1G PCV System Question

[Kapok6]

I have some questions about modded crank case ventilation systems. On my previous motor I built years ago, I was foolish, and only had your typical two stock sized lines from the valve cover to a cheapo catch can that vented to the atmosphere. Well, I produced oil leaks pretty quick and was blowing the dipstick out any time I got on it.

So I started to research and ended up doing a system nearly identical to Paul Volk's. Two -10AN's from the valve cover to a sealed catch can, (Calan), then from catch can to turbo intake pipe with a -12an. My dipstick stopped blowing out and my oil leaks went away. Yippee.

Fast forward to now, with my new motor. I put the same system back on, with one small mod, I incorporated what Jacks did, (http://www.jackstransmissions.com/pages/jacks-pcv) by adding a line from the stock PCV valve to the intake manifold. From the moment I turned the key for the motors first start up, it idled perfectly, and has ran GREAT for the last 500mi. No oil leaks, dipstick does NOT move, etc. Rings sealed in the first 10mi of beating the piss out of it. No Smoke whatsoever after the first 10mi.

But this got me thinking, how are guys getting away with running just two lines to a vented catch can with no connection to a vacuum source and not having ventilation issues? For instance the guys with forward facing turbos and no intake pipes or filters? Is crank case pressure not an issue if you have good ring seal, and as such, have no need to run a line to a vacuum source?

The reason behind me asking this is that I am wondering if once the rings are sealed, can someone like me just eliminate the turbo intake pipe and the line running to it from the catch can with no ill affects?

 

[TexasTurbo]

They're getting away with it because the PCV wasn't your issue. If you have a beat oil leaking motor it's going to leak no matter what you're doing with your PCV. The big boys running race cars are likely using vacuum pumps for the crank case. Too easy.

 

[Kapok6]

Really? Because when I revamped my PCV system, all oil leak issues went away with no other modifications. And "Probably" is nothing more then speculation, certainly not a definitive answer.

 

[TexasTurbo]

Well feel free to research what people making horsepower do... I mean, you're on the internet. Muscle cars have been using vacuum pumps for decades. You had problems with your oil leaks because you modified what the mitsu engineers designed. Maybe reading forums lead you to this "answer" that ended you up with a non functional PCV system that you later returned to a "stock" style setup.

The clear answer is that those guys either don't care because it's a race dedicated vehicle.... OR they're using a vacuum pump. There's no magic to it.... but maybe you can find the answer you're looking for by asking rather than researching.

 

[hakcenter]

I'm there with my truck, I'm tired of an under carriage collecting dust and grease cause it can, so I revamped my crank case venting.

I've had exhaust vacuum dump and turbo ingestion.

I would imagine guys running high power just don't care for the relatively short amount of time the motor is actually under power, is 7-10 seconds.

Unlike those people you drive your car more than a quarter mile at a time so you actually see these issues, long pulls on the freeway etc.

One thing to note is that recirculating your blow by inadvertently lowers your octane, big fuel isn't going to care and the ring seal is going to help you make even more power.

I've considered trying to retro fit the gear driven vacuum pump on my truck, to vent to atmosphere but yet draw from crank. Maybe once I take it off I might come up with a solution.

 

[Kapok6]

I'm there with my truck, I'm tired of an under carriage collecting dust and grease cause it can, so I revamped my crank case venting.

I've had exhaust vacuum dump and turbo ingestion.

I would imagine guys running high power just don't care for the relatively short amount of time the motor is actually under power, is 7-10 seconds.

Unlike those people you drive your car more than a quarter mile at a time so you actually see these issues, long pulls on the freeway etc.

One thing to note is that recirculating your blow by inadvertently lowers your octane, big fuel isn't going to care and the ring seal is going to help you make even more power.

Lastly, I haven't seen a single DSM with a vacuum pump so to assume anyone making big power is using one is stupid. Mr Polk obviously isn't using one. Nor is Mr Ryan, both people have proven vehicles substantially faster than any car you've ever owned or built and they don't run pumps.

I've considered trying to retro fit the gear driven vacuum pump on my truck, to vent to atmosphere but yet draw from crank. Maybe once I take it off I might come up with a solution.

That makes sense as most of the high power DSMs I have seen running without intake pipes and vented catch cans are pretty much race only. Not vehicles taking 100mi cruises on the weekends.

I have also been thinking about what you mentioned above about how having it set up like I do, as well as Mr. Volk and Jack over at jackstransmissions, where the crank pressure is being recirculated back into the intake system lowering octane. Kiggly was actually just discussing this a couple weeks ago. He was seeing more knock with an FMIC than he was without one. Turns out there was oil build up in his IC, and its doesn't take much oil to lower octane.

