On my first setup I remember running an NPT 90* fitting into the map sensor port on the back of the intake and setting the map to the side a few inches.

The current build offers a bit more space at the firewall with a 3/8" dropped set of engine mounts.

The map sensor goes in fine. Doesn't remove easily. But nor does it feel highly solid. The nature of that rubber grommet on I guess.

To those with experience: if I leave it as is am I inviting a leak, or should it be fine to run as is?

 

Bump.

 

I'm just a na guy but I put silicone around mine to play it safe. I didn't like how lose it felt.

 

You must pressure test forced induction applications and set crankcase pressure manually.

there are many leaks to discover. This allows you to test PCV valves, hoses, map sensors, etc...
GM Original pcv valves will generally leak boost into the crankcase. Because people do not pressure test, they don't know this. It is a secret performance tip to utilize supra Twin Turbo PCV valve instead of or in conjunction with GM PCV valve.
The result of using only GM PCV is this: The owner notice the engine leaking oil, blowing out oil. They complain about the oil issues, and many will buy a catch can, while ignoring crankcase pressure and allowing the PCV to continue fail completely, while the crankcase is under pressure, which leads to accumulation of carbon byproduct in engine oil, deposits in oil orifices, accelerated wear and eventual failure

Because the trend has been going on for so long, so many have copied and pasted without understanding. Nobody is measuring crankcase pressure here in V8 land, yet.
If you want to successfully run a forced induction application, you MUST pressure test the entire system, and you MUST measure and set the crankcase pressure properly, manually, just like fuel pressure, tire pressure, coolant pressure, boost pressure, oil pressure, etc... Every pressure must be controlled including crankcase pressure.

Fill the entire plumbing from compressor through to intake manifold with more than the boost pressure you intend to ever run.

If you need a video of how to do this, I made it

If you do not pressure test, big mistake. Escaping air molecules is lost power, losing boost, less boost.
In turbo apps it also leads to high IAT, high EGT, high EGP, engine failure & turbo failure.

Then, to measure and set crankcase pressure,

Together, pressure test, crankcase pressure setting point, Proper PCV system, the engine can stay clean, healthy, no oil leaking, no oil blowing out, no oil issues. It will maintain piston ring sealing, prevent oil accumulation in ring packs, prevent excessive blow-by due to early ring switching and ring flutter. This is the proper way to utilize forced induction. Do not use a catch can. Do not allow positive pressure inside crankcase at any time.

 

no doubt with higher boost you are going to get some blow by no matter how tight the engine seals and crank case pressure needs to be managed.

the catch cans with one way check valves that are also vented are often used. What setup should it be?? crank case pressure even with the best ring seal is inevitably a result of higher boost

what do you recommend in lieu of the catch can?

 

1.5" to 3" Hg controls blow-by under boost, prevents blowby from becoming excessive.
Engines make excessive blow-by for few reasons, if they are originally healthy
1. Positive pressure in crankcase
2. Accumulated carbon between and behind piston rings due to high crankcase pressure from #1
3. Ring tension lost due to high temperature (Over heated the ring pack) this happens if EGT rises too high just once


Example engine1 in video above
5.3L received with almost 200,000 miles, worn out, expect large blowby numbers under boost
18psi of boost 500-600rwhp, no blow-by issue with crankcase pressure set to 1.5" to 2" Hg as per video
I put 50,000 miles since 2017 on the engine, now close to 240,000 miles total , no issues. Maximum reliability.

Example engine2
2.5L RB25DET Skyline engine
Forged piston, large piston wall clearance. Large cold leakdown number.
32psi of boost, 600rwhp dynojet E85




Same crankcase evacuation, valve cover to compressor inlet. No catch can to interfere with kinetic energy and fluid momentum.
Low crankcase pressure protects piston ring function, prevents accumulation of carbon in the ring pack, prevents ring flutter and early ring switching.

