S13 KA24DET correct oil catch can & PCV setup

[supra33202]

zer...et-uphttp://forums.nicoclub.com/z ... er...age=1

I want to install Circuit Sports (CS) Mini Style Oil Catch Tank (250cc) to my KA24DET.

http://www.frsport.com/Circuit....html

Nissan 240SX Silvia S14 S15 SR20DET Air Intake Systems

http://cgi.ebay.com/ebaymotors...ories

After reading all those threads, I am still confused.

Could you confirm the following is the correct way to setup oil catch can & PCV?

PCV valve -> oil catch can -> one-way check valve -> pre-turbo intake

Basically in stock setup, PCV valve (one-way check valve) will vent oil/air to intake. Since there is oil in the blow-by, we want to use catch can to catch the oil but let air go through. This prevents dirty the air intake piping. The one-way check valve is to make sure the air will not go back to PCV valve under boost.

Am I understand it correctly?

Please bear with me as I am very new to turbo/PCV/catch can.

Thanks!

[WDRacing]

You've got it. The oil/air separator simply goes between the pcv and the intake manifold. There's one vac line that goes from the pcv to the bottom of the intake manifold. Install the separation between those two and you'll be golden.

WD

[neverlift]

ok, instead of starting a new thread....

I installed a oil/air separator (from h/f), but it sucks air under vac, dont know about on boost lil confused... I'll be adding a couple check valves in the morning...

[supra33202]

You've got it. The oil/air separator simply goes between the pcv and the intake manifold. There's one vac line that goes from the pcv to the bottom of the intake manifold. Install the separation between those two and you'll be golden.

WD

Do you think this 15MM check valve will work with Circuit Sports Oil Catch Can?

https://www.freshwatersystems.....aspx

Thanks!
Modified by supra33202 at 9:09 AM 7/22/2009

[WDRacing]

Google boost check valves, or boost PCV valves and you'll come across tons of options. What you want is any inline check valve that will work inconjunction with the stock PCV so that NO boost pressure gets into the crankcase.

WD

[supra33202]

Google boost check valves, or boost PCV valves and you'll come across tons of options. What you want is any inline check valve that will work inconjunction with the stock PCV so that NO boost pressure gets into the crankcase.

WD

I re-read the post zer...et-up

Do you think the followings will work with Circuit Sport Catch Can with 15mm (15mm = 3/8") connectors?

Brass Medium-Pressure Spring-Loaded Piston Check Valves Female X Female 3/8" (QTY 1)http://www.mcmaster.com/#7775k53/=2uvn1t

Barbed Tube Fittings male 3/8" to tube 3/8" ID (15 mm) (QTY: 2)http://www.mcmaster.com/#5670k83/=2uvov0

I still have one more question. What do I do with valve cover breather connection?

I think other people do:

Tee connection between pcv valve and the valve cover breather -> oil catch can -> pre-turbo intake

I think you said this is wrong because the blow-by air/oil will go to back to the motor through the valve cover breather connection under boost. The catch can will do nothing in this case.
Modified by supra33202 at 11:32 AM 7/22/2009

[WDRacing]

Well, the best way would be to run an additional catch can between the valve cover breather and a bung placed pre-turbo. This pulls "some" blowby when under boost. But you need a catch can or you'll have oil mist all through the intake and FMIC.

I'd just use a breather filter.

I'm installing a header mounted evac system on mine and doing away with the factory system all together. The idea of having oil mist going to the intake is something I will never agree with.

WD

[supra33202]

Well, the best way would be to run an additional catch can between the valve cover breather and a bung placed pre-turbo. This pulls "some" blowby when under boost. But you need a catch can or you'll have oil mist all through the intake and FMIC.

I'd just use a breather filter.

I'm installing a header mounted evac system on mine and doing away with the factory system all together. The idea of having oil mist going to the intake is something I will never agree with.

WD

After reading http://www.106rallye.co.uk/mem...s.pdf, would this a better setup?

