B" under the IM near the throttle body, blank both of these off. Throw everything you've removed away (or save it to put back on later). Variations on this get more complicated with no real world advantages. If you want to keep the carbon can you can connect the little electrical valve direct to point "B" the valve clicks open when the throttle is closes and applies a little vacuum to the Can.

[terrybullwon]

We aren't all on Speedflow's xmas list

Remeber what that rep for aero quip said... it had to be taken with a pinch of sodium but i think i will adhere to it

[A80Avant]

This got a bit sidetracked

Newsh, for me that i just want to keep most of it but eliminate the MAF hose, what is the difference if i just put a hose from the head to a filter,rather than have a catch tank?
Is the catch tank attached to any vaccum to gather the fumes?

[Jamo]

You need a catch tank, a filter can't cope with the amount of vapour thrown out.

Even with a filter on a catch tank it spews out a load of vapour.

[A80Avant]

oh i see,so i could only connect the catch tank to that hose that was going to the MAF then?

[Jamo]

oh i see,so i could only connect the catch tank to that hose that was going to the MAF then?

You could have a catch tank then filter that's located under the car or take the catch tank output into a bottle and collect the fumes in that.

A filter on top of a catch tank would block quickly, Doug_RS2 had this setup originally and had to change it.

Pixsaudisex2 has a setup from catch tank to a bottle I think he has pictures on here.

Mark Halligan has the ultimate setup though.

I'm not going for a straight catch tank, I bought a cyclone oil separator from a group buy on the forum and will redirect it back to the MAF hose and drain to sump.

It keeps the system enclosed but with more fumes taken out.

[S2central.net]

You could do it that way... Meaning that the catch tank prevents all the vapour spew that was headed for your MAF hose... This is arguably less work than removing all the PCV plumbing and connecting a catch/cyclone onto that directly.

You need to consider on the catch tank whether you wish to collect the oil in there - with a drain plug - or have it drain back to the sump automatically... For the sump connection - the drain plug MUST connect below the oil level in the sump... Otherwise you will just present crankcase pressure to the drain on the catch tank.

I say catch tank... you really want a cyclone tank that helps separate the oil from the vapour... Cyclone tanks have lots of internal plates to increase the surface area inside the tank - helping promote oil to drop out of the vapour, collect on the plates and drip down to the tank area - where it can stored or drained back to sump. The other upside of a cyclone is that the vent filter on the cyclone doesn't clag up with untreated vapour - this can really stink depending on location with an ordinary catch tank and how much blowby you have.

[S2central.net]

ps - my post 14 was to A80Avant... Not Jamos near simultaneous post... seems like we are aligned in thoughts though !