Thoughts on catch can after tune?

g2full · November 1, 2019

Lots of good info around for catch cans, and tunes on here..

What's the thoughts on needing a catch can after tuning out the AFM? I would assume that the need is still there with these being a DI motor....

15 Silverado 5.3

HeySkippyDog · November 1, 2019

Yes, you will still benefit from the use of a catch can. Tuning out V4 and using a catch can is preventative from 2 different directions.

Disabling V4: No collapse/pump-up cycling of the lifters.

Catch can: Greatly reduced oil vapor sprayed at the intake valves.

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g2full · November 1, 2019

That's what I figured. Just ordered my Autocal yesterday while the truck is having lifters and pushrods replaced at the dealer.

Catch can will be next.

Thanks!

1SLOW1500 · November 1, 2019

There is still some misunderstanding on catch cans. And I see a lot of people I stalling them incorrectly. Also the 2nd issue is breathing. Some people skip the 2 breather tubes to the intake tube. Others but a css but still leave line to intake.
Depending an what you.i stall and how you install it there is different percentages of efficiency. Or even making it worse.

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g2full · November 1, 2019

7 minutes ago, 1SLOW1500 said:

There is still some misunderstanding on catch cans. And I see a lot of people I stalling them incorrectly. Also the 2nd issue is breathing. Some people skip the 2 breather tubes to the intake tube. Others but a css but still leave line to intake.
Depending an what you.i stall and how you install it there is different percentages of efficiency. Or even making it worse.

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This is definitely the first time I've had experience with a catch can. I'm looking to make the truck last a while.

Some of the threads on both tuning and catch cans have GREAT info, but are 70+ pages.... which is great bathroom reading material but can also be a bit overwhelming.

Some of what I see makes the process and install seem simple, and others not so much.

1SLOW1500 · November 1, 2019

It is more so common sense and also a understanding of what is being cleaned and what the engine needs.
Also there are 3 basic setups.
1- one in one out cans. Cleans only the valley cover to the intake line.
2- css this allows for more valve train side venting and also has a seperator in it.
NOTE: both these setups do not address the two tubes that go from the valve covers to the intake tube.
3- 3port can. One is vaccum(intake manifold) other two are valley cover and css. But in this setup passenger tube goes over intake and plugs into driver side then css goes to can.
3 is the best and best coverage. On force induction we need to go more.
Afm disables is best and will allow for most vaccum. Check valve are not needed in a natural aspirated setup.

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Ozer · November 1, 2019

Mine is the simple way. One end goes in other end goes out, in the middle is the catch can. Its been collecting lots of vapor/oil and such for almost 2 years.

Im sure there are different ways of installing it.

1SLOW1500 · November 1, 2019

Mine is the simple way. One end goes in other end goes out, in the middle is the catch can. Its been collecting lots of vapor/oil and such for almost 2 years.
Im sure there are different ways of installing it.

You are good but what of the valve covers to intake tube? Those two line are also allowing oil mist into the intake and tb.
Css allows for a large amount more "breather". As we have seen pressure on stock engines blow out rear main seals. And best is option 3 or as we see in force induction just breather tanks and all intake capped off, then 100% of oil can't get back to engine.

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Doublebase · November 2, 2019

14 hours ago, 1SLOW1500 said:

You are good but what of the valve covers to intake tube? Those two line are also allowing oil mist into the intake and tb.
Css allows for a large amount more "breather". As we have seen pressure on stock engines blow out rear main seals. And best is option 3 or as we see in force induction just breather tanks and all intake capped off, then 100% of oil can't get back to engine.

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I would think an easy solution to determine if you need a 3 phase can is to remove the air snorkel and inspect for oil tracking into the throttle body.

It's already a long journey for that oil to track up and in there, no? Any oil that does sneak through that portion of the system during wide open throttle or whatever, will likely get caught in the various ribs and bends in the air intake - I'm not saying all of it - but by removing the snorkel to the throttle body you could inspect it and tell if you need something like that to improve your situation.

I do use a catch can by the way. It catches stuff, I'm pretty happy with it I guess...I'll probably pull my intake manifold at 60k and do a manual cleaning of the intake valves...and if I do ever see some oil tracking into the throttle body I might look into some clean side separation.

1SLOW1500 · November 2, 2019

I would think an easy solution to determine if you need a 3 phase can is to remove the air snorkel and inspect for oil tracking into the throttle body.

It's already a long journey for that oil to track up and in there, no? Any oil that does sneak through that portion of the system during wide open throttle or whatever, will likely get caught in the various ribs and bends in the air intake - I'm not saying all of it - but by removing the snorkel to the throttle body you could inspect it and tell if you need something like that to improve your situation.

I do use a catch can by the way. It catches stuff, I'm pretty happy with it I guess...I'll probably pull my intake manifold at 60k and do a manual cleaning of the intake valves...and if I do ever see some oil tracking into the throttle body I might look into some clean side separation.

I see what you are saying