Thanks for the input 92rsz. My issue was that I was getting alot more oil in the can than I thought should be in there, and rightfully so. However, I have found out that I had my lines routed wrong. Corrected that and now just need to get some driving in to see exactly what I have going on.Originally Posted by 92rsz
Should make a noticeable difference. I never get more than a few ounces out of mine even after driving it hard with alot of engine braking
Around there. Less gets caught in the colder months. Oil temps aren't as high.
So what you're saying is that, given the Riemann sum of the Prandtl-Glauert effect and normalizing for the yield of sugar beets in Sierra Leone measured as bushels per hectare, we in fact need not one but TWO catch cans?
Yes.
For what it is worth, I actually did read this post and others you have made, and some have helped me better understand pcv systems. I just don't agree with all of your absolutist views. Then again, maybe everyone here is just a "weekend warrior" that only deals with worn out trash engines, engines that were perfectly designed but badly abused by the customer. Enough said, now lets get back to helping the OP.
This would probably only catch oil at idle/low load (vacuum) conditions, I think you would have negligible flow through the valley connection at heavy load, through the 2.5mm orifice. But I think you set it up this way just recently?, so maybe run it for some time and see what it does. You could still check crankcase pressure with a vacuum gauge at idle in the stall, to be sure at least it is pulling a vac on the system. The Wegner valve is not going to be a fix for anything unless you find that the valley plate fixed orifice is not giving you an appropriate flow rate at idle/light load, such as may be the case if you have a bigger than stock cam, etc. Measure first. If you did find that an actual pcv valve was needed, the valley plate would have to come off so that you could pull out the hose barb and drill out the orifice. Then, the flow rate would have to be controlled by the new pcv valve.
Last edited by NotSure; 12-15-2023 at 08:04 AM. Reason: additions
OK, so my customer installed a vacuum gauge and tested his Elite Engineering Venturi system. Again this one has their most updated valve.
Granted he was only able to free rev, so not the best test but what he found was this. At idle it's pulling just over 1 inch of vacuum on the crankcase at the valve cover (thought this was a little low but maybe not?) and then with a 5000 rpm "quick" free rev and "quick" hold it's pulling 8 inches with the gauge installed in line to the venturi itself this time. Again not a true wot with engine load applied. Thoughts? I haven't personally tested any to even have something to compare it to.
I really like how the fuel tuning is going with this kit. Honestly reminds me of an OE system, especially considering this is a procharged Ls3. Granted I have already dialed in a lot of the temperature and base fuel timing controllers, but either way I'm happy with what I've been seeing.
Last edited by GHuggins; 12-15-2023 at 10:36 AM. Reason: corrections
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Well looks like those engineers are not so dumb after all. They put a PCV return venturi barb on the factory LS3 intake manifold. The pic below shows OEM on left and modified "rod mod" manifold on right. To be honest the, the barb venturi is a pretty great hack for assisting to prevent PCV reversion during WOT scenarios.
factory ls3 pcv barb.jpg
A standard approach will give you standard results.
My Tuning Software:
VVE Assistant [update for v1.5]
MAF Assistant
EOIT Assistant
Interesting. I've never noticed that in one before.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
I think you want around 2-4 kpa on the crankcase, which looks like your customer had at idle, but the measurement taken right at the venturi would not be accurate for the whole volume of the crankcase, and luckily so as 8” would probably suck in the crank seal. Maybe time to use the old “gauge taped to the windshield “ trick and go for a drive.
Which kit was this? Did they do anything with VVE at all?
He said he would try to figure out a way to test while driving. Im curious myself to find out how much vacuum is applied with WOT. The 8inches was measured at the venturi itself so it should be less by the valve cover. It's the same updated kit as yours only he had some lengthy conversations with elite about it. I think that's why he got the updated valve. His be and maf are both staying really consistent now. Way better than the previous setup from procharger. Im impressed with it so far just in regards to that.