That being said, it looks like for a majority of us, there are only two options. Full race and just deal with the blow by, or eliminate blow by but have a lower octane rating due to oil in the intake system.

The other way around this could possibly what you and I have discussed in the past; having the crank case pressure vent into the exhaust like V8 and some supra guys have been known to do, basically letting the exhaust create the vacuum needed. If it was set up in a manner that works, that would obviously allow you still pull pressure from the crank case, while not having an affect on the octane value since no oil would be getting recirculated back into the system.

 

[hakcenter]

That makes sense as most of the high power DSMs I have seen running without intake pipes and vented catch cans are pretty much race only. Not vehicles taking 100mi cruises on the weekends.

I have also been thinking about what you mentioned above about how having it set up like I do, as well as Mr. Volk and Jack over at jackstransmissions, where the crank pressure is being recirculated back into the intake system lowering octane. Kiggly was actually just discussing this a couple weeks ago. He was seeing more knock with an FMIC than he was without one. Turns out there was oil build up in his IC, and its doesn't take much oil to lower octane.

That being said, it looks like for a majority of us, there are only two options. Full race and just deal with the blow by, or eliminate blow by but have a lower octane rating due to oil in the intake system.

The other way around this could possibly what you and I have discussed in the past; having the crank case pressure vent into the exhaust like V8 and some supra guys have been known to do, basically letting the exhaust create the vacuum needed. If it was set up in a manner that works, that would obviously allow you still pull pressure from the crank case, while not having an affect on the octane value since no oil would be getting recirculated back into the system.

Exhaust was working for me until the flapper failed, only way I noticed was dipstick popping out and oil at the valve cover bolts.

I need to relocate it further down stream maybe two into one with a y to increase flow. I've never noticed anything with the exhaust no build up, etc

 

[Kapok6]

Jon, can you put me in touch with someone who uses a vac pump for the purpose of crank case ventilation on a DSM? I'd like to pick their brain about their setup/application.

 

[gofer]

Keep the posts clean and answer the OP's question.

I don't know how you search this site without seeing any mention of Craig's CC but here's a link to it if you missed it somehow. http://www.jcsautomation.com/vs catch cans.html#VS3

I could explain it but it's all on the website.

 

[Kapok6]

Keep the posts clean and answer the OP's question.

I don't know how you search this site without seeing any mention of Craig's CC but here's a link to it if you missed it somehow. http://www.jcsautomation.com/vs catch cans.html#VS3

I could explain it but it's all on the website.

In my first post I stated I have a setup nearly identical to Paul Volk's, including one of Calan's catch cans; with one slight modification. So I'm not entirely sure why you are referring to searching this site in regards to Calans catch cans, when I have his product, and understand how they work.

My point of interest was how people with big turbos and no intake pipes/filters create vacuum for the crank case system as they obviously do not have an intake pipe to hook a line to. Most of the ones I have seen just have two lines off the VC to a catch can that is vented to atmosphere.

What I gather so far is:

1.) big turbo/power cars that don't run their system to a vac source deal with improper ventilation for the short amount of time their vehicle is being operated because racecar, and who cares about blow by; vent what you can through an open catch can, and forget the rest

2.) Street cars have a setup similar to mine, pauls, jacks, etc, and have reduced blow by related issues, at the cost of having some amount of oil/crank case gasses making it back into the intake system, and we just deal with the lower octane that results

3.) Have the exhaust system act as the vacuum source so you still get - pressure in the crank case instead of +pressure, and octane is not lowered because there is no oil/cranks case gasses being recirculated back into the intake system; similar to what have seen V8 and some supra guys do, (I haven't seen where this has been done on a DSM yet)

4.) Jon's theory that big power, big turbo DSM guys/gals use a vacuum pump to eliminate crank case pressure-for which I have not seen any examples or evidence provided

 

[TexasTurbo]

You guys are overlooking the fact that not everyone that's fast comes online to play keyboard cowboy on the forums. I don't know a single person that is aware of every DSM owner and can speak for all of them. The people on this site are not 100% of everyone that cares about these cars. Just because you haven't seen it doesn't mean it doesn't exist (think about your religion here) or that someone else has the duty to put effort into proving anything to you. I'd say any help you get here is a courtesy, not an opportunity to look a gift horse in the mouth.