The reason people think that forced induction causes lots of blowby is because they do not measure and set their crankcase pressure properly, then over time the issue gets worse and worse, blowby increases as ring function declines, baffles fill with oil, engine oil starts to spill over and oil seals begin to leak, and ring function declines especially without proper air filtration. The top of the ring carbon accumulation is dictated by air filtration, there are many particulate in air that contain carbon which becomes deposited to ring packs over time and can circulate into engine oil causing wear and failure. The Bottom set of rings accumulate carbon byproducts of combustion at a rate which will dictate by crankcase pressure, high crankcase pressure allows accumulation of partially combusted hydrocarbon and carbon conglomerates causing stuck rings, and interferes with gas pressure vector force behind ring lands which helps hold the ring to the cylinder wall. All together ring tension and piston to wall clearance along with running temperature (thermal expansion) relate to blowby character, and whether or not the ring is kept cleanly or not. To keep rings clean is quality air filtering, crankcase pressure setting 1.5" to 3" Hg at wot.

I've setup and tuned hundreds of forced induction vehicle. The method I show works every time if pulled off properly. Pressure test ensures pcv valve is working and air molecules are contained into plumbing. Crankcase pressure test is like a fuel pressure test, you measure and set it properly. Then, no matter what power, boost, ring gap, etc... the blowby is controlled by low crankcase pressure. No oil can be forced from the engine if the crankcase pressure is kept low enough.

 

but what about getting rid of the nasty contamination in the oil? I get it's a restriction but once I get the nasty oil separated I don't want to put it back

back to measuring and controlling back pressure. If we are saying catch cans need to go because of the flow restriction wouldn't a low restriction one be better than none?

no matter what water vapors get into the crankcase and oil. Even worse if you never get the oil up to temps. Hmmmmm............

So on my old drag cars with high compression, we used a vacuum pump to help evacuate the crankcase pressures according to rpms

they were not adjustable but did a great job of keeping pressure out of the crankcase and the cars picked up power despite the drag of the vacuum pump

crude but effective. so I get the measuring part, help me keep the oil clean too and better manage any crank case pressure that may be excessive

I don't think elimination of the catch can is a great idea, it has a purpose and as long as it's not too restrictive, I think it's worth it.

 

This doesn't make sense, it isn't chemistry you quote. Blow-by gas exits the cylinder through the rings, at THAT MOMENT it hasn't contaminated the oil yet. If you slow the oil down along with this blow-by gas and pressure rises NOW it is contaminating the engine oil in the lines, can, and crankcase volumes. The goal is to create a streamline -> a kinetic energy vector component for continuous evacuation, as opposed to a scalar pressure component of rising pressure due to excessive volume and enlarged lines. Imagine a line empties into a 5 gallon bucket, what happens to the streamlines as they enter the bucket? Suddenly the organization is lost, there are no more streamlines. Instead, the kinetic energy is dominated by temperature, like air molecules contained within a tire or balloon. Now they collide at random with each other and the entire volume of their container, instead of flowing in an organized streamline from one end of the 'tube' (5 gallon bucket is a very large tube) to the other.

Engineers designed the crankcase evacuation for wet sump to hold pressure low on one side of the crankcase, opposite from fresh air induction, which creates streamlines and kinetic energy velocity vector component for gas molecules exiting the cylinder. This way blow-by gas never gets a chance to interact with engine oil, so long as the pressure gradient and flow streamlines are maintained. The mistakes people make are many, but primarily, adding volume which increases pressure allowing disorganization, and not properly setting the low pressure end of the PCV system during idle/cruise/wot specific to the application by adjusting air filter pressure drop and PCV valve orifice flow pressure difference (differential pressure which drives the gradient)

 

I never said anything about a restriction to flow. I refer to the fact that additional volume of gas or friction will absorb/require additional kinetic energy, adding cans or lines will induce additional volume and/or friction and to move more gas volume requires more energy, where does that energy come from? When a piston draws air, the energy is supplied by the engine pumping. The engine IS a vacuum pump. So if you wish to effectively vacuum pump 1 liter or 2 liters or 3 liters etc... of air, the more air it will pump, the more work the engine has to do on the air volume. The energy supplied is finite. If we increase the crankcase volume, we need more energy to pump the extra gas volume, now the engine must either work harder, or the pressure difference (gradient P) will drop in magnitude, reducing effective PCV energy supply and causing myriad consequences such as reduced piston ring function. Remember crankcase pressure is a component of ring sealing, i.e. they make low tension piston rings for vacuum pump applications as an example. What this means to us is, there will be less effective crankcase evacuation, OR extra energy is supplied by the engine which takes away from fresh air induction to make power. Either way is a loss, an unnecessary loss.

