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handy with the steel
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a hose to the intake?
Do you mean the turbo intake or the intake manifold?

If you plumb a hose to the turbo intake, this method will "work" but you'll be ingesting oil vapors directly into your turbo which will then coat the all of your charge pipes and intercooler. No thank you. I'm curious how much vacuum is actually present at the turbo inlet to even take advantage of for this purpose (I honestly don't know).

If you mean intake manifold, then it just plain won't work for anything other than crankcase blow-by while the engine is operating under vacuum. As soon as you're in boost there had better be a check valve installed between the manifold and the catch can, or else it's going to be directly pressurizing the crank case.
 

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Actual member since 2001.
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If you are going to do it, then do it right. Welding a brand new set of valve covers isn't going to harm them. If you use the press in fittings you are creating a huge bottle neck. I had PHR weld my covers, blasted them, and had them powder coated. Then I took them apart after powder and cleaned the insides to ensure no debris got into my new engine. Put the baffles back together and you're set.

STeve
Would you happen to have a picture of your finished valve covers? Also how much did that run?
TIA
 

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I had mine powder-coated gloss black. They have 1/2" NPT holes that accept a 1/2" NPT to 10AN fitting. Since the cover metal is kind of thin, I had aluminium bungs welded into the inside so the fittings have some serious metal to bite into. This is all feeding into the Radium dual catch-can setup with vent-to-engine.
Musical instrument accessory Bicycle part Bicycle fork Automotive exterior Rim

Bumper Tool Wrench Ratchet Automotive exterior

Don't have any shots with the fittings in (yet). Head is going on the motor this weekend - wish me luck.

It's very tempting to swap the exhaust side can for the Radium AOS can ...
 

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I am switching from a catch can vented to atmosphere (Dual radium press-in fittings in the valve covers to the catch can) to an exhaust evac system. I am putting the check valves midway through the -10AN lines to the exhaust so they are not exposed to the heat of the exhaust.
 

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The Radium cans have 10AN openings, but use 6AN for the intake/pcv side and 8AN for the exhaust side. I upgraded the exhaust side to 10AN, and am using the Radium PCV valve for the intake side.
I saw that in the website. Why would they do that? Why not just offer 10AN all around? I’m leaning towards Radium VTE also. Although AOS appears to be the best way.
 

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Lagmeister
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So between this thread and the other recent thread about PCV, what’s the best for a fresh built motor, hoping on good ring seal and longetivity ? The radium VTA or radium VTE ? what’s wrong with VTE if the catch can is inline ? Isn’t it supposed to have a lot less “oily air” recirculating back into the turbo air inlet pipe ?
 

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AFK
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You want to explain how that is supposed to work in a forced induction application?
Factory PCV system is ideal





Its the OEM Pcv setup you want.

Clean Oil from crankcase drawn towards the turbo will protect the turbo. Like when you add oil to any other metal materials, it is a protective desirable coating. All Factory turbo cars use light oil crankcase gas to protect their turbos. Never catch the oil or stop the oil. It should not be a mist or liquid oil, it is merely oil vapors, oil as a gas state won't impact or harm the compressor wheel.
Otherwise you need to remove the air filter periodically and oil it manually. I still shoot mine with WD40 now and then.
That is, if you want 200,000 miles from a turbo you will. If not, then It won't matter I guess.


The reason OEM pcv seems to get a bad rap is because people fail to make the connection between crankcase pressure and gas density of the crankcase carrying oil quantity. If the crankcase pressure rises, the gas density of crankcase is higher, which allows more oil aspiration, liquid oil has a hard time returning to the oil pan and remains suspended in the gas flow of the PCV system frequently. That is how you get the large liquid oil droplets coming out of a crankcase and coating all the intercooler stuff, making the OEM pcv look like a terrible idea. In reality it was the owners fault for not measuring the crankcase pressure and improperly modifying the PCV system that causes this. For example if you place a very high flow air filter on the turbo, there will be no PCV pressure drop on the crankcase (look at picture #1). Or use no air filter is even worse. That means high gas density will blow out of the crankcase and bring alot of liquid oil with it, right into the turbo or wherever the crankcase is vented to at that point. To put it another way, the less pressure drop on the crankcase at WOT, the larger the lines/cans attached, the more oil will blow out. So merely adding a catch can will actually reduce PCV effectiveness and increase the quantity of oil blowing out of the engine...

