Catch cans catch stuff

[tinkerbell]

I think this discussion would go a little better with a few pictures

a honda system, EG civic - note the arrows!

[Wlee2]

that is why the PCV valve is tehre - to SHUT at WOT so no oil vapours get into the intake manifold...

i am so lost now..

if the PCV closes during WOT.. the oil that would have normaly escaped wont?

and if the PCV is closed at WOT what use is an oil catch can if you bung it in between the PCV and the crank case? aint we trying to catch the oil before going to the intake manifold? (i say this because we closed off the PCV valve)

from what i understand... of what tinks said if the valve is closed then.. theres no chance of oil going into the intake while in WOT..?

*scratches head*...

[ChargeR]

highest combustion chamber presasure means you DONT wantr any oil vapours as thes lower octane...

BOOOOM!

that is why the PCV valve is there - to SHUT at WOT so no oil vapours get into the intake manifold...

I dont disagree that having the crankcase vapours venting through the PCV valve at wide open throttle is a bad thing but how does the valve prevent this? The pressure in the intake manfifold will be at it's highest at wide open throttle, however I would think that the pressure in the crankcase would still be enough to open the PCV valve.

Is the PCV valve not simply a spring loaded one way valve designed to allow gases to flow only from the crankcase to the intake manifold and not the other way?

Or are you suggesting that the spring preload in the one way valve is perfectly set up so that the crankcase pressure in a normal honda engine will be insufficient to lift the seat of the valve when there is the manifold pressure of wide open throttle on the other side?

Or am I on completely the wrong track here .

[tinkerbell]

I dont disagree that having the crankcase vapours venting through the PCV valve at wide open throttle is a bad thing but how does the valve prevent this? The pressure in the intake manfifold will be at it's highest at wide open throttle, however I would think that the pressure in the crankcase would still be enough to open the PCV valve.

Is the PCV valve not simply a spring loaded one way valve designed to allow gases to flow only from the crankcase to the intake manifold and not the other way?

Or are you suggesting that the spring preload in the one way valve is perfectly set up so that the crankcase pressure in a normal honda engine will be insufficient to lift the seat of the valve when there is the manifold pressure of wide open throttle on the other side?.

yes, it is designed to...

under normal road conditions,

in racing, the rpm is so high that your concern is pressure evacuation, not emmissions, plus you should remove the inlet to the manifold and run and open system... to ensure that blowby cant get near the combustion chamber.

i.e. mugsee needs to get rid of the line to the inlet manifold, remove thew PCV valve and run a line from the valve cover and the PCV valve location to the baffled catch can.


sorry to side track it on which way the air flows guys, my bad

[mugsee]

Thanks to all for the good discussion.

Before we initially setup the catch can I read both sides of the story about whether the valve cover sucks or dispells which was why I thought I'd opt to have the best of both worlds (PCV + valve cover), which is why I ended up with the current setup.

Tinkerbell, what would the difference in a race setup be to warrant catching vapours from the valve cover instead of the PCV?

[tinkerbell]

Thanks to all for the good discussion.

Before we initially setup the catch can I read both sides of the story about whether the valve cover sucks or dispells which was why I thought I'd opt to have the best of both worlds (PCV + valve cover), which is why I ended up with the current setup.

Tinkerbell, what would the difference in a race setup be to warrant catching vapours from the valve cover instead of the PCV?

the valve cover has the biggest sized orifice, so you would use that for a race setup...

like the spoon dc5 picture above...

[mugsee]

i.e. mugsee needs to get rid of the line to the inlet manifold, remove thew PCV valve and run a line from the valve cover and the PCV valve location to the baffled catch can.


sorry to side track it on which way the air flows guys, my bad

When you get time, could you explain the proposed setup a bit further? Is it: PCV -> catch can -> valve cover?

Also the airflow discussion is good. It ties in with Chi's original question that I couldn't answer. Heres something I found on HT that explains the valve cover airflow in a bit more detail. See test 2 in particular.

http://www.honda-tech.com/zerothread?id=697498

[ChargeR]

Just so everyone is clear because I don't know whether it is obvious from the photo. This is how mugsee's catch can is hooked up:



The original vacuum source on the intake manifold is plugged.

[tinkerbell]

well i thought the line that is going from the T junction towards the engine was to the inlet manifold..

where is the line from the catch can to the inlet pipie attached to the catch can???

any pictures of the actual catchcan close up?

[Wlee2]

With this in mind, the catch can setup I have retains the intake vacuum source to suck in the air/oils into the catch can, and is connected to the valve cover and the PCV, which it draws the excess air/oil from.

That black tube connects to the intake pipe of Mugsee's Injen.

well i thought the line that is going from the T junction towards the engine was to the inlet manifold..

where is the line from the catch can to the inlet pipie attached to the catch can???

any pictures of the actual catchcan close up?

???

[tinkerbell]

EDIT: n/m i found it... i did not see the black hose near the headlight before, pretty fucking dumb of me wasnt it...

you may as well remove that, and put a breather filter on it?

then it will be perfect.

[Wlee2]

Just so everyone is clear because I don't know whether it is obvious from the photo. This is how mugsee's catch can is hooked up:



The original vacuum source on the intake manifold is plugged.

although i like this design.. i wonder if a Diy should be made to modify the catchcan to do this.. is it better ?

[tinkerbell]

PCV valve should be removed and fitted with an open fitting... as large as possible. to run a large a line as possible.

the line to the intake pipe should be removed and replaced with a breather filter - then it will be a pproper 'race' setup...

yes, wayne, that is how it should go, as freely as possible...

[Wlee2]

PCV valve should be removed and fitted with an open fitting... as large as possible. to run a large a line as possible.

the line to the intake pipe should be removed and replaced with a breather filter - then it will be a pproper 'race' setup...

yes, wayne, that is how it should go, as freely as possible...

everyone agree?

[e240]

remove all canisters and filters, pipe from the rocker cover should be extended to the front of the car, pipe from the back of the block should exit from the rear. That way, you have one pipe sucking the car forward and one pipe pushing the car forward.
We call this Transwarp drive...