 

no matter what you do water vapor enters the crankcase and contaminates the oil along with blow by gas and other oil contaminants That water will not do the lubricity any good. Take a look a the "puke tank" on a funny car for extreme example of blow by. After a pass the oil is so full of fuel that it's no good.

In a less extreme example, the same thing is happening to street engines with contamination from water vapor in the air from condensation and blow by hitting the oil all the time.

having a well designed catch can aids in getting those contaminants out of the oil is something engineers invest lots of time. with direct injection, getting rid of oil suspended in the intake air is also critical to keep the back of the valves clean as you don't have any fuel to wash those contaminants off the valve.

not having any help there just means you flow that back into the intake air with nothing to separate out those contaminants. Maybe I wasn't clear enough. You can suck that stuff back through the engine if you want, I'll chose to keep my oil clean as borne out by the oil analysis

have you tested the oil on cars that just "flow it all unrestricted" as you say back into the engine?? Why would you want to do that? The engineers that design all this aren't selling snake oil but rather trying to keep the contaminants out of the oil.

 

I think you are quite confused without any chemistry background. Your words make no sense. I am not picking on you. Please read carefully.
Blowby gas is a gas. It cannot be captured inside a catch can. The can will do nothing to help reduce or control contamination of blow-by gas.
There are no engines ever produced by any manufacturer which includes any kind of catching can. All oil/air separators from all manufacturers rapidly return hot engine oil to the oil pan before it can interact with blow-by gas or collect in any significant volume.
Matter we are familiar with exists as 3 states: gas, liquid, solid. Blow-by gas is a gas. 1 mole of any gas molecules take up 22.4L of volume at STP (standard temp and pressure) in classical physics.

The best way to keep blow-by gas out of engine oil, is to remove the blow-by gas immediately using PCV, and pull it out before it can interact with engine oil. The longer you wait to remove the gas, the longer the lines, the larger the volume, etc... the more contamination will occur as blow-by gas diffuses into engine oil over time at some rate. There is no way to remove contamination from engine oil without changing the engine oil. If the oil is so contaminated with blow-by gas that it has been saturated with blow-by gas and now the blow-by is diffusing rapidly out of the engine oil, then it means the oil is already fully saturated with blow-by gas and you have failed, the pcv system is broken.

If you stop the engine oil somewhere such as a can, now it can interact with an contaminate the engine oil. If the crankcase pressure rises, gas density increases, and this will suspend more oil droplets (liquid droplets much larger than gas molecules) and the PCV system will take up increased engine oil with blow-by gas because of high crankcase pressure. High gas density also forms larger oil droplets suspension as increased collisions with reduced mean free path between suspended particles at high density.
Therefore, high crankcase pressure causes more oil to blow from the engine and increased pressure on oil seals, more oil leaks, and reduced piston ring function, which causes increased blow-by and more oil contamination.


This doesn't make sense to me. What engineers? No engineer ever designed a catching can for any OEM engine. Engineers outside the OEM design products to sell which may be harmful to the engine. You can still buy cigarettes and smoke them if you want. It isn't illegal to sell harmful and damaging products, just because they are 'designed by engineers' doesn't mean anything. I am engineer, I can design a catch can, perfectly to catch oil and make it so that it will trap a whole bunch of oil, way more than you would normally see, by simply inducing friction to cause high crankcase pressure and forming large oil droplets with which to separate in my engineer'd can. Then people will think it really works well, because they see a bunch of oil collected, and hype the product. When in fact is causing long term health issues, like smoking, for the engine which will develop gradually and by the time they are noticable the owner won't have any idea why or how it happened, and no way to connect the issue with the can they installed. And the company is interested in selling the product, its easy to sell a $40 or $100 product to lots of people who will face consequences 5 to 20 years down the road without being able to connect the symptoms to the product they purchased 5 or 20 years ago that seems to be working fine.

