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What's with the oil catch cans?

BowDown

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I didn’t pay that much for my Mishimoto oil catch can and it has a 7 ounce can. And comes with custom mount and hoses.


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Some catch cans interfere with the functionality of the PCV system and others dont do a good enough job of separating oil vapor from the air flowing through them. I've experimented with many different versions and this one and the elite engineering E2000 and E2 did the best job. Others didnt flow enough and caused gaskets to be pushed out.
One thing I've learned through this is get one with the biggest hose you can get, -10 or -12 if possible.
This size allows for the oil vapor to slow down velocity in the hose and the oil and air to separate. The volume of the can is critical for the same reasons and why cheap small cans don't work, they will catch "some" oil but not all and still allow oil into the intake. There is a difference between them.
Screenshot_20200809-163454_Instagram.jpg
Above is a pic of my car at a Wannagofast 1/2 mile runway event, the smoke caused by the wrong/cheap catch can not flowing enough air and causing excessive pressure in the crank case, the wrong catch can is worse than no catch can. The problem has since been corrected and the car no longer has excessive crank case pressure.
Granted the Ram 5.7 isn't making near the power my car is making but the principle still applies, just scaled down. The price difference between the cans must use on the Ram and what I know works isn't worth the headache to me or doing it multiple times
 

securityguy

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I have this system on my Corvette, gonna buy the same for the truck
Have you looked at the Mishimoto?
 

whetrick1

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Some catch cans interfere with the functionality of the PCV system and others dont do a good enough job of separating oil vapor from the air flowing through them. I've experimented with many different versions and this one and the elite engineering E2000 and E2 did the best job. Others didnt flow enough and caused gaskets to be pushed out.
One thing I've learned through this is get one with the biggest hose you can get, -10 or -12 if possible.
This size allows for the oil vapor to slow down velocity in the hose and the oil and air to separate. The volume of the can is critical for the same reasons and why cheap small cans don't work, they will catch "some" oil but not all and still allow oil into the intake. There is a difference between them.
View attachment 64988
Above is a pic of my car at a Wannagofast 1/2 mile runway event, the smoke caused by the wrong/cheap catch can not flowing enough air and causing excessive pressure in the crank case, the wrong catch can is worse than no catch can. The problem has since been corrected and the car no longer has excessive crank case pressure.
Granted the Ram 5.7 isn't making near the power my car is making but the principle still applies, just scaled down. The price difference between the cans must use on the Ram and what I know works isn't worth the headache to me or doing it multiple times

The Mishimoto can comes with custom hoses. I think they’re 1/2 in I/D. Or maybe 5/8 I/D. You can’t go much bigger than that.


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securityguy

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I think $270 is very STEEP for an OCC. Mishimoto has been the leader in this field forever and the engineering and design of their cans and installation is top notch. I'm sure the MightyMouse is nice to, just unsure how it can beat out the Mishimoto can other then cost.
 

whetrick1

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The Mishimoto can comes with custom hoses. I think they’re 1/2 in I/D. Or maybe 5/8 I/D. You can’t go much bigger than that.


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Check out Mishimoto and see what the difference is and let me know if the 100.00 dollar difference is worth it.


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BowDown

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The Mishimoto can comes with custom hoses. I think they’re 1/2 in I/D. Or maybe 5/8 I/D. You can’t go much bigger than that.


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I have 1" or -12 on my car
 

BowDown

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I think $270 is very STEEP for an OCC. Mishimoto has been the leader in this field forever and the engineering and design of their cans and installation is top notch. I'm sure the MightyMouse is nice to, just unsure how it can beat out the Mishimoto can other then cost.
Check out Mishimoto and see what the difference is and let me know if the 100.00 dollar difference is worth it.