I'll say it again, reworded, in an effort to get you to swallow the information and understand it:

If you're running a street legal street car, then hook your PCV up properly, possibly opening up the flow more than the factory has done and drive your car. If you don't want oil vapor lowering your octane then filter it out. The system needs vacuum on it, period..... PERIOD. However you get that introduced is up to you. Argue it if you want because so and so super hero dsm guy hasn't been running his properly either. He is, likely, very well aware of the issues it causes and may not care. I would stop comparing yourself to other people and speaking for those you don't know personally. Your car isn't their car and you're not them.

Race car - who cares.
Non race car - hook it up properly aka. don't vent to atmosphere. Incorporate a can in the system if you need it.

I've offered you an answer already about how the guys with no intake pipe are getting vacuum in their system. Look the other way and pretend that no dsm has a vacuum pump installed on it, I dunno. I think you guys just like to debate.... badly.

 

[Archer Fabrications]

I dont have issues running two stock lines to a gatorade bottle, but i plan to incorperate vac in the future,

If you wanted to get rid of your intake pipe you can always hook it up to the intercooler pipe woth a check valve..but when your in boost not sire what will be pullung the air out now that i think about it. So i guess exhaust would be a decent way, is there any way to pull vac from the egr?

Oh and ive been doing the gatorade bottle thing for 13,000 miles and have no leaks or issues. I rarely drive the car now a days.

 

[Kapok6]

I dont have issues running two stock lines to a gatorade bottle, but i plan to incorperate vac in the future,

If you wanted to get rid of your intake pipe you can always hook it up to the intercooler pipe woth a check valve..but when your in boost not sire what will be pullung the air out now that i think about it. So i guess exhaust would be a decent way, is there any way to pull vac from the egr?

Oh and ive been doing the gatorade bottle thing for 13,000 miles and have no leaks or issues. I rarely drive the car now a days.

Yeah, the intake pipe tap wouldn't really work as you pointed out. It would work half the time. But I also incorporated what jacks transmissions did with a line running from a stock pcv valve directly to the intake manifold, so vac is being pulled een when the turbo is not under load, which is essentially what tapping into and IC pipe would do.

As for your gatorade bottle setup; you have no oil leak or dip stick popping out issues? I have seen some get away with this setup, (I know a guy personally that runs something similar), but that method wasn't working on my motor a few years ago, hence why I changed it up.

 

[Archer Fabrications]

I'm not saying everything is good by any means. I just havnt had any problems yet. I'm sure I'd greatly benefit from vac, but at this time I'm using all my vac ports dedicated to where they go and no tee off's. I crimped the dip stick a little so it doesnt go anywhere and i use a -12 turbo drain. And i dont get more than 1/8-1/4 inch blowby in the bottle. The car stopped being a daily in winter 2013, and now it's primairly a track/weekend warrior when it's mot under the knife.
So in regards to what texas turbo said, because race car, i dont really care right now, but i plan to do something about it some day. i really suck at /hate welding oily cast aluminum so i havnt dont the valve cover ports, but ive considerd also venting from the billet oil cap that is offered by a member on here. Or ponying up for a front line or magnus valve cover.

Now if i had an extra vac port laying around i would do it like a stock system but use a catch can, and larger lines. One to intake manifold, and other to inlet pipe, which I'll retain cause I'm top mounted. And i like turbo saftey


Why dont you just try a vac pumo for yourself? Couldnt be that hard to setup...

 

[TexasTurbo]

I told you Kapok that it's because you had a leaky engine. The non vacuum setup likely wasn't helping your leaky motor hold oil in and when you switched to a vacuum setup it likely was just leaking less.

Let me help you (even more) by googling for you:

https://www.google.com/search?q=crank+case+vacuum+turbo+car&ie=utf-8&oe=utf-8

-> 1st link

http://www.yellowbullet.com/forum/showthread.php?t=411303

Looks like a few guys there pulling some fast times in their cars are recommending to use a vacuum pump. Problem is, they're expensive. You can either try to cheat what the engineers put on the car by running it some other way... or you can improve what they were trying to do, on a car that has more blow by, by adding a vacuum pump. Debate about it on the internet all you want but the time won't be spent on your car fixing your problem.

If you have PCV problems I feel bad for you.

 

[TexasTurbo]

"Lots of people run vented systems for simplicity (or lack of understanding), but pulling a vacuum on the crankcase is ALWAYS a better option. More than anything els,e it helps promote good ring seal.