Actually Im saying that if you have oil gushing or flooding out of the engine at rest, like basically idle is as if the engine is off. Then its like you have oil flowing out of the engine while it is sitting off in the driveway. You need to think of how that is happening because it isn't normal. There are only two possibilities. One is, The volume is static but temperature is changing. Even at 1% blow-by 1% of 1 gallon is around 37.85mL of liquid. 10 gallons of gasoline therefore at 1% blow-by is almost half a liter of water. For 20 miles per gallons that puts you catching 0.5L Of H2O for every 200 miles. You go 1,000 miles with 1% blow-by now you have 2.5 Liters of water. 2% blow-by and double that. Whereas you are only catching a tiny insignificant fraction of that liquid, nobody is catching anywhere near 10% of the produced water. So why the fraction? And why does it matter? As the gas cooling it condense while the engine is off leading to liquid droplets forming on the surface area exposed and producing a gradual vacuum like a hot water bottle exposed to the cold it will suck in air. More volume = more surface area in this case so = more droplets. Your water is likely coming from engine off situations not from driving while the gas is hot and vaporized in the hot engine oil. Then, the liquid water partial pressure evaporating as the engine warms is killing oil viscosity in the vicinity of the outlet port on the valve cover allowing oil and water mixture to flow more easily out of the engine. Like a steam bath loosens the carbon up for cleaning on a hot stainless stove in the presence of a vacuum from density changes as gas cools. The other possibility is there is a crankcase pressure at wide open throttle which is pushing oil into the baffle system (which it should not be doing) and this is pushing oil gradually into the intake manifold. I covered this already far earlier in the thread. But these are the only two possibilities. There is no 3. The OEM PCV system sucks. Trust me it aint that my hose is dry and so is the hose of all the engines I've measured and setup properly from that point onwards. Of course every 30k miles or whatever I still clean the tubes or replace the $2 hose sometimes just for whatever.
When I see those cans there i Just SMH. You have added a little percolator to the side of the engine and facilitated the solubility of partially reacted hydrocarbons in the presence of water. The OEM Manufacturer has acknowledged this and warns people it could lead to lost oil and low oil pressure on the corvette.
https://www.corvetteforum.com/forums...post1593776123
Consider why they are worried about oil being removed from the lube system when using a catch can. Why is the oil being removed. What is it about adding a catch can that is removing oil. I mean, imagine we don't add a catch can right, the whole point of a catch can was to keep the engine from ingesting oil, which removes the oil. So why doesn't the OEM configuration remove oil 'due to ingestion' but adding a catch can does. Like, why would anybody install a can in the pathway of oil which was about to return to the oil pan in the first place? Is it... maybe... just maybe... that you can buy anything including cigarettes and drugs even if they aren't good for you or needed by your body? Vehicle.The Corvette's dry sump tank looks relatively simple on the outside but the internals are really quite complex. The top third of the tank contains a PCV air/oil separation system. On the Corvette, PCV lines route from the valve covers to the air/oil separator on top of our dry sump tank. Oil from PCV air is separated and returned to the lube system through the oil tank. "Catch-can" systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system.
I appreciate your test. The published target for random samples is here
For a stock engine not a performance engine. For performance we desire a bit more. OEM manufacturers of performance engines include restrictors like these, here is a skyline restrictor
The restrictor allows us to target any idle/cruise crankcase pressure. We set the flow of the pcv system at the intake suction orifice (or pcv valve(s)) and then set the pressure by using a restrictor if needed.
The low pressure does many things, for example it helps remove blow-by gas from engine oil by improving partial pressure of dissolved gas and also keeps combustion gas out of engine oil. Low pressure improves piston ring function which will reduce blow-by as well. Low pressure also keeps oil out of engine seals including piston rings, which prevents piston rings from occluding with oil where light hydrocarbon chains leaving over time leads to hard diamind-like carbon deposits and sticky tar-like deposits forming that stick piston oil control rings which ruins the cylinder wall and engine is toast and smoking needs a rebuild. So the low pressure is a critical feature of the PCV system and it does more but I think I have said enough there. And since its an idle/cruise condition the engine is barely producing any blow-by and has basically infinite manifold suction to create this pressure gradient it is no problem for any engine even the worst vacuum super highly modified engines can still pull the crankcase gas out effectively. The rules or experience part of this is that for wet sump applications a high vacuum can have many drawbacks (ruined oil seals, ruined wrist pins, ruined oil pumps, depends on the engine pump and oil squirts if applicable design) so it should be limited to around 1 to 5" Hg with the performance target being near 1.5 to 3"Hg of crankcase pressure for idle/cruise, slightly higher than random samples from OEM engines I've taken which are often in the 1" or 0.5"Hg ranges (We use inches of water not mercury but im keeping it simple). This why adding a vacuum pump to a wet sump engine is a kind of waste without extensive oil related mods.
Now, none of that really matters in terms of blow-by or catch cans because its for engine rest conditions. Engine rest is no hurricane and there is very little combative disruptive turbulence in the crankcase from a high rpm condition and lots of blow-by to deal with like WOT. So these simple OEM designs are often more than adequate for the manifold suction and crankcase pressure situations provided for any engine whether performance or otherwise, as long as you pay attn to the pressure and flow rate. For example I use two or three PCV valves in parallel to enhance the flow rate throughput of my crankcase to keep the engine oil even cleaner. The higher surface area of initial vertical hose also keeps oil droplet should any arise to the occasion from blocking the tube and being sucked up into the pcv valves and thus into the Intake manifold. It is merely a matter of volume and droplet size for the initial condition whether the oil can be ingested or not during an idle/rest condition such as cruise. Very easy to do.