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I've used cans like mishmoto, not enough volume to slow the vapor down and separate/catch all the oil.
$100 for a part is cheap to me and not worth the time especially if you DO have to do it twice. $200 for catch can is about the norm for a good one. If you really wanted to go cheap, get an air compressor line dryer for $40 at Lowe's, I've seen people run them and they do work but not as well a real catch can.
As for the mishmoto, I dont like the simple baffling or the port location, esp the exit port. The configuration of that can seems to me that it would still allow significant oil vapor into the intake.
 

securityguy

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I'm no expert on OCC's, but I did stay at a Holiday Inn Express last night :) I'll take your word for it, but the can is not a $100 can and it also holds significant volume (I think it's about 7-8 ounces). In addition, it has a 50 micron solid brass filter on the exhaust side. You seem to have a lot of experience with OCC's on performance cars so, if you feel it's worth it to you, no argument from me. All I know is that even a $40 can on eBay is better than having nothing and, on HEMI, I'm not sure that spending $270 on a can will return the value just like it may not on the $200 Mishimoto.
 

djants

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I have 6k miles on my truck. After reading and reading and reading. I think I made a decision to get a catch can. Did I already do some “damage” to my engine without it for 6k miles?
 

Chanyote66

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I have 6k miles on my truck. After reading and reading and reading. I think I made a decision to get a catch can. Did I already do some “damage” to my engine without it for 6k miles?
Preventative measures are never too late. better now than never if you choose to install one. If you look at many engines that are still on the road well past 200k without catch cans, The big thing is keeping the oil and sludge to a minimum within the intake, and the burnt oil collection in the cyl's down.
 

securityguy

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I have 6k miles on my truck. After reading and reading and reading. I think I made a decision to get a catch can. Did I already do some “damage” to my engine without it for 6k miles?
As @Chanyote66 stated above...you're fine. I highly recommend the link below.

 

Chanyote66

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I've used cans like mishmoto, not enough volume to slow the vapor down and separate/catch all the oil.

You apparently do not know what molecular separation and angular velocity is, which is critical to any true engine builder. Your statement is correct for a thru pipe and minimally correct for a baffle system, size does help slow flow. But that is just the tip of the iceberg.

The primary volume does help with separation but the baffles and specific angles of vapor flow are the critical aspect here. You can see that the larger multi stage catch cans have "filters" and baffles. The baffles change the angle of flow which causes droplets (vapor is droplets) to impact the baffles and/or the walls/bottom of the can. To do the same thing without baffles and "filters" (the filters are usually brass filters or a steel wool type material) you would need a catch can with a MASSIVE volume and cross section in relation to your primary flow lines.

In regards to your corvette. what pcv lines are used without the catch can? the "upgraded" PCV PERFORMANCE kit I found is -8 and was "rated for" 1000+hp that is for a 1/2" hose which means your -10 is for a 5/8" line and is slightly over-sized, this can cause two things, decreased velocity in the lines which causes separation of vapor, and then cooled larger droplets of oil being drawn into the intake, or an increased flow if you really have that kind of power. Yes a catch can can increase resistance but that is the way they work. if you had PCV issues, maybe go with paralleled catch cans. The actual flow through a PCV system is minimal.

A standard PCV system has a theoretical maximum of 20.543L/min pumping speed thru 4ft of 1/2" ID tubing. that is using the differential pressure of 20PSI, 5PSI maximum observed crank case pressure of a NA and lightly turbo'd engine is 4-6PSI + 14PSI is basically perfect vacuum to atmosphere, which is nowhere near what your engine can do. A properly balanced v8 maintains a theoretical constant pressure since there is always one cylinder volume extending and one contracting at the same time. The added pressure is from blowby, if you are getting so much blowby that your PCV cannot keep up and it is causing reverse blowby of oil and particulates back in past the rings, you have bad rings! Your -10 can flow at a maximum of 25.806L/min or 25% more flow which again can be good and bad depending on path and actual velocities.
 

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You apparently do not know what molecular separation and angular velocity is, which is critical to any true engine builder. Your statement is correct for a thru pipe and minimally correct for a baffle system, size does help slow flow. But that is just the tip of the iceberg.

The primary volume does help with separation but the baffles and specific angles of vapor flow are the critical aspect here. You can see that the larger multi stage catch cans have "filters" and baffles. The baffles change the angle of flow which causes droplets (vapor is droplets) to impact the baffles and/or the walls/bottom of the can. To do the same thing without baffles and "filters" (the filters are usually brass filters or a steel wool type material) you would need a catch can with a MASSIVE volume and cross section in relation to your primary flow lines.

