Catch cans catch stuff

[mugsee]

Haha. This is why the whole catch can business took me a while before I decided on a way to set it up.

I was set on attaching up the catch can the method that Chi and Tinkerbell have suggested (PCV -> catch can -> IM) but after looking at pictures of the Spoon setup (and apparently a lot of other JDM setups), I started wondering why they always ran their catch cans to their valve covers.

eg:


My guess that Spoon and the other racing companies mounted their catch cans to their valve cover was because it was because excess gases were vented through the valve cover (I think I read that somewhere), hence why I've attached it to both places (PCV + Valve cover) within my setup.

Upon looking at a catch can setup on the Spoon CL7, it appears that they also have a hose coming off the PCV which I assume heads towards the catch can. Anybody know any more information on how they setup their catch can?

See this link for a pic of the Spoon CL7: http://forums.clubrsx.com/attachment...1&d=1104692613

Out of a matter of interest, when people disconnect the tube between the IM and the valve cover and attach a breather filter, does that filter usually becoming oily and dirty?

[tinkerbell]

what is the systems' intended purpose? containing the "bad" gases/fluids?

it is an emmissions control device.

but also helps keep oil fresh under harsh high temp conditions (like racing) and helps evacuate excess crankcase pressure (like when racing)

but an emmissions oriented PCV system is MUCH different to a race PCV system...

finding the compromise for a street car is difficult.

[tinkerbell]

So back to the topic thread, the way Mugsee has set up his catch can would deem incorrect?

totally incorrect, the crankcase is connected directly to the intake manifold...

EDIT: unless i totally misinterpreted his explaination of it...

maybe MS Paint diagram will help?

[mugsee]

The way I set it up was because I thought the valve cover would vent vapors to the atmosphere however this doesn't appear to be the case.

If the valve cover is actually drawing air in, then the catch can setup I have is incorrect.

I think I'll do a bit more reading around on this.

[tinkerbell]

why have you decided to change it in the first place? make sure you resolve that issue, without creating new ones...

[mugsee]

Oh, if it makes it any clearer:

valve cover -> catch can -> intake
PCV -> catch can - > intake

[Chi]

But are you 100% sure the rocker cover is not sucking in?

Because if it is, then the gases from teh PCV is going into the engine before it even goes near the catch can.

I am not a big fan of alot of spoons mods and parts as I have found alot of their products to be useless or to be inferior to many other designs.

[Wlee2]

But are you 100% sure the rocker cover is not sucking in?

Because if it is, then the gases from teh PCV is going into the engine before it even goes near the catch can.

I am not a big fan of alot of spoons mods and parts as I have found alot of their products to be useless or to be inferior to many other designs.

im going to stay out of this for now.. since me and tom already had this discussion =P..

but if the rocker cover is sucking in and lets say what chi said the gasses is going into the engine before it goes near the catch can? then why did it catch something?

he was ment to go out to the car with some sort of Rubber balloon to see if it deflated or inflated =P (he suggested one of the rubber products he had lying around the house)....

[Chi]

im going to stay out of this for now.. since me and tom already had this discussion =P..

but if the rocker cover is sucking in and lets say what chi said the gasses is going into the engine before it goes near the catch can? then why did it catch something?

he was ment to go out to the car with some sort of Rubber balloon to see if it deflated or inflated =P (he suggested one of the rubber products he had lying around the house)....

it caught something but was it what you wanted to catch?

He said he has tracked , and I assure you I have seen many cars with catch cans set up the way i thought was right and they caught oil not looking like that.

[Wlee2]

it caught something but was it what you wanted to catch?

He said he has tracked , and I assure you I have seen many cars with catch cans set up the way i thought was right and they caught oil not looking like that.

umm the oil color is because he didnt clean it up after dousing the whole thing with degreaser..

and oil and degreaser looks like that brown gunk =P try it sometime =P

[Chi]

If you look at some of teh airbox designs on the inside you can see some grooves created to flow into the rocker cover connection.

A test I've done was place a big A4 piece of paper in front of the hole and the paper was being drawn in now blown out, Im jsut curious to see if you have actually tested it with the engine running.

Another thing is, I have had a few friends use GruppeM intakes on the DC5 and the red hosing that goes to the rocker cover and intake never has oil or massive amounts of gunk built up inside it.

[Wlee2]

A test I've done was place a big A4 piece of paper in front of the hole and the paper was being drawn in now blown out, Im jsut curious to see if you have actually tested it with the engine running.

Have you ever tried the same thing on the hole on the air intake arm?

moving air from high pressure to low pressure causes a vacuum

as the air molecules are taken into the engine it creates a vacuum in the intake arm (less air molecules in the arm)

the arm then tries to Equalize the vacuum caused by Drawing more air from the end of the arm (filter)

if you added a hole along the intake arm would it not also create a vacuum as the air is constantly been sucked into the engine?

is this vacuum there (like in stock cars Valve to Intake arm) somewhat negate each other if the valve does infact have a slight vacuum?

but if the air pressure in the valve cover is greater than the air pressure in the intake arm the air will flow from greater -> lower

if its a lower pressure (vacuum only compared to the intake arm) then it will flow from intake arm to valve.

now when you put your Piece of paper theory to the test you tested it VS GASp Atmospheric pressure.. .. ..

is that necessary the same if its VS the intake arm while air is moving?

is it not wrong to say that if you created a stronger vacuum om the apposing end of another "vacuum" the air would move from high presure to low pressure.?

im still trying to work out why mugsee caught something if the valve cover you said indeed has a stronger vacuum..

[Chi]

You ahve a valid point there.

Just curious about idling wise, since its such a bigger distance in that set up for the intake to provide a opposing vaccuuming source to the rocker cover if itll draw the stored up blow by gases into the can.

Might be a better idea to have 2 seperate connections from the Rocker cover and the PCV to the can?

[BlackDC2]

use fuel foam to baffle your catch cans!!!

[tinkerbell]

Have you ever tried the same thing on the hole on the air intake arm?

moving air from high pressure to low pressure causes a vacuum

as the air molecules are taken into the engine it creates a vacuum in the intake arm (less air molecules in the arm)

the arm then tries to Equalize the vacuum caused by Drawing more air from the end of the arm (filter)

if you added a hole along the intake arm would it not also create a vacuum as the air is constantly been sucked into the engine?

constantly? i.e. WOT???

nah, most of the time the throttle plate is closed isnt it?

which is when highest VAC is in IM, so that is the VAC source for the PCV system.

the intake air provides a source of clean air, as it may end up in the combustion chamber...

is this vacuum there (like in stock cars Valve to Intake arm) somewhat negate each other if the valve does infact have a slight vacuum?

not sure what you are talking about?

but if the air pressure in the valve cover is greater than the air pressure in the intake arm the air will flow from greater -> lower

if its a lower pressure (vacuum only compared to the intake arm) then it will flow from intake arm to valve.

but the pressure in valvecover is higher due to being attached to the intake manifold, isnt it?!

now when you put your Piece of paper theory to the test you tested it VS GASp Atmospheric pressure.. .. ..

is that necessary the same if its VS the intake arm while air is moving?

is it not wrong to say that if you created a stronger vacuum om the apposing end of another "vacuum" the air would move from high presure to low pressure.?

im still trying to work out why mugsee caught something if the valve cover you said indeed has a stronger vacuum..

the valve cover has vacuum via the intake manifold.

simple.

(except maybe at WOT, which is when the PCV valve CLOSES anyways)