There is nothing wrong with catch cans. I just don't see any need for them on a healthy engine. Control the crankcase pressure and let the light oil vapors protect the turbo. Nothing can reach past the turbo outlet if the OEM system is setup properly to sufficient crankcase pressure drop. Obviously there are exceptions, thrashing the engine, super high redlines, internal mods to the motor which disrupt baffles or change oil whipping/windage, large ring gaps on loose forged pistons, etc... You have to make a judgement call between using a vacuum pump and using the OEM pcv or using some other means of crankcase evacuation system (such as venturi, exhaust driven, or electric pump driven) but one way or the other you MUST ensure the crankcase pressure for ALL Engines no matter how mild to wild will remain lower than atmospheric pressure, even if just by 0.5" Hg, at all times, for various reasons, not just oil control.
 

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Lagmeister
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i appreciate all that info, I’m rereading it and trying to soak it in. The diagrams helped too. Can you draw onto this photo the best way for me to set it up ?

Vehicle Hood Motor vehicle Car Automotive design

the black box by the firewall was a distributon block that i connected things to as if they were the intake manifold. It worked okay but I am going to revisit this and delete that block and weld respective bungs on my plenum. I’m in the middle of redoing my setup to those twins and would like to setup the pcv system as ideal i can for a moderate power , often driven, street car.
 

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Lagmeister
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that’s extremely helpful, much thanks. Is there an ideal entry angle for the fitting on the turbo intake inlet ? I noticed on your examples above on the V8 and RB they’re both pointed away from the turbo.
 

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AFK
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that’s extremely helpful, much thanks. Is there an ideal entry angle for the fitting on the turbo intake inlet ? I noticed on your examples above on the V8 and RB they’re both pointed away from the turbo.

Make it convenient for your setup, make it look however you want. Hide it underneath is fine, point any direction. You aren't sticking the fitting INTO the air intake tube, The interface between the inner diameter of the intake tube and orifice is flat, where fluid flows towards the turbo, thus any energetic-kinetic based pressure drop will be similar and negligible no matter what the exterior tube angle is. There is no necking down region as in a venturii to induce a velocity increase along with pressure drop. In other words the PCV action supplied by air filter at WOT is pressure scalar based, not kinetic or potential energy based. The entire tube is pulled down into a vacuum and that exerts pressure drop on the crankcase and any tube attached no matter how it is attached.

For a healthy engine, the lower crankcase pressure = less blow-by = less PCV flow required.
Its a feedback loop, you drop the pressure and the blow-by will decrease, allowing pressure to drop a little more, and a little less blow-by, until a diminishing returns at the piston ring function with some reasonably low crankcase pressure, the result of which is very minimal crankcase flow into the turbo and reduced oil leaking with best piston ring function.

It works both ways, lack of pcv pressure drop = rising crankcase pressure = increased blowby = reduced piston ring function = increase crankcase pressure = reduced piston ring function = increased blow-by = more gas blowing out of the crankcase = more oil induction to the intake = more blow-by = more crankcase pressure = reduced piston ring function.... around and around it goes in a positive feedback loop where blowby and diminished ring function leads to people complaining about all the oil dumping out of their engines. The gas forces applied to piston rings cause oil infiltrate to the ring pack which further reduce piston ring function, rings can't spin freely gummed up with oil, rings can't change position properly, or swap sides too early during critical period of a stroke causing ring flutter and increased oil consumption.

Its a whole slew of issues if we don't properly drop the crankcase pressure at WOT of any engine. Otherwise I Wouldn't be making such a big deal out of it.... I really feel that it is the most important system on an engine. Priority #1 is crankcase pressure and PCV flow, together with air filter quality.
 

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Lagmeister
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@Kingtal0n

with all the talk about the oily intake tract vapors reducing octane/knock threshold basically you’re saying the amount allowed with the oem pcv system and healthy ring seal is fine. what’s wrong with my filters ? they’re brand new GReddy.
 

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...

Clean Oil from crankcase drawn towards the turbo will protect the turbo. Like when you add oil to any other metal materials, it is a protective desirable coating. All Factory turbo cars use light oil crankcase gas to protect their turbos. Never catch the oil or stop the oil. It should not be a mist or liquid oil, it is merely oil vapors, oil as a gas state won't impact or harm the compressor wheel.
Otherwise you need to remove the air filter periodically and oil it manually. I still shoot mine with WD40 now and then.
That is, if you want 200,000 miles from a turbo you will. If not, then It won't matter I guess.