What really matters is WOT. The highest blow-by condition and most hurricane in the crankcase. You must imagine that condition how hard it is to separate oil from air and what the crankcase gas is composed of at WOT.
For starters realize the WOT condition implies 100% of crankcase gas is blow-by which is mostly water and CO2 (99% is). Since there is NO fresh air inlet during WOT condition if the PCV is setup properly for a wet sump. Our goal objective desire is to remove that crankcase blow-by gas as quickly as possible since it is a gas capable of dissolving into engine oil and circulating through the engine leading to deposits and eventual failure. We also must maintain a low crankcase pressure as a secondary objective to keep scalar pressure gradients from dissolving combustion gas into oil and keep pressure out of oil seals like piston rings which will accumulate oil (front main, rear main, valve covers, piston rings, accumulate and eventually leaking oil the opposite direction out of the engine or into the combustion chamber). Notice if we control pressure we are controlling flow for this side of the pcv system since 100% of the blow-by is crankcase gas and by virtue of having a low pressure as with a tire pressure means we have evacuated the gas faster than it is being produced by the piston blow-by. Remember low pressure will reduce blow-by, prevent early ring switching at the end of power stroke, prevent ring flutter, so the blow-by will be kept low by virtue of having a low pressure at wide open throttle. Nevertheless if the piston rings have enormous ring gaps or other issues that should not be (machining errors , broken pistons, or improper engine warm up for ductile low silicone alloy pistons) the blow-by will be tremendous and a wet-sump PCV system may not suffice, the pressure will rise despite efforts and this will force oil from the engine at WOT which is how we know it is broken, something is wrong.
And yall should stop calling it a venturi. I have not seen any venturi in this entire discussion. Its just a term people throw around kind of like differential which is mis-used and abused by people online that don't really know what it is I guess. I mean most of you should know but I wonder why you keep calling it that anyway? The manufacturer of some catch can clearly does not know what a venturi is because that aint it.
This is what you are discussing and visualizing in the intake manifold and tubes in general where there is no venturi, for example my little tube on my turbo is not a venturi
Equation is basically (static pressure + kinetic energy + height) We neglect height because for air in automotive applications height is negligible.
Therefore we only have the static pressure and kinetic energy components. Notice the HGL hydraulic grade line is simply the static pressure tap by itself. The EGL is tapped into the velocity component or energetic gradeline which include both kinetic energy and static pressure together. When you see that little tube positioned reversed in the intake manifold what it is doing is subtracting the kinetic energy portion of the EGL from the HGL which is not a venturi, in order to reduce pressure below HGL. If it faced the other way it would rise to EGL over HGL. The difference being V^2/2g or basically based on velocity. So when is peak velocity? Is when peak drop in pressure.
My tap on my engine has no EGL component nor any venturi, it is purely HGL based.
If the HGL by itself was not sufficient I might consider adding an EGL portion to the inlet tube. The HGL is provided by the air filter which was sold to me based on CFM @ Pressure drop, for example 800CFM @ 1.5"Hg or whatever. SO when the engine demand hits 800CFM or whatever into the compressor wheel my filter provides an HGL of 1.5" Hg which of course due to friction becomes less and less along the tube to the crankcase. In the crankcase I measured around 1"Hg for example when the filter is brand new but it will have more vacuum as it ages which I am depending on. Furthermore if I added tube or a volume to that hose it would kill my HGL and cause crankcase pressure to rise which will cause oil to blow out of the engine from every oil seal including into the air intake and piston rings.
THIS is a venturi.
Notice the neck down portion has the low pressure. Its still an HGL affect, velocity induced the low pressure but the tap typically does not include any EGL or velocity related influence. At least not as shown in my book.
In other words the low pressure is due to the constricted pipe and this means you can tap into the HGL of low pressure here without a pitot.
Well yes. It's being called a venturi because of where it's being located and oriented. It does indeed pull vacuum "venturi effect" because of where it's located with high speed air moving around it to act as a vacuum on the oriented port. BUT you are somewhat correct. The area where it is being installed isn't reduced in size any to increase the velocity on it as the air should already be moving fast enough where it's being installed. Granted turbo or centri being used. It is just a simple angled barb turned and cut specifically to achieve what they're after. It may or may not have an orifice in it to aid in this. I really don't know.
Edit - was just informed that Elite does indeed send out a smaller diameter tube that this is installed into. It's about 1/2 inch smaller than the regular hose piping creating the high speed air and thus the venturi effect. Don't know if this is in all applications or just happened to work out that way in this case.
https://www.eliteengineeringusa.com/...-venturi-barb/
To the first post above. That is talking about a dry sump system in regards to it's pcv system already technically having a way to drain back into the oil sump and removing said oil via an incorrectly installed catch can system in this case will indeed remove the oil from the system and if removed enough times it will lower the oil level. I thought checking oil level was par for course when emptying catch cans? Guess not for some owners if GM released this.