In regards to your corvette. what pcv lines are used without the catch can? the "upgraded" PCV PERFORMANCE kit I found is -8 and was "rated for" 1000+hp that is for a 1/2" hose which means your -10 is for a 5/8" line and is slightly over-sized, this can cause two things, decreased velocity in the lines which causes separation of vapor, and then cooled larger droplets of oil being drawn into the intake, or an increased flow if you really have that kind of power. Yes a catch can can increase resistance but that is the way they work. if you had PCV issues, maybe go with paralleled catch cans. The actual flow through a PCV system is minimal.

A standard PCV system has a theoretical maximum of 20.543L/min pumping speed thru 4ft of 1/2" ID tubing. that is using the differential pressure of 20PSI, 5PSI maximum observed crank case pressure of a NA and lightly turbo'd engine is 4-6PSI + 14PSI is basically perfect vacuum to atmosphere, which is nowhere near what your engine can do. A properly balanced v8 maintains a theoretical constant pressure since there is always one cylinder volume extending and one contracting at the same time. The added pressure is from blowby, if you are getting so much blowby that your PCV cannot keep up and it is causing reverse blowby of oil and particulates back in past the rings, you have bad rings! Your -10 can flow at a maximum of 25.806L/min or 25% more flow which again can be good and bad depending on path and actual velocities.
SWEET...now here's a man that knows what he's talking about...great write up @Chanyote66!!!
 

BowDown

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You apparently do not know what molecular separation and angular velocity is, which is critical to any true engine builder. Your statement is correct for a thru pipe and minimally correct for a baffle system, size does help slow flow. But that is just the tip of the iceberg.

The primary volume does help with separation but the baffles and specific angles of vapor flow are the critical aspect here. You can see that the larger multi stage catch cans have "filters" and baffles. The baffles change the angle of flow which causes droplets (vapor is droplets) to impact the baffles and/or the walls/bottom of the can. To do the same thing without baffles and "filters" (the filters are usually brass filters or a steel wool type material) you would need a catch can with a MASSIVE volume and cross section in relation to your primary flow lines.

In regards to your corvette. what pcv lines are used without the catch can? the "upgraded" PCV PERFORMANCE kit I found is -8 and was "rated for" 1000+hp that is for a 1/2" hose which means your -10 is for a 5/8" line and is slightly over-sized, this can cause two things, decreased velocity in the lines which causes separation of vapor, and then cooled larger droplets of oil being drawn into the intake, or an increased flow if you really have that kind of power. Yes a catch can can increase resistance but that is the way they work. if you had PCV issues, maybe go with paralleled catch cans. The actual flow through a PCV system is minimal.

A standard PCV system has a theoretical maximum of 20.543L/min pumping speed thru 4ft of 1/2" ID tubing. that is using the differential pressure of 20PSI, 5PSI maximum observed crank case pressure of a NA and lightly turbo'd engine is 4-6PSI + 14PSI is basically perfect vacuum to atmosphere, which is nowhere near what your engine can do. A properly balanced v8 maintains a theoretical constant pressure since there is always one cylinder volume extending and one contracting at the same time. The added pressure is from blowby, if you are getting so much blowby that your PCV cannot keep up and it is causing reverse blowby of oil and particulates back in past the rings, you have bad rings! Your -10 can flow at a maximum of 25.806L/min or 25% more flow which again can be good and bad depending on path and actual velocities.