...
I've never heard of this before and don't see how coating the compressor wheel with oil and adding oil mist to the intake charge is a good thing.
 

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AFK
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I've never heard of this before and don't see how coating the compressor wheel with oil and adding oil mist to the intake charge is a good thing.
Well the compressor wheel is made of metal and air attacks metal. So you want a light coat of oil to protect the wheel. It also helps trap debris, fine particulate from air, alight coat of oil that you can wipe out once in a while will increase longevity and facilitate high mileage. Also oil molecules help with the seal to the housing, they can take up some of the space between blade and housing. Just like with piston rings, squirt oil, more compression, better seal.

Theres really no metal object positioned anywhere in the world exposed to outside air that wouldn't prefer to be coated in oil at all times, in terms of atomic crystalline lattice and electron transport potential, as so many gas state molecules such as water and oxygen constantly colliding with metals is opportunities for oxidation/degradation/reactions

"If you care about some metal, oil it"

Also, every turbo car from every manufacturer is setup this way. So you HAVE heard of it, you just never had someone explain how and why the OEM do this to every turbo engine. I'm not showing anything new- its just stock! It is quite beneficial when pulled off properly, and to do that, it is necessary to measure crankcase pressure using 2-bar map sensor, log it to a graph and review. Then adjust as needed. If you fail this one thing it may not work properly and that is the big issue everybody has with the stock setup- stock means stock air filter, stock turbo. Once you change the air filter or turbo or manifold or cam or basically any 1 single part, the OEM exact config for PCV needs also be tweaked to provide correct pressure drop, and it would benefit the most near pressure drop of 1.5" to 2" Hg on wet sump turbo crankcase to maximize the piston ring benefits at WOT. If the system only goes say 0.33" Hg and it has a high compression with an excessive ring gap and 30psi boost it might be a little too much oil density because 0.33"Hg is very close to atmospheric. That is when the air filter needs to be adjusted to provide + 1" to 2" Hg to the crankcase to prevent oil from coming out. 1.5" Hg is usually fine, you can 1000rwhp. I setup every turbo car like OEM 1.5" Hg crankcase with great success, even on originally non-turbo engines with Natural aspiration intended baffle systems and low RPM work truck situations, it will 1000rwhp in a daily driver config with this simple ~3/8" hose attached from intake to crankcase, a light oil smear develops at the bent in the air filter on the opposite side of the tube, it can wipe out every 20k to 50k miles (I'm always excited to see what I've 'caught') hit the blade with WD40 while you are in there and wipe around a paper towel careful not to touch the blade. I never remove the compressor housing, ever never. I know it comes right off but I would damage it. I am very hard on parts. I test everything to the absolute extreme maximum and find every bug, any weak link. I would not risk saying something unless I Was sure about it. I waited 20 years to finally realize and admit the OEM have it right. Its just you can't copy their exact config if you change parts on the engine, and I think that is what trips everybody up, to most people its just a PCV valve leads from oil to intake and the possibility of oil gushing out of an engine into the intercooler without any real idea about how its supposed to work or why the factory made those connections in the first place. The engines do not come with a manual to explain why each system was implemented the way it is and all factory engines have a slightly different PCV pressure range for their operating conditions. Some such as chevrolet will run close to atmospheric pressure at idle and others like 92 nissan 2.0L will be much lower at idle thanks to restrictor orifice in the PCV system. The crankcase pressure is a setting, like tire pressure, like idle vacuum. You can tune idle vacuum around with timing and fuel and idle RPM, and similarly you can tune the crankcase pressure with ring tension, compression, ring pack design, crankcase evacuation systems, PCV is just another tunable engine feature all along. It is the highest level of engine tuning possible, its like the art form of engine longevity and high mileage attained through air filtration and PCV. I couldn't imagine not putting 12k miles/year on a turbo car, get it done and drive it forever, if know how (you know how now) get 200k from the borg warner turbo and 200k from the stock engine, at least! I'm approaching 50k on my first LS engine that I ever owned and the first new turbo I ever purchased and the oil looks pretty damn good after 3k miles and the wheel is looking pretty new as well. Now imagine if I had not used an air filter, it would be done. The wheel would be shredded, the intercooler would be full of embedded debris, the throttle body and intake sandblasted, the pistons and rings ruined, materials embedded to the block and circulated all throughout the engine orifices and internals, the block is trash it could never be rebuilt or reused. It would probably have suffered a catastrophic failure before 50k miles actually, due to the relative size of modern oil orifices especially considering how much more air a modified turbo engine flows in time than a typical engine. Now, what about if I had not connected my PCV properly? What if I had not put a 1-bar map sensor on the crankcase and taken note that it was sitting 4.43v with the engine off. Then I start the engine and read my multimeter, 4.38v. Slight vacuum but almost nothing. Then I drive around 30mph cruise I see 4.23v, nice thats probably around an inch of vacuum. Good job OEM chevrolet pcv valve and OEM supra TT pcv valve, I used both inline series on my engine because chevy can't handle boost- but anyways. Now I go full boost 20psi and the 1-bar map steadily drops from 4.34v to ~3.89v and I can't really pay super close attention to the multimeter (but I could video it if somebody wanted a demonstration I might still do it) because of the high speed and tire spin and let off.
Then stop the car, disconnect the crankcase vent tube and just leave it open the atmosphere just out of curiosity (to make sure the 1-bar map is working properly) and see again the same pressure at idle and cruise, because the pcv valve still flowing as before. Then go WOT and notice the voltage climb from 4.38v to over 4.6v, apparently the 1-bar map can read up to around a full psi of boost at atmospheric pressure (and even more boost at higher altitudes) so it could be used for measuring crankcase pressure as a alternative to the 2-bar sensor since you never really want the crankcase pressure higher than atmospheric pressure anyways.

