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Discussion Starter · #1 · (Edited)
Here is a new post on Cruzetalk.com related to an oil Catch Can on the 1.4T. [removed off-topic sentence]. I am making no claims about the benefits at this point, so my goal is to figure this out with real world personal experience using my time and capital.


I am designing custom machined aluminum adapters for the turbo side of the PCV system. This will create an extremely robust interface without dealing with the corrugated plastic factory hose, in addition to a more professional clean installation.

This attaches to the turbo and includes a built in check valve:



Assuming this post doesn't get moderated, I will keep everyone up to date with the design, fabrication, installation of this system.
 

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The following technical points are made to challenge your own knowledge (which you should be welcoming gladly in the interest of technical progress), as well as provide a knowledge base for other readers to reference when considering similar efforts.

The use of catch cans has been widely debunked as unnecessary on this forum, and I challenged your notion that it was beneficial or necessary. I've compiled a list of technical points and follow-up questions I feel appropriate given the subject line of this thread and the inevitable google hits it will attract:

1. No statistically significant failures or have been attributed to this engine with respect to either sensors, seals, or other components as a direct result of oil consumption. These engine components are oil and fuel-safe and to date have not been reported as damaged, compromised, or otherwise degraded as a result of the oil found in the intake path. Do you disagree with these statements? If no, what exact problem are you trying to solve?
2. Oil found in the intake manifold, throttle body, and intake tract downstream of the turbo has not been proven to be exclusively or even mostly from the PCV outlet at the turbo inlet, and may also be caused by oil seeping through the turbo seals. Have you identified where the oil is coming from?
3. The use of a cheap, low-volatility synthetic oil such as Pennzoil Platinum 5W-30, with a 9% NOACK volatility, significantly reduces oil consumption by means of vaporization to negligible and almost visually immeasurable levels. As a result, oil consumption with an otherwise properly functioning PCV system is not a concern. Do you agree with these statements?
4. Catch cans are well-known to accumulate significant levels of condensation and require regular maintenance. That condensation freezes in the winter and, left unattended, can block the PCV port entirely. Do you agree with this statement?

The above points can be summarized as follows: what documented problem (failure/issue) are you trying to solve or prevent with the use of a catch can? Another way to re-word this question is, what failures/issues will someone experience by not installing a catch can, and where are those failures/issues documented? Note: we have members with vehicles that have run for over 300,000 miles that are not reporting any failures directly correlated with or caused by oil being in the intake tract.
 

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Discussion Starter · #3 ·
If we want to talk benefits, I will need to report back with real world empirical evidence collected by me personally. Like I said in the conversation that was deleted, I found notable trace oil amounts in two low mileage Intake Tracts as well as anecdotal evidence in a Sonic forum post that I had linked previously that showed contamination being collected in a can.

Whatever the results, they would be limited to my personal drive cycles, region/climate, vehicle modifications, boost level, oil type, catch can efficiency and other factors that may prove or disprove the benefits of a catch can on an overboosted Cruze 1.4T.

If I am 200%, 100%, 80%, 50%, 20%, 0% WRONG, it doesn't matter because you and I had a technical discussion that 3,000 Cruze owners will read and use to formulate their own opinions. That is pretty awesome!
 

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If we want to talk benefits, I will need to report back with real world empirical evidence collected by me personally. Like I said in the conversation that was deleted, I found notable trace oil amounts in two low mileage Intake Tracts as well as anecdotal evidence in a Sonic forum post that I had linked previously that showed contamination being collected in a can.

Whatever the results, they would be limited to my personal drive cycles, region/climate, vehicle modifications, boost level, oil type, catch can efficiency and other factors that may prove or disprove the benefits of a catch can on an overboosted Cruze 1.4T.

If I am 200%, 100%, 80%, 50%, 20%, 0% WRONG, it doesn't matter because you and I had a technical discussion that 3,000 Cruze owners will read and use to formulate their own opinions. That is pretty awesome!
I'm glad you don't mind the continuation of that technical discussion. It is indeed awesome. I think we have summarized the previous exchange adequately with this thread. Feel free to provide any missing information if you disagree.

As a bit of background, I'm on about 70 other Facebook automotive groups where these discussions occur on a regular basis, so this is not the first time I'm having this discussion and I'm certainly not attacking you for some reason unknown to you. You just happened to be the guy who seemed most able to engage on a technical level at this time.

