Catch Can Debate

[mad_sb]

Originally Posted by King Tut

Figured I would update you. I drained my catch can for the first time since I installed it in January. I have been boosted for a couple months now. It had about 8 ounces of the same looking liquid as this video:
...

It is mostly condensation mixed with oil.

I'm fairly sure the reason you have condensation in the can is because it is vented. On the last 3 turbo cars i ran closed catch cans on, i never once had any milky looking catch fluid drain out of the cans... just black oil.

[mad_sb]

Originally Posted by Hanakuso

Saikou Michi needs to release there setup soon..

I'm running two of their cans now and have been for a long while.. you don't need a specific setup, just get two dc3 cans and mount them where you see fit. I have one near the battery and one near the driver head light.

[mrk1]

Does anyone have long term experience with the clear hoses that companies like Cusco and ARC use?

I would think they would be useful during R&D but do they turn brown over time?

[xwd]

They do, you can get more at any hardware store if you really want to stay with clear ones.

[schtebie]

Originally Posted by mrk1

Does anyone have long term experience with the clear hoses that companies like Cusco and ARC use?

I would think they would be useful during R&D but do they turn brown over time?

Mine have already started to yellow a little bit and they've only been on just over a month or so.

Since the PCV outlet is smaller than the 15mm included in the Cusco kits, you'll have to find something smaller. I tried using the clear Cusco 9mm hose for that connection, but after a short 20-25 minute drive, it had completely collapsed from the force of the vacuum. (This shouldn't happen with the clear 15mm hose because it's reinforced with metal wire.)

[SuiSid3l]

Just a quick update to this thread

http://www.saikoumichi.com/DC3_page.htm

This what we're looking for in a dual catch can for the front and rear pvc?

[King Tut]

Originally Posted by King Tut

Figured I would update you. I drained my catch can for the first time since I installed it in January. I have been boosted for a couple months now. It had about 8 ounces of the same looking liquid as this video:

It is mostly condensation mixed with oil.

Figured I would update. I have drained my D3PE catch can another two times since this initial time. Both times there was probably a max of 2 ounces and it was more oil and less condensation. I am assuming that is due to the temps being warmer and closer to the temps of the air coming from the crankcase.

[Calum]

Originally Posted by mad_sb

Sounds like you have used similar setups in the past on other vehicles?

I'm not suggesting pulling a vacuum on the crank case will increase power, though i know lots of people make that claim and it doesn't take much consideration to understand the theory.. a piston traveling down the bore working against 20 PSI of pressure against the under side of the piston will have to work harder than a one moving through vacuum.

My preference is based on what i have observed on the dyno (dip sticks popig out, oil spewing all over the place, oil film covered engine bays, excessive oil smoke) and the theory behind why we have pcv systems in the first place (to prevent sludge buildup for one).

IMO the reason for a closed system is to scrub the oil vapor out of the crank case gases. If you had an open system that actually did that i think it would probably be superior to a closed system because you would not be re-circulating any of the other vapors.

Having vacuum in the crank case also aids in sealing the rings. The piston rings are sealed by differential pressure and maintaining a seal while the cylinder is on its intake stroke prevents fuel dilution in the oil. Something that wont be as noticeable in the catch can, but will have a negative effect on the oil. Better sealing rings also increases power and reduces blow by, thus reducing the need for a catch can.

I think I've said this before, but vented catch cans are a self fulfilling prophecy. When someone installs one they are allowing the engine to create more blow by thus making it seem like the catch can was needed in the first place.

[King Tut]

Originally Posted by Calum

Having vacuum in the crank case also aids in sealing the rings. The piston rings are sealed by differential pressure and maintaining a seal while the cylinder is on its intake stroke prevents fuel dilution in the oil. Something that wont be as noticeable in the catch can, but will have a negative effect on the oil. Better sealing rings also increases power and reduces blow by, thus reducing the need for a catch can.

I think I've said this before, but vented catch cans are a self fulfilling prophecy. When someone installs one they are allowing the engine to create more blow by thus making it seem like the catch can was needed in the first place.

I forgot to reply to this. I understand the benefit of pulling a vacuum on the crank case, but the issue I have is that at the times when this would be most benefitial, WOT, there is no vacuum being pulled, so it is just like if it was vented.

[Calum]

Originally Posted by King Tut

I forgot to reply to this. I understand the benefit of pulling a vacuum on the crank case, but the issue I have is that at the times when this would be most benefitial, WOT, there is no vacuum being pulled, so it is just like if it was vented.

The same thing happens with an NA engine. The vacuum in the manifold goes close enough to atmospheric pressure to be negligible while at WOT.

The question comes down to how much of the engine's running time is spent at WOT. Even a trailor queen race car probably doesn't see more then 60% actual wide open throttle use. A street car with as much power as yours is making, that gets tracked a few weekends a year, still probably doesn't go WOT for more then 10% of it's run time.

I just don't get why people in your situation wouldn't run a closed system so they can take advantage of the benefits of a PCV system the other 90% of the time. Even from a cost stand point, running a vented system should have you changing your at least oil twice as often as a closed system would, thus making the closed system more cost effective.

I wonder if anyone has sent oil samples off for testing to compare the effects of a vented system to a closed system?

Also, would you happen to know what the vacuum at the inlet to your turbo is while at WOT? I'd imagine it's pretty close to atmospheric as well but I've never measured one and I've seen a couple posts lately where people have mentioned using that as a vacuum source.

[King Tut]

Originally Posted by cjsporl

When i was talking to PERRIN a few days ago they said they are working on a catch can. PERRIN's prices arn't too bad compared to many of its competitors.

Do you have any details on what style it will be?

[Rosticles]

Thread Revive!

I have made some drawings depicting what I understand to be the standard dual can setup followed by two systems that I think would work well for a forced induction setup that doesn't have the intake port. Please let me know If I have misunderstood something, or if my proposed setups are shit, and why. Thanks.







Low Load: PMAN < Atmosphere, ValveMAN = Open, ValveVTA = Closed

This state allows the manifold to pull a vacuum on the PCV valve as the system would in a stock or dual can arrangement.

High Load: PMAN > Atmosphere, ValveMAN = Closed, ValveVTA = Open

The system in this state converts to VTA catch can arrangement. It will allow the crankcase to breathe without having to fight the boost pressure in the intake manifold.

My first thought is that I may have too much PCV blow by in the high load state. I don't know if crank case pressure increases semi-linearly with boost or just load.



Is the vent can even necessary? I've seen some members run it strait to a filter, but would love to know if anyone is collecting anything other than condensation in there.

[mit_peid]

I have a single can only on the PCV side and noticed this morning that it is actually doing something. Worthwhile $100 investment I think.

[King Tut]

Originally Posted by Rosticles

Is the vent can even necessary? I've seen some members run it strait to a filter, but would love to know if anyone is collecting anything other than condensation in there.

I think your plan would work, it should give the advantages of both systems all in one. Generally a filter is used to catch that last bit of oil in the air as it leaves the VTA catch can. The majority of the oil should be caught in a properly designed catch can.