If the engine was left to vent with 1-bar map monitoring at the crankcase showing voltage increase 4.6v+ all the time at sea level, the consequences would not be as severe as the air filter missing. But it would still be abnormal wear and tear. Oil consumption will increase gradually, the worse it gets the worst it gets kind of thing. So at first not too bad but over time worse and worse. This is caused by forces which cause ring flutter and early piston ring switching during different parts of some of the 4 strokes, because of high crankcase pressure which applies forces to the piston rings and tries to force them up when the piston is trying to move down. Consider what happens if a low tension piston ring is used without a vacuum pump- oil consumption would sky rocket! It would be all up inside the combustion chamber. So what is it about vacuum that is helping with the piston ring tension? What sort of forces are applied to a piston ring because of a crankcase vacuum? These questions leads to answers that explain why oil consumption may decrease when blow-by increases, as crazy as it sounds, depending how a ring is designed. Forces which move liquid oil from the crankcase and into the combustion chamber are different from the forces of combustion gas blowing by into the crankcase, they need to be treated separately. To move the liquid oil the piston ring can merely switch positions rapidly- that is called ring flutter and it may transfer a large quantity of oil to the ring above, all the way to the combustion chamber over time like a steady stream in due course. It seems that oil is forced into the rings when crankcase pressure is high even in the absence of ring flutter, due to early switching of ring position and the resulting transfer of crankcase contents increases. Oil of course gradually thickens, stagnates, carbon 'glue' sticky tar-like and hard diamond like, carbon (surrounded by hydrogens, 'saturated' hydrocarbon) can fit and stick wherever it feels like in the ring areas and oil is made mostly of carbon chains so its like trying to build a wood house with wood- it will build up any amount of carbon and any type deposits and this will influence ring function, sealing properties, the ring being able to switch when it is supposed to, the ring may get stuck and prevent from spinning (It needs to spin apparently) or even get stuck kinda sideways I bet. Theres always 'that one engine' where it happened. Carbon as a deposit may favor certain types of bond length/angles based on the conditions exposed repeatedly. Like intense pressure turns it to diamond. 'Light' pressure like combustion 1000psi tends to make it hard 'diamond like' around the surface of the piston. I'm sure the engineering behind modern pistons is focused on providing specific spots for carbon fragments to collect or 'hang out' while they cycle through the combustion chamber eventually coating the exhaust system, it is anticipated that certain parts will hold a carbon film on their surfaces and this effect is carefully negotiated to prevent carbon chunks from hindering the engine mechanically. Some fraction of blow-by also finds its way into the crankcase no matter how good the ring is and blowby gas is harmful to the engine so the PCV system is always supposed to pull those partially combusted hydrocarbon fragments 'carbon conglomerates' which consist of blow-by gas, pull them out of the crankcase as quickly as possible, while they are hot and rapidly moving with good velocity in the PCV tubes, use very short tubes and focus on removing that high velocity hot blow-by gas and whip it back into the intake (any intake) so the crankcase oil system stays fresh and like new. A lower crankcase pressure helps the ring stay free from oil deposits, protects the ring health and function, and improves the sealing tension of the rings which reduces blowby. It also allows the rings to stay in a sealing position longer at the ends of certain strokes and prevents ring oil transfer behaviors as ring flutter. And low pressure also helps keep the pressure off the oil seals, helping to hold oil inside the engine. Everything is being drawn into the crankcase (low pressure = vacuum), and a particular flow route pathway is engineered to constantly deal with blow by gas, pulling it out quickly. The air inside the crankcase is rapidly replaced with fresh filtered air and the temperature is maintained near the boiling point of water to keep driving water molecules away from oil and into the PCV system.
In non-turbo applications you can gain power by removing the WOT PCV because now the engine can breath more fresh air to the intake manifold instead of recirculated blow-by. Its 'fine' for frequently rebuilt engines, engines that will never see 40k+ miles used as strict racing vehicles in 'seasons'. In turbo applications the turbo provides all the kinetic energy you could want by converting waste exhaust to shaft power, so there is no excuse for us unless competing in some kind of level playing field where everybody has to use the same exact turbo. In that case you'd probably neglect the WOT pcv side and also use the smallest displacement engine possible to minimize friction. I'm just saying there are exceptions to everything and not trying to make this into 'the only way' its just the way for people that need 200k from their engines and use them like daily drivers especially. And alot of those people don't realize it yet, to be doomed before buying a single part. Can you imagine