I think a real problem is engineers frequently lack chemistry background. Mechanical/electrical/control engineers curriculum includes very little chemistry. They have no idea what they are doing to the engine by designing a 'helpful oil catching can'. And there is very little if any data to back up any claims for any catching can system. In science, to publish a paper or document, you must have data, quantitative and qualitative data, which can make some claim. And even then, the way experiments are performed and under what conditions is always consideration and suspect, it takes more than one group of scientists testing a particular claim and making their own data to make convincing argument. I am a scientist, I read the papers published regarding the pcv system before I came onto a forum to discuss these issues. I built many vehicles for my own testing purposes as well as inspected a thousand imported engines with and without pcv systems to gather data. Over the last couple decades I've tuned hundreds of engines from all types of vehicles, every type of stand-alone computer, and all size of engine and application. These data & builds & education lead me to understand what is really happening inside the engine, how to visualize the blow-by gas and efforts of piston rings and so forth. The methods I propose (measure & pressure test) have never let me down, it is possible to keep an engine very clean inside if you follow carefully what I say.

 

I agree the blow by gas contamination that goes in the oil stays in the oil

what about the water??? OEMs just run hot and try to get the water out through evaporation.

water in the oil is no bueno. So the concept is more about the catch can separating the water out of the oil which also does indeed carry some contaminants.

I don't think the engineers that design after market products are all dumb as you say. No doubt you do works for you. I'm not quite convinced yet about that just because OEMs don't do catch cans, that they don't work

They have budget and emissions targets they have to meet. And they very much like to sell engines.

Maybe some vendors can enlighten here. Thanks for the info. I'll endeavor to eschew obfuscation going forward. Most folks understand my words just fine.

 

Water is in the atmosphere. When you shut off the engine water can begin to fill the crankcase via vent hose route.
Water is a primary byproduct of combustion, as a gas state. Water fills the crankcase during operation.
There is nothing you can do about water other than heating the engine oil to drive out the water periodically.
As water leaves the crankcase, it begins to cool and mix with engine oil in lines. This is why using a very short hose is important.
If you increased the length of hoses, and add volume, water has longer time to cool and mix with engine oil. This is the main reason not to use long lines or catching cans.
The catch can will not maintain the hot high temperature of engine oil properly. Any external air/oil separator added by OEM manufacturers is placed near exhaust to maintain high temperature to keep oil from mixing with water.


This is, again, nonsense. Water is most of the blow-by gas. The entire crankcase is full of water during normal operation.
Water as a gas cannot stop in the catch can, so it must return to the combustion chamber rapidly. This is how OEM pcv works, quickly removes gaseous water.
If you added a can, you are helping causing oil to mix with water. This is not good. Adding volume and additional places for water to collect is bad. Water rapidly cooling down can turn to liquid and collect in hoses and the can, mixing with engine oil.
Do not increase the length of lines or add volume to the pcv system so water can remain hot and high velocity gas. As a gas state, it will not collect inside any catch can.

There isn't really anybody higher to consult with on this issue. There are sales people, and then there are doctors and scientists. You want to discuss these issues with sales people, or a doctor/scientist?

 

I talk to the engineers and while I agree with much of what you say, I don't think these engineers are selling snake oil either

Talking to the Dr won't help, and the scientists that get stuck in the theoretical aren't much better either.

I hang out with the engineers and the hard core racers, and see what they do. They go to great lengths to keep the oil at the right temps and as free of contaminants as possible

the pcv does a great job for what it is, but it's not the only way as you present. You must be a scientist :>

 

I am engineer and I have nothing to sell. I only supporting evidence for maintaining the OEM pcv system specifications, and how to do that.
Most people do not realize that by modifying the power of an engine, or air filter, they are also modifying the OEM pcv system in some ways.
I feel the power and air filtration is where this entire issue stems from, nobody understands the connection there, no even engineers.
This is why I've done research on PCV for 20 years. I am not a theoretical scientist, I am a practice what I preach approach science and I collect data from my own projects and inspect engines from other countries over the course of 20 years to gather the evidence necessary to fully understand the PCV system.