As for vacuum on the crankcase at wot. I know vacuum adds hp. Nascar engines run a single chamber of their oil pumps just to pull vacuum on the crankcase's. It's good for about 70hp on those engines if memory serves. It's been 2 decades since I got to mess with any so I don't remember vacuum levels or anything like that. How much vacuum with wot is safe and how much do you need to make extra power and keep the rings from fluttering?
If that car is yours shown King. Nice setup...
Last edited by GHuggins; 12-19-2023 at 12:00 AM.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Vacuum won't give power when it comes from the pumping loss of the cylinder. E.g. an OEM pcv system no matter how much vacuum it provides will always reduce engine power. It costs power to drive PCV the energy must come from somewhere.
IF there is a turbocharger the turbo can provide the kinetic energy.
If there is a pump (oil pump or vacuum pump or something to derive energy) the exchange rate (mechanical -> Ring sealing) can yield some power beneficial if the ring tension can be reduced. E.g. low piston tension rings are generally required to see large (4 to 8% usually?) gains in power. Although there is still some small (1 or 2% maybe) in typical ring tension applications from OEM when using a dry sump type of oil system which can protect the wrist pins and oil pump from the crankcase vacuum.
To answer your question is depends on the engine. 4g63 2.0L "built" the oil pump will fail with around 8" Hg of vacuum at wot for example. A small block chevrolet could lose its wrist pins around the same vacuum in wet sump. The 2jz and RB engines with piston oil squirts do better with the vacuum but the natural tension/surface area and ring design friction is already inherently so low there isn't much of a sealing benefit to make the cost worth the effort.
The general answer is 1 to 5" Hg of vacuum is safe for all conditions in any wet sump engine, but 5" is starting to push it IMO. Should be closer to 3" or 2". I shoot for 2.5"Hg for example at the end of filter lifespan if possible but quite happy at 1.5"Hg at WOT its fine. You just need some vacuum to scavenging the crankcase blow-by gas to keep the oil clean and protect the ring function from accumulating oil and ruining the engine. Its not about power its about lifespan and cleanliness. Otherwise I wouldn't waste my time here. Having a powerful engine is easy just rip the PCV system off and put a breather on it and let it go to shit. It will make max power that way but it won't last 200k miles. If you want to reach 250k 300k then do a quick cylinder scrub some new rings and a new oil and chain and guides then go again another 300k with the same engine this is how you do it.
If that car is yours shown King. Nice setup...
Thanks. The engine was a free LM7 from junkyard @ 180k their worst one in 2017 my first LS engine- a test engine, it had to be free $0. The goal to test my skills and show how to build a swap properly by using a never seen before engine into a chassis where it does not belong, and use only 1 engine. Everything done myself with no lift or expensive tools. I will make perhaps total 300k miles @ 500-600rwhp (I am at 240,000 so far) then I'll prob take it apart to show example of cleanliness, how clean the ancient engine has become over time just by driving with correct PCV and tuning theory.
Every aspect of the vehicle has been documented so it can be re-created. I do not hold back secrets or my process. I include timestamp for each step along the way.
https://www.yellowbullet.com/threads...river.2559833/
There are many videos along the way and transmission building section, cleaning and preparation, boost pressure testing, crankcase pressure testing, everything done.
First try
And when its a tube positioned that way in the stream that depends on global velocity its called a pitot tube, not venturi
https://www.grc.nasa.gov/www/k-12/BGP/pitot.html
Attachment 140858
Those guys are not engineers they just use the name wrong so its proof. We can get a paper degree and call us an engineer but it doesn't actually mean we understand engineering. The paper doesn't do that for us. But we can still sell products under the guise of engineer.
Look at me I can haz enginearing deg?
Eye so much dags, I can sale catch can nao?
Sure and people would buy it. I'll put a $0.25/ea pressure transducer in it for a digital LCD readout and a warning lamp LED for pressure and a velocity calc so you can adjust your hose diameter optimally using the pitot and a fluid sensor (amplifier with a pull up again the electron drain of touching a liquid with calibrated properties I use this for water cooling shields also) and optional inputs since, you know, microcontrollers have so many might as well use em. But what would I really be doing? Taking advantage of ignorance in the high performance community because all they really need is a fucking short piece of hose.
I want to thank you all for contributing to this thread. Indeed the plumbing was wrong for the catch can. I have put 198 miles on the car so far with some WOT pulls and have emptied 2oz from the can. This is a huge improvement from getting 2 oz every 46 miles. IF this continues to hold true, I can expect to be a little less than 1 qt low upon oil changes. Sound about normal?
Sounds good to me but people doing this all the time on their own cars would be best to reply.
On a side note - 2-3 inches with idle and cruise to the valve cover. Right around 0 all the time with wot at the valve cover with the elite kit. Was hoping for more but at least it's not seeing pressure...
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
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