I found noticeable trace oil amounts in my intake tracts as well. However, one thing I'd like to point out is that I had no way of measuring how much oil actually passed through there per mile or if that oil had been there for a while. This is why I made reference to the level on the dipstick. I filled my oil to just barely above the top of the hash mark on the dipstick when it went in. 15,622 miles on the same oil change later, it was at the top of the hash marks on the dipstick. The hash marks I believe represent one full quart from top to bottom, so we are looking at oil consumption over 15,622 miles of less than 1/8 of a quart. That speaks volumes to the effectiveness of the stock PCV system, not just the quality of the lubricant.

You will indeed catch contamination in a can, but bear in mind, this is mostly condensation, some fuel, some combustion byproducts (both liquid and solid), and a tiny bit of oil. If you'd like to put this theory to the test once you do install this catch can, gather a substantial amount of condensate from the can and collect it in a jar until you've accumulated half a quart. Then, find an old pan you don't mind ruining and boil the mixture until all you're left with is an oily residue. Measure that residue and you will find the totality of combustion byproducts and engine oil.

My objective as a CruzeTalk Gearhead is to ensure that others reading conversations such as this are well-informed to the benefits and drawbacks of modifications they perform to their vehicles, and the reason for my intensity in this particular discussion is the sheer amount of misinformation being circulated regarding these devices and the number of people installing them in an attempt to band-aid problems they should be addressing the root cause of.

All that being said, even if you are 100% wrong, the fitting you're developing will still prove to be useful as the corrugated hose does have a tendency to crack, and Cruze owners will want a solution that lasts longer than the last one.
 

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I can appreciate making improvements to a system if there is a problem and the solution provides improvement. But unless you are having a problem, is it possible in an effort to make an improvement that you may unintentionally create a new problem? I am not an expert on this subject, but sometimes in my view in real simple terms, "if it aint broke, don't fix it"
 
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My understanding is that unlike NA cars engines that have been converted to be turbo, the Cruze has a system built into the valve cover. In effect, it already has a self-contained, self-draining catch can. Anything external would be secondary.
 
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Discussion Starter · #7 ·
I found notable trace amounts of oil in two low mileage Intake Tracts as well as anecdotal evidence in a Sonic forum post on catch cans. I am also running an aggressive tune and about to get more aggressive when I get a meth injection kit. I completely get it can be an isolated problem, I get it can be something causing excessive oil entrainment through the PCV system. If I do have something defective in my system and I happen to catch oil, then we can fix the problems and see if it continues to catch oil to prove the "fix" solved the excessive oil problem. If the catch can does not catch oil, then I promise to post pictures of an empty catch can and we will all have another data point and another post to share with new folks asking about catch cans.

Some images from that Sonic post:




 

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Discussion Starter · #8 ·
My understanding is that unlike NA cars engines that have been converted to be turbo, the Cruze has a system built into the valve cover. In effect, it already has a self-contained, self-draining catch can. Anything external would be secondary.
My Cruze is slightly modified and I am near the knock limit with 19-21 psi of boost. I am under the impression there is a correlation between blowby and boost pressure, and looks like on N/A engines a rule of thumb I came across showed a relationship between Blowby Flow Rate vs. Horsepower.

I have just received some low range 0-5v pressure transducers to hook up to HPT. I can add one of these transducers to the valve cover, Xtreme has found a good spot when he did the bypass filter. We would be able to plot Crankcase Pressure vs. Boost Pressure and see what it looks like. Maybe the crankcase pressure is the same regardless of boost level, but it is a data point I personally want to see. With the PCV system looking like it has large cross-sectional areas, I wouldn't expect much difference if the PCV system can flow additional blowby without becoming a restriction (where the restriction is what increases crankcase pressure). If we do find higher flow rates from exceeding Factory boost levels, will the higher flow rates reduce the efficiency of the Factory Baffles in the valve cover?
 

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Is worth noting that the 15,622 mile run I had included testing of Trifecta tunes, and a ton of WOT dataloging of BNR tunes as well as being tuned the whole time at 21.5psi max. Just something to consider.

That's a lot of oil in that pcv outlet. Mine never looked wet with oil, just a dirty skid mark.

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I've owned two cars in the past where I ran forced induction setups that required VTA PCV/OCC systems due to higher boost pressure. And both setups were plagued with a frozen PCV valve, at some point, due to cold weather and condensation. Not fun!! At first you think the turbo seals are cooked since there are minimal signs of power loss, but when you pull the oil dipstick and air pressure is flowing out; you've realized that you're about to tear apart much of the top side of the engine just to check a $20 plastic valve. It's nice to see all the gunk get isolated from the incoming metered air...But when you're elbow deep into cleaning all the oil, that got pushed past the turbo seals, off the inside passages of the Intake, Throttle Body, IC, and IM; you'll ask yourself: "was the OCC setup really worth it?"
 

