Technical Single High flow catch can system for n54

[martymil]

So I've been trying to work out how to clean up my engine bay and came up with a single catch can system that can handle recycling the blow by whilst on boost
and draw out positive crank pressure whilst off boost.

I think this will work and simplify the whole system quite nicely.

It will also work out a lot cheaper than the current systems, have twice the flow of anything currently available and far less maintenance.

You will need an aftermarket rocker cover and head ports plugged to make it simple and effective.

Please only constructive criticism and ideas.

Lets keep it clean.

 

[V8bait]

@Aaron

 

[martymil]

Just a simple 4 port catch can design that can be customised to someones needs/wants.

 

[Torgus]

What is the vac source?

 

[martymil]

Manifold or throttle body

 

[Torgus]

But what do you do under load? Those are no longer under vac. Twins use the rear turbo inlet for vac under load right?

 

[martymil]

the rear inlet will do the scavenging under load or you can vent it to atmosphere.

 

[Torgus]

the rear inlet will do the scavenging under load or you can vent it to atmosphere.

If it is VTA than there is not vac source so under load and it will not pull/scavenge anything from the vc right?

I was under the impression if you externalize both the low and high side of the PCV system it does not work correctly if there is no vac source under load?

 

[martymil]

As long as it breathes so there is no positive crankcase pressure, I'll plumb mine back into either front or rear turbo inlet as I like to have it recirculate.

 

[Torgus]

As long as it breathes so there is no positive crankcase pressure, I'll plumb mine back into either front or rear turbo inlet as I like to have it recirculate.

Gotcha I was under the understanding it needed to be under vac to work correctly. Not just that it just needed to be able to breath easily. I went as far as to use my single turbo filter as the vac source for under load.

Sounds like overboard you think?

 

[martymil]

Not overboard at all dude, keep things green and environmentally responsible for our kids.

Forgot to mention you will need an aftermarket rocker cover and plugged head ports for this to work properly or take steps to modify your stock rocker cover but not worth the hassle
as we change it to make the car more reliable in the first place.

 

[Cruizinmax]

One observation that I have not seen addressed here or by VTT is the "metered vacuum leak." If that is not filtered, you are sucking unfiltered air in to your crankcase along with all the contaminates and dust it contains. I would recommend filtering that somehow.

 

[martymil]

You could easily put a oiled foam filter on it I guess, not a bad observation.

 

[The Convert]

The domestic guys here in the US, not sure what you aussies would call them, have been using vacuum breaks for years and years. No clue what they’re doing or what the ones they’ve been using do about filtering the air, but might be a decent place to look for ideas.

 

[martymil]

I'll be using the VTT vacuum relief valve to meter the crankcase, its cheap, reliable, billet and you can easily fit
a 1" crank case breather over the top of the valve to filter the air quite easily.

Take a pick of filters from any catalogue of different brands, heaps to choose from and it wont restrict flow.

You could even simplify the system even more and run the oem flapper valve from the catch can and not run the metered relief valve at all.

 

[SD Garage]

Nice, can't wait to see your completed setup.

Always wanted to setup a single catch can setup. Been debating on setting one up with the Nuke competition catch can. It's a dual inlet setup and single outlet. Was going to try both sides vta out the single outlet but not sure how well this will work.

 

[martymil]

Should be completed and ready for powder coating next Saturday just waiting for weld on fittings to arrive.

I've got a few designs in mind for ff and stock style manifolds.

 

[iminhell1]

I mean the car has a vacuum pump ...

Just have to watch the flow you allow to go to it. Line size is critical.

 

[martymil]

Actually line size would not matter as the metered vac relief valve will control the flow, it would only take a little longer initially to build up the vacuum in the system.

Using larger lines is actually better up to a point as when blow by starts to build and vacumm cant keep up, positive crank case pressure has to go somewhere this is when bigger lines and a large flapper valve is necessary as you need to evacuate large volume of gas especially at high psi boost levels.

 

[iminhell1]

Actually line size would not matter as the metered vac relief valve will control the flow, it would only take a little longer initially to build up the vacuum in the system.

Using larger lines is actually better up to a point as when blow by starts to build and vacumm cant keep up, positive crank case pressure has to go somewhere this is when bigger lines and a large flapper valve is necessary as you need to evacuate large volume of gas especially at high psi boost levels.

No I'm talking about the vac pump pushing air into the same space you're evacuating from. It would work under off boost situations assuming the catchcan volume is large enough.
On boost you're best to VTA.