PCV valve -> one-way check valve

valve cover breather -> one-way check valve

Tee connection between the one-way check valve (pcv valve) and the one-way check valve (valve cover breather) -> oil catch can -> pre-turbo intake

Basically, both PCV valve and valve cover breather will go back to pre-turbo intake. This will insure proper idle and tuning. The one-way check valves are to insure the "bad" air/oil go back to motor directly. The single catch can will catch "bad" oil from both PCV valve and valve cover breather.

[supra33202]

http://www.nicoclub.com/forums...90544

I found a discussion regarding hollow vs internal baffling.

It seems like this is a good baffle catch can. I think this is what you said the best solution.

Saikou Michi Dual Chamber Catch Can *Evolvd*http://www.saikoumichi.com/SPLIT_DC3_page.htm

http://www.saikoumichi.com/product_line.html

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

[480sx]

The PCV system is so misunderstood.

PCV system - Removes blowby gases out of the crank case before it pollutes the oil. Spun bearings from excess gas in the oil over time is the #1 killer of a running well built boosted car.

Stock PCV system - Pulls air from the valve cover breather back into the intake manifold with full engine vacuum at idle through the PCV valve at 20 hg.

Your PCV system - Take that whole system and puts it to the pre turbo intake. The pre turbo intakes do not have the ability to produce much more than 2-3 HG of vacuum, and this is under extreme circumstances during full/high boost. At idle, you have no PCV system, where as with a stock setup you have the max PCV system of 20hg against the crank case. During cruising you would be lucky to pull 1 HG of vacuum. So basically, you have a PCV system that works 10 times worse than the stock system, and only really works that well when your in FULL BOOST.

[supra33202]

The PCV system is so misunderstood.

PCV system - Removes blowby gases out of the crank case before it pollutes the oil. Spun bearings from excess gas in the oil over time is the #1 killer of a running well built boosted car.

Stock PCV system - Pulls air from the valve cover breather back into the intake manifold with full engine vacuum at idle through the PCV valve at 20 hg.

Your PCV system - Take that whole system and puts it to the pre turbo intake. The pre turbo intakes do not have the ability to produce much more than 2-3 HG of vacuum, and this is under extreme circumstances during full/high boost. At idle, you have no PCV system, where as with a stock setup you have the max PCV system of 20hg against the crank case. During cruising you would be lucky to pull 1 HG of vacuum. So basically, you have a PCV system that works 10 times worse than the stock system, and only really works that well when your in FULL BOOST.

So what is your suggestion?

[supra33202]

http://cgi.ebay.com/ebaymotors....m245

After reading

http://forums.evolutionm.net/e....html

and

http://forums.maxima.org/super....html

, I think this setup might work better when under boost.

"Your method is not going to work well. The reason being is that your forgetting that our car has a maf. So any extra air comming in after the maf is going to cause drive-ability and or idling issues.

You have to do one of the following:

Keeping stock setup but running a catch can.

or

What I am doing, venting to atmosphere with intake manifold plugged and intake tube plugged to prevent outside air from getting in unmetered.

The breather filters might get some oil vapors because of oil vapors with the blow by gas. But you could get one of those catch cans that are not seald and have a breather on them. This would then have a place for some oil vapors to collect.

Remember the stock pcv line system is designed for emissions reasons while releiving the crank pressure. Since we all mod our cars, run no cats/hfc's, etc... We are breaking the rules anyways. So there is no point in keeping the factory routing. Also catch cans dont work 100% this is the only 100% true bone dry method of ensuring absolute Zero oil in the intake. With the assumptions everything is running properly." - by BluEVOIX

My new setup:

PCV valve -> oil catch can with breathervalve cover breather -> oil catch can with breather

Don't use the pre-turbo intake connection at all.

Pro

- No need to worry vacuum leak (unmeasured air goes after to MAF); good for tuning- When under boost, the PCV valve and valve cover breather can vent those air/oil to the oil catch can freely. The internal air pressure is much higher than the atmosphere pressure. PCV system works properly.