So, you took the long way around stating the differences between a catch can and a good catch can...which I stated without all the sci-fi stuff.
You can quote all the theories you want, I"VE DONE IT and had to do it twice, I know what does and does not work for instance, does your theory and math take RPM into consideration?
I can tell you for fact that the crank case pressures of a N/A engine and a Turbo engine are no where near the same, does your math take ring gap into consideration? There's far too many variables involved for your one size fits all theory for instance, your comment of
The added pressure is from blowby, if you are getting so much blowby that your PCV cannot keep up and it is causing reverse blowby of oil and particulates back in past the rings, you have bad rings!
is incorrect, RING GAPS.
My engine is an ERL 434 ci'" LS, the ringaps are set at .0024"'s, a stock engine will be closer to .0019" for the top and .0021" for the second why, thermal ring expansion. A boosted turbo or SC engine will be at .0024" - .0026".
My car makes 600 rwhp NA on 93 and 629 rwhp on E85 and through the new evac system, no smoke
Now, you can quote whatever math and theories you please but after taking corrective action to my car, guess what I no longer experience?


As to this comment
the "upgraded" PCV PERFORMANCE kit I found is -8 and was "rated for" 1000+hp that is for a 1/2" hose which means your -10 is for a 5/8" line and is slightly over-sized, this can cause two things, decreased velocity in the lines which causes separation of vapor, and then cooled larger droplets of oil being drawn into the intake, or an increased flow if you really have that kind of power.
I'll let the video above speak to the power, as to the oil in my intake comment, ill let the pictures do the talking

20180711_155113.jpg 20180711_154821.jpg 20180711_154801.jpg

See any oil?
 
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Chanyote66

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See any oil?

You obviously rebuild quite a bit and work on the engine more than the average driver. so there will not be any oil buildup since it would be cleaned and maintained. Hook up 10k# behind it and run 100k+ miles... then check your intake for oil...

RPM does not come into account of calculated maximum flow of a tube. RPM would actually provide a reduced flow due to duty factor of the pumping. you would have to account for the acceleration and deceleration of the pistons, then calculate the active pumping vs stagnant pressure time.

It is not always ring gaps that can cause blowby... ****ty rings, which you probably do not have with a specifically built engine, or out of tolerance rings can cause this.

the big points here are:
1: 99% of the truck owners are not out for a big **** contest racing people on the roads, they just want a clean well running engine.
2: I doubt the guys on here talking about a catch can are running prochargers.
3: Differential pressures are MASSIVELY different in a non NA engine and need to be accounted for. Yes, you may have got the wrong setup for your build, but a stock bolt in accessory will work on a stock configuration.
4: we are not talking about chebbys here. ;) (I know engines are engines :ROFLMAO:)

If you are worried about an underperforming catch can, go buy the one off the hellcat... done
 

BowDown

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You obviously rebuild quite a bit and work on the engine more than the average driver. so there will not be any oil buildup since it would be cleaned and maintained. Hook up 10k# behind it and run 100k+ miles... then check your intake for oil...

RPM does not come into account of calculated maximum flow of a tube. RPM would actually provide a reduced flow due to duty factor of the pumping. you would have to account for the acceleration and deceleration of the pistons, then calculate the active pumping vs stagnant pressure time.

It is not always ring gaps that can cause blowby... ****ty rings, which you probably do not have with a specifically built engine, or out of tolerance rings can cause this.

the big points here are:
1: 99% of the truck owners are not out for a big **** contest racing people on the roads, they just want a clean well running engine.
2: I doubt the guys on here talking about a catch can are running prochargers.
3: Differential pressures are MASSIVELY different in a non NA engine and need to be accounted for. Yes, you may have got the wrong setup for your build, but a stock bolt in accessory will work on a stock configuration.
4: we are not talking about chebbys here. ;) (I know engines are engines :ROFLMAO:)

If you are worried about an underperforming catch can, go buy the one off the hellcat... done


The intake has been off once and that was to check a vacuum port connection, 99% of truck owners don't give a crap about a catch can and will never run on. What you have here is a forum where enthusiast congregate. The consensus HERE may be they just want a clean running truck but this forum likely represents less than 1% of buyers so, wrong.

If the rings were bad, your words, where the smoke? In my build and likely in the 5.7 HEMI as most modern engines, any "blow-by" is from the ring gaps and not bad rings.
RPM very much does play a role because the increased piston speed (frequency of strokes per min) will increase the volume of air in the crank case. IE an engine idling will have less air in the crank case thus a smaller hose/PCV system could keep up. Add more rpm and sustained RPM and that same system cant keep up so yeah, RPM factors in.