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I checked my oil level today after 7,000 miles. Note that I work from home full time and that the driving was almost entirely short trip, local, and spirited, and included towing my boat during the fall and other 5x8 enclosed and open trailers throughout the year. I'm BNR tuned and have a ported intake and rev to redline constantly. I haven't topped off the oil at all. For consistency, I always check the oil level when the engine is hot.



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Discussion Starter · #12 ·
I checked my oil level today after 7,000 miles. Note that I work from home full time and that the driving was almost entirely short trip, local, and spirited, and included towing my boat during the fall and other 5x8 enclosed and open trailers throughout the year. I'm BNR tuned and have a ported intake and rev to redline constantly. I haven't topped off the oil at all. For consistency, I always check the oil level when the engine is hot.



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That is a unique drive cycle. Mine is quite different. I commute 80 miles per day total, 5x per week. There is about a 22 mile area of freeway that is open with no traffic every morning, so cruise control for 22 miles. During this 22 miles, I am pretty much under boost 100% of the time. Here is a video to evidence this: https://youtu.be/0KpTrFYWbxc

That is a consistent 16-18 minutes of non-stop boost one-way everyday, times this by two because on the way home same story.

The first half of my commute (last half going home) is stop/go either heavy traffic or I am cutting through Detroit (Davidson/Mound). When I cut the city (often), I use lots of boost flowing with traffic and I leave home just in-time, so let's say I am aggressive on the pedal.
 

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That is a unique drive cycle. Mine is quite different. I commute 80 miles per day total, 5x per week. There is about a 22 mile area of freeway that is open with no traffic every morning, so cruise control for 22 miles. During this 22 miles, I am pretty much under boost 100% of the time. Here is a video to evidence this: https://youtu.be/0KpTrFYWbxc

That is a consistent 16-18 minutes of non-stop boost one-way everyday, times this by two because on the way home same story.

The first half of my commute (last half going home) is stop/go either heavy traffic or I am cutting through Detroit (Davidson/Mound). When I cut the city (often), I use lots of boost flowing with traffic and I leave home just in-time, so let's say I am aggressive on the pedal.
Reminds me a little of towing. I was pulling 5-6psi of boost for an hour straight on the highway with a loaded 5x8 trailer, which was also part of that oil change. Of that 7,000 miles, a solid 500 of them were hauling uhaul trailers between 900 and 1500 pounds. Another 500 miles was towing my 14' boat which weighs about 800lbs.
 

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Discussion Starter · #16 ·
0-50 SCFH Air Flow Meter purchased $7+ship. We will be able to get some air flow measurements in the Turbo side circuit for reference in addition to crankcase pressure when I get it instrumented. With the meter being transparent we can see the gases, now if I could only afford a spectrometer we can analyze the elements present in the gases. /s on the latter.
 

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Discussion Starter · #17 · (Edited)
New proof-of-concept, I radically changed the system and put the check valve at the intake manifold fitting to simplify the design and eliminate a spring and spring cup (point of fail, small parts to fly into the turbo compressor). Gravity will be the spring to hold the ball on the seat. The cracking pressure will be well under 1 psi. I am going to try to 3D print / machine these next week and see what happens during a short day test. I would make the actual fittings out of aluminum.



 

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So i just put a 2nd 3/4 pcv track in on the valve cover, preliminary results show massive drop in crank pressure. Was going to messure it but i got a 0-150 psi sensor so really low resolution around the 1-10 psi range. This mod was done last night, so im still collecting data
 

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Discussion Starter · #20 ·
Been bogged down, sorry the project is still in progress it will happen. Had issues printing ABS, so been upgrading the printer to handle it more reliably among other unrelated projects ongoing in my labs.

I just transferred to a new job position last week and was in a MY19 4cyl turbo dyno cell and asked a tech lead about the dyno setup (they are running two OCCs for each PCV exit out of the valve cover). They are not testing the PCV systems or emissions stuff, this is durability beat the crap out of components tests. The cans are large clear containers to visualize the PCV gases. A key question I asked was, "aren't there any baffles in the valve cover". The answer is yes but they're only good at certain load points (pcv flows, pressures), so if they are running an engine in a certain spot the valve cover baffles don't work very well so they use OCCs. He said it is kind of standardized dyno setup and a lot depends on what the engine is doing. He also mentioned the cans pick up a lot of fuel when the engine runs WOT rich which is expect and just thinking about it, I guess it could cause a rich condition if unmetered fuel is reintroduced to the combustion chamber. Another cool characteristic is that he has correlated PCV orifice size to Torque output including venting to atmosphere, the change is under 10 Nm, but that is significant for fuel economy.

This is a data point and something to consider, I translated this into the potential truth that the Cruze valve cover may not always be 100% efficient.
 
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