Con

- During idle/non-boost condition, the PCV valve will not have enough pressure to vent those air/oil to the oil catch can. PCV system doesn't work properly.

My previous setup:

PCV valve -> oil catch can -> one-way check valve -> pre-turbo intakeValve cover breather -> breather filter

Pro

-Under idle condition, the airflow from the pre-intake helps sucking those air/oil from PCV valve. PCV system works properly.

Con

-Under boost condition, alot of air will flow back to the motor through the pre-turbo intake, and the PCV valve and one-check valve will shut. The air/oil will be stuck inside the motor, so my PCV system doesn't work properly.

If we were just worrying about boost condition, new setup should work better, right?

[JohnsS13]

I am working on this right now too, and I think what Im going to do is just put a fitting into the little aluminum box in place of the PCV valve itself, and run a line from the fitting on the box to a catch can with an atmospheric vent.

The valve doesn't really seem necessary to me since the point of the whole system is to vent crankcase pressure. The valvecover has baffles in it to condense oil up there, so Im either going to just put a small breather on it or T it into the same line going to my catch can from the PCV valve location.

(valvecover)---->T--->(catch can)--->vent(former pcv)-----^

EDIT: I understand that there won't be a vacuum on the system to pull gases out, and this will make my oil go bad faster but I'll just change it more often than normal.

[WDRacing]

I'm sorry I have to disagree with your entire plan.

You identified the main issue, no vacuum in the crankcase. That's actually a huge problem if your car is boosted. Since you get 3-4 times the amount of blow-bye when on boost compared to NA. That will ruin your oil fairly quickly and changing it often is just not a good idea. Especially when the fix is a vacuum line away.

Can't remove the PCV because it's a check valve to keep boost out of the motor. But since you're not going to do this setup anyway...right...it won't be an issue.

The breather filter is ok.

WD

[JohnsS13]

oops stupid question.

[supra33202]

After reading honda and other people regarding PCV setup, I think the best solution is to connect PCV valve and valve cover breather to exhaust. In case, you don't want to leak oil on the road/track, connecting a catch can in between PCV valve and exhaust is a good solution.

Pro:1) No need to worry about vacuum leak/tuning (no unmeasured air goes after to MAF).2) Will have good vacuum in boost and idle/non-boost situation.

Con:1) More complicated and expensive

To most people, venting PCV and valve cover breather to atmosphere is good because no need to worry about tuning. And most people claim that will work but it is not the best solution.

[TrukillaS14]

ok since u went through the forums already I wanted to ask, why do some people have a filter at the top wat does that do for the oil catch tank

[supra33202]

ok since u went through the forums already I wanted to ask, why do some people have a filter at the top wat does that do for the oil catch tank

Blowby comes out from both the PCV connection and valve cover breather connection.

The valve cover breather filter is used to protect dust to go inside the engine.

Putting the valve cover breather filter filter at the top will vent the blowby to the atmosphere. Some say it is not effective since there is no vacuum, and some say it is ok since most blowby comes off from PCV connection.

Some people said they have blowby/engine oil coming off from the valve cover breather filter, and it dirties the engine bay, so they put an oil catch can to catch the oil. The other another end of the oil catch can go to pre-turbo intake for some vacuum under boost (some people said there is almost no vacuum at all). Some people said with oil catch can connected between the valve cover and pre-turbo intake, the blowby/engine oil will dirty the intake/turbo.

I actually asked the same question in this thread, and here is WD's answer.

"Well, the best way would be to run an additional catch can between the valve cover breather and a bung placed pre-turbo. This pulls "some" blowby when under boost. But you need a catch can or you'll have oil mist all through the intake and FMIC.

I'd just use a breather filter.

I'm installing a header mounted evac system on mine and doing away with the factory system all together. The idea of having oil mist going to the intake is something I will never agree with.

WD"


Modified by supra33202 at 9:38 AM 9/17/2009