With respect to chemistry,
I'm not saying an engineer can't develop a milk jug which can catch oil. An ebay $5 can will do it.
I am saying they may not have background in chemistry necessary to understand or correlate the effects that attaching a milk jug to catch oil is going to have on the gas behavior inside the crankcase. I am seeing evidence to support this claim as people fail to appreciate the difference between a pressure scalar (open venting) and a kinetic energy streamline of fluid (positive crankcase evacuation). There is alot of copy and paste happening, and nobody is doing the math or measuring.



PCV is using a vacuum pump and/or dry sump pump and/or other means of suction such as venturi in exhaust.
Engines are a vacuum pump and OEM pcv relies on the engine as a vacuum pump to drive PCV.
These are the only way to do PCV. PCV literally means Positive crankcase ventilation, as opposed to venting via crankcase pressure scalar. The word or term PCV literally implies a suction and pressure differential gradient with a low end less than atmospheric pressure whereby resulting crankcase pressure as measured is reduced below atmospheric pressure.
So yes, This is the only way to do PCV is to actually have a PCV suction applied to the crankcase, otherwise the word PCV doesn't define PCV by definition.

I think what you mean is, OEM engine pump driven PCV is not the only way to do PCV, which is true since you can use a vacuum pump or dry sump system or exhaust venturi. Those are all ways to achieve PCV on the crankcase. Vacuum pump is the superior however they are maintenance hogs and additional complexity and the benefits are not realized fully in wet sump applications and engines with high tension piston rings.

Honestly this issue is huge, it spans a book. I wrote a book already online over the years. I have videos coming up to fully explain the chemistry behind PCV, using right from the book. For example here is chemistry book partial pressure, vapor pressure, showing the issue with pressure and dissolved gases I spoke of earlier



Take note of 'dynamic equilibrium' in this example pages. Notice the behavior of the gas as it can leave solution or enter solution based on pressure.
This is in essence one major failing of engineering outside of OEM for devices such as catch cans. You get a degree in mechanical engineering and design some fluid system without any conceptualization of the behavior for gas molecules in separate phases, it goes unnoticed. The engineer can calculate flow rate, velocity, mass flow, rheynolds, pressure drop, etc... but does not account for gas partitioning between phases or gas entering the liquid over time because the mechanical engineer curriculum does not cover these issues. It takes several engineers if not hundreds coming together from various backgrounds to design a purposeful and complete system such as PCV. I think Chevrolet spent a billion dollars and hundreds of engineers coming together to design the best engine possible, then outside 1 engineer incapable of fully appreciating the system already implemented by a billion dollars and hundreds of other engineers makes some change and has no way to know the consequences in such a subtle system.

 

alot of the racers use a vacuum pump to ensure PCV I did notice that the lines were short and direct on my BB chevy
the reduced ring flutter at high rpms was worth a bunch of power
sorry if I came off as snotty. Weather here is awesome and I'm going to the domestic vs import drags
fastest turbo imports in the country, and many of the Peurto Rico Import pro stockers will be there\
very entertaining as we see 5.80s at 240 in the quarter mile from a JZ 6 banger turbo which is durned impressive

 

Is this the one in Maryland? I know a few local guys who went down with some 7 second civics and a few 2JZ builds. One of the civics runs on the streets up here and is awd converted. The other one is more serious.

 

Yes. Maryland international raceway in budds creek. Great track, weather looks great on Saturday. Yamobethere

 

I was invited down but I've got my sister and nieces in town from up north for the weekend and this will be the Christmas exchange since they've got travel plans at the holiday.

Maybe next year. I hear that event is literally THE one to hit. Also, I lived in pgc out of Mitchellville when assigned in 2006. A lot of good times down there!