As for
"Hook up 10k# behind it and run 100k+ miles... then check your intake for oil..."
My stock 2003 Ram has 277K on it, it broke a valve spring last winter and miss-fired and blew the intake apart. When I pulled the intake, NO CATCH CAN ever, it was full of oil and not from bad rings. Additionally, you think there's less load on an engine turning 5-7500 RPM for 30-45sec multiple times a day, multiple times a week, multiple times a month for years on end than a 10k loaded 100k mile truck? LOL OK.

Chevys vs Dodge engines? Engines are air pumps, they all do the same thing the same way with no knowledge of the make they are in.
BTW, my car is N/A, not procharged so the principle is the same, just scaled back for stock vehicle and I never said the Mighty Mouse system was needed on these trucks, I said its what I will run. I prefer an overbuilt combination vs one that will work.
Fact is, you thought you needed to step in and correct someone with your "molecular separation and angular velocity" science. I deal with people like you all day every day whether its relative to high performance or in my day job of IT. Everyone of you guys has your "best practices" and formulas but have never put them to use in the real world where there's 1000's of variables and almost every time, you guys ideas don't work out in the real environment.
Ex, you claimed my PCV system would cause oil in my intake and that my rings where possibly bad, both proven wrong so you craw-fished in to some BS maintenance as to why my intake was clean. I built this car to beat the pi** out of and that's what I do, I didn't build it to have to work on every week and I don't.

I'm not in the least concerned about the performance of the catch can, I stated my preference, period and that not all were the same. Lastly, Hellcats don't come with a catch can soooooo.
 
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Chanyote66

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The intake has been off once and that was to check a vacuum port connection, 99% of truck owners don't give a crap about a catch can and will never run on. What you have here is a forum where enthusiast congregate. The consensus HERE may be they just want a clean running truck but this forum likely represents less than 1% of buyers so, wrong.

If the rings were bad, your words, where the smoke? In my build and likely in the 5.7 HEMI as most modern engines, any "blow-by" is from the ring gaps and not bad rings.
RPM very much does play a role because the increased piston speed (frequency of strokes per min) will increase the volume of air in the crank case. IE an engine idling will have less air in the crank case thus a smaller hose/PCV system could keep up. Add more rpm and sustained RPM and that same system cant keep up so yeah, RPM factors in.

it was full of oil and not from bad rings.
Chevys vs Dodge engines?
wheres the smoke? in your picture :ROFLMAO:

RPM again has no factor in the MAXIMUM FLOW through a tube... RPM does not increase the volume of air... if it did all engines would balloon up when revved... it does however increase the potential blowby and pressurization due to this. but your PCV hose is still the same size... unless you have a "sequential short throw double clutching pcv hose" ;)

My magnum intake was full of oil too (160k miles)... and the main culprit from that is the PCV system... or the issues sometimes with the plenum leak. the PCV is helped by the Catch can, thats all, its not a magic fix all.

Chevy vs Dodge... you didn't get my hint it was a joke... I know they are all air pumps.
 
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Chanyote66

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"molecular separation and angular velocity" science. I deal with people like you all day every day whether its relative to high performance or in my day job of IT. Everyone of you guys has your "best practices" and formulas but have never put them to use in the real world where there's 1000's of variables and almost every time, you guys ideas don't work out in the real environment.

"molecular separation and angular velocity" is commonly researched in engines, why do you think fuel injectors have changed and are more precise? why is direct injection more powerful than port? why are exhausts not square corners? why would you "Port and polish" an intake where the roughness of the inner and outer path are different? Why is a dry sump the ultimate go-to oiling system? all of those are real world proven evaluations of "molecular separation and angular velocity" wizardry ;)

Im not saying your corvette is a bad build. I enjoy the sound of a nicely tuned engine and drivetrain. and again... as you realized, not all parts work together. you may have had an overly restrictive catch can, never denied it, and its great to have the input that you had a bad experience with one, so others can know what to watch out for.

BTW there is probably a v6 mustang with an underdrive pully kit that said he can beat you :ROFLMAO:
 

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