In short, it is my opinion that venting would cause the following issues to a majority of turbo engines from any manufacturer:
1. Over the course of 30k to 80k miles, oil consumption would increase and oil would work its way into the ring pack
2. Oil leaks will develop at any/every oil seal, such as valve cover, front/rear main, oil pan
3. The engine will be more sensitive to fuel octane, will detonate easier because of oil invading the combustion chambers through the rings, some engines worse than others
4. High crankcase pressure at wot further works against oil in the turbo drain line, it is common to find the turbo seals have blown or been damaged and the turbo is smoking and burning oil

Remember that was with the OEM pcv valve attached still- all I did was vent the breather to atmosphere and put 80k on the engine.
The vent gradually kills the rings and forces oil out of the engine and may cause detonation eventually
I'm sure theres breather engine examples which are still going with high mileage, there is always that one engine. It might not be possible to find two, though. And you can throw a rock to hit OEM intact pcv examples with 200k since 2010. There is a significant difference
Tune the crankcase pressure its 2022 :D
 

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Well the compressor wheel is made of metal and air attacks metal. So you want a light coat of oil to protect the wheel. It also helps trap debris, fine particulate from air, alight coat of oil that you can wipe out once in a while will increase longevity and facilitate high mileage. Also oil molecules help with the seal to the housing, they can take up some of the space between blade and housing. Just like with piston rings, squirt oil, more compression, better seal.

Theres really no metal object positioned anywhere in the world exposed to outside air that wouldn't prefer to be coated in oil at all times, in terms of atomic crystalline lattice and electron transport potential, as so many gas state molecules such as water and oxygen constantly colliding with metals is opportunities for oxidation/degradation/reactions

"If you care about some metal, oil it"

Also, every turbo car from every manufacturer is setup this way. So you HAVE heard of it, you just never had someone explain how and why the OEM do this to every turbo engine.
Interesting take. I don't agree with the rationale here.

  • trapping debris: air filter, also the compressor is spinning at 100,000+RPM and the Gs at that speed will shed surface wetting in addition to the sheer airflow over the blade shedding lubricant
  • sealing: there's no physical contact of the compressor and housing and I cannot see how there would be any oil film creating a sealing effect under boost with high airflow and high G on the blade
  • atomic crystalline lattice and redox potential - I don't see any practical impact under these conditions and the service life of these parts
Of course I've heard of PCV systems spitting out oily air into the intake pre-turbo, I have never heard of this oil in the intake charge providing any benefits to the turbocharger's lifespan or efficiency and would need to see engineering data or the similar to back that up as it doesn't make sense to me.
 
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