enzo_e492901

It's hard to see in the photo but are the only pipes going to the catch can the 3 from the valve cover? Is the can sealed?

Edit: It don't look good tho. Even if the blow by made it into the can where does it go then?

Gavin

Ok, I see your point...

Hmmmm, its got me wondering how you would set it up with 1 can on a turbo system now???

I think the way I have it would still work on a turbo. Chris will tell you, I think he knows a little more about turbos than me.

i still quit lol there no reason to have a racespec rocker cover really is ther

I guess the point of a race spec cover is the bigger bore lines designed to be used with inline PCV/check valves.

Gavin

Why wouldnt that work?

It would under boost. When under vacuum it would be worse than stock because nothing is being drawn directly from the valve cover. Vacuum would draw air into the can then into the manifold, missing out the valve cover.

I give up!

Gavin

how can i stick a line before my airfilter? lol

You can insert a line in any silicone hose and some hard hoses using one of these <Click. You will however have a hard job putting anything before your air filter. lol

Gavin

If using only 1 catch can, this is the only way I see you being able to use the system to its most efficient potential...

and you really wouldnt even need the PCV on the rocker cover anymore with it that way.

In my humble opinion, that does not work.

Gavin

I really thought I had it, now it looks as though I was miles out!

What happened to PCV Breather - Catch Can - One Way Valve - Intake?

And the other breather going to the intake with a catch can in-between?

Jamie

You can do it like that but this is a way of doing it to both pipes with only one can.

Gavin

by that do you mean full throttle?

No, vacuum is stronger at idle. At full throttle vacuum is nill and on a turbo vacuum goes as soon as boost kicks in.

Gavin

Ok, but what happens when you hook this up with a turbo setup, pre-turbo?

The wheel in the turbine would create more suction...and that suction would greatly increase the more throttle you give it.

That's a good point. I'm an n/a man so i'm not sure to be honest but I guess it would. The turbo then has an added benefit that the blow by gets drawn out either way because when there is boost in the manifold there is no vacuum. I can tell you tho that anything being drawn from the valve cover would still pass though the catch can.

So untill the turbo starts spinning it would act like an n/a.

Gavin

So in essence, its working like this?

When under vacuum, yes.

Gavin

This is the portion I am confused about. Only when the system is under vacuum does this not make sense in the way I see it drawn in your diagram.

If the Intake Filter is sucking in air from an outside source, then any hole along that pipe is going to create air flow in the direction of manifold...and the crank case is pressurized, so along with that and the vacuum, how is it you would get air flow from the intake pipe to the rocker cover?

Just looking for clarification cause this makes no sense to me when looking at it from a Fluid Dynamics stand point.

Because of the pressure difference across the throttle body butterfly the vacuum in the manifold is stronger! Stronger vacuum means flow in that direction.

Gavin

But there is still vacuum in the pipe between the filter and the manifold, so that would draw air from the crank case in the first picture...but with both those 1 way check valves, in the first picture the only port doing anything for the rocker cover is the one going directly to the catch can.

There is very little or no vacuum in the intake tube because of the pressure difference across the throttle body butterfly. It's something to do with the Venturi effect so i've read.

Yeah the blow by always goes down the same pipe in this setup, you could run as many pipes directly to the catch can as you like.

Gavin

With the system below when there is manifold vacuum, that vacuum draws fresh air from the intake tube through the valve cover then through the catch can and into the manifold taking blow by with it. When there is no vacuum the pressure in the crankcase has to find it's own way out (it does not have a vacuum or fresh air to help it) through the catch can and into the intake tube. Its all to do with the check valves, some are open and some are closed.

Gavin

thats the 1 but i was not even going to try and explain this setup. i know it can be done but i had not even fronted it yet, good work gavin this is the 1 can way.

which makes the racetec look like a total bodge job.

chris

Cheers Chris. It's a little plumbing crazy but it works!

I hope I have not confused the rest of you too much.

Gavin

Now I'm lost!?! I thought the flow on both breathers was out? Not one going in?

Jamie

As said before when everything is stock fresh air is drawn in on the right (n/a) or front left (on turbo) when there is vacuum, it's to help draw the gases out! When there is not vacuum gases flow in the other direction.

See post 96 in this thread.

Gavin

In the last few days I've put some more thought into trying to use one catch can to catch the oil/blow by/water vapour from both pipes. It is possible but there is a little more plumbing and you need 3 check/non return valves. The advantage to only using one can though is you only have to empty one can and you save a little space!

Gavin

Meh, UKSC ones are better

I did not know there was one. lol Who sells them?

Gavin

Top guy! Very friendly and very good communication. He went out of his way to help me!

Everything was as described and the parcel was well packaged.

Thank you

Gavin

I can't see a way with just one can, no. If you used one can the pipes would basically be connected together and one pipes function would interfere with the others function.

Gavin

My very basic attempt at a drawing.

Just to make sure, you can't use the same can for both pipes!

Gavin

I would say it's not practical for space reasons. If you have the space then it's all good!

Gavin

Also there is nothing wrong with race spec rocker covers. Using large bore pipes can't hurt anything but people that use them need to use an in line check valve (non return valve) to act as a PCV valve.

Gavin

Sorry guys just got back from work!

Cheers Chris! <This man knows his stuff too lads!

Yeah running two catch cans/tanks would be the ideal solution, one in line with each rocker cover pipe. But that's not practical. If only using one can there is a big debate as to which pipe to put it in. Some say you would catch more blow by with it installed in the intake vent pipe and some say the PCV pipe. You would need to look inside your throttle body at the front vs the inside of your inlet manifold to see where there is more oil that needs to be collected.

Gavin

The vent that is connected to the intake pipe serves two purposes and is as follows...

In STOCK configuration when there is vacuum fresh filtered air is drawn into the crank case through the vent from the intake pipe and exits through the PCV valve into the intake manifold. This maintains a negative pressure in the crank case and carrys out moisture and any blow by gases thus preventing corrosion and sludge buildup in the crank case. When there is no vacuum and the PCV valve closes moisture and any blow by gases are drawn/forced out the vent in the opposite direction to what the fresh air was being drawn in. There is no fresh air or vacuum to help when the PCV valve is closed and that's most of the time.

So mine is stock with a tank in between, just to catch the blow by.

Gavin

My local Toyota dealer were handing these out today.

Thought I would share as I've never seen a Toyota one before...

Gavin

Yes u are correct however it is not as effective as using the vacum from the inlet and its illegal.

Yep! And it's illegal even with a catch can I would imagine.

Gavin