You have a few options really, depends on how 'oem-like' you want it to be. You can try to optimize the OE system, or you can run a hose from the valve cover to a catch-can, and then to a vacuum source. You've got a couple options there. You can run the catch-can line to the pre-turbo piping, but thats not recommended, as you may oil-soak your turbo and intercooler/piping. Another proven option is with an exhaust check-valve. It uses a venturi effect to draw a vacuum at all times, and that vacuum increases with increased airflow (basically, as power rises, exhaust gas volume roses, as does the amount of vacuum being created). Now, that doesn't always mean you'll have 100% vacuum at all times. Depending on how lose your motor is built, or how much ring blow-by you have, the vacuum method may simply be trying to overcome those positive pressures and you may end up with only a couple inches of mercury of vacuum. Still, it's better than none

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"

--more info found easily on google.

 

[Kapok6]

I'm not saying everything is good by any means. I'm sure I'd greatly benefit from vac, but at this time I'm using all my vac ports dedicated to where they go and no tee off's. I crimped the dip stick a little so it doesnt go anywhere and i use a -12 turbo drain. And i dont get more than 1/8-1/4 inch blowby in the bottle. The car stopped being a daily in winter 2013, and now it's primairly a track/weekend warrior when it's mot under the knife.
So in regards to what texas turbo said, because race car, i dont really care right now, but i plan to do something about it some day. i really suck at /hate welding oily cast aluminum so i havnt dont the valve cover ports, but ive considerd also venting from the billet oil cap that is offered by a member on here. Or ponying up for a front line or magnus valve cover.

Now if i had an extra vac port laying around i would do it like a stock system but use a catch can, and larger lines. One to intake manifold, and other to inlet pipe, which I'll retain cause I'm top mounted. And i like turbo saftey


Why dont you just try a vac pumo for yourself? Couldnt be that hard to setup...

I actually did hook a vac pump to try to eliminate crank case pressure a long time ago. The pump worked as it should but pulled WAY too much vacuum. So much it was pulling oil through the turbo and oil actually started leaking out of the hot side of the turbo/o2 housing. -24HGin is just too much. If you could regulate it to maybe -7HGin, it may be feasible, but as it is, just slapping an Audi vac pump on to draw vacuum from the crank case is overkill. The good thing is, the current motor I just built has been absolutely perfect with the Paul/Jack hybrid style system.

 

[CrackedDSM]

I actually did hook a vac pump to try to eliminate crank case pressure a long time ago. The pump worked as it should but pulled WAY too much vacuum. So much it was pulling oil through the turbo and oil actually started leaking out of the hot side of the turbo/o2 housing. -24HGin is just too much. If you could regulate it to maybe -7HGin, it may be feasible, but as it is, just slapping an Audi vac pump on to draw vacuum from the crank case is overkill. The good thing is, the current motor I just built has been absolutely perfect with the Paul/Jack hybrid style system.

I wonder if there would be a way to, cost efficiently, limit the vacuum to -4 to -7 region. I wanted my motors tolerances built a little on the loose side for the reason buschur does all of his motors(mine aren't nearly as loose as his though), so if you say your Volk/Jack's hybrids works, I may try that setup. I think you should keep the intake pipe on though. 140+mph traps on full street car status.

 

[hakcenter]

Its difficult to find a flawless system. Everything has its draw backs, belt setups or low / high draw.

I really liked my exhaust setup it just plainly works.

The big deal is to have a system that is engine speed dependant that you don't have over draw and pull oil in the wrong places.

Intake draw for you is not so good but its a gnomer issue for me (diesel).

I don't think a vacuum pump on a dd is the way to go unless you don't care about mpgs.

 

[CrackedDSM]

I don't think a vacuum pump on a dd is the way to go unless you don't care about mpgs.

I'm with you. It'd be like putting a mechanical fuel pump and a stock DSM SMIC filled with water as an intercooler on a less than 20g powered DSM, doesn't really make sense.

 

[Kapok6]

I will most likely just continue roll with what I have now on this car, then on the other one when I actually build it, I may try something different. I certainly won't be trapping 140 on this turbo though. I'm cool with the low 130's I got on this car. The other one...we will see.

 

[Kapok6]

I'll just need to make sure to clean out the IC here and there on this one.

 

[hakcenter]

Might want to have someone weld a drain fitting on your ic, lower than the bottom so it actually holds oil, then you can lift the car on one side and have the oil move to the drain.

 

[Kapok6]

I've thought about that, but I don't know that there is enough oil in my intercooler to flow and drain, especially since I have a filtered catch can the air has to go through first. It's more of a mist/residue, than a pool of oil.

I will probably pull the IC and baptize it with gasoline or mineral spirits.

 

[bling5tatus]

Good talk guys. Pretty funny you're saying vacuum pump isn't good for DD when they come on DD type cars from the factory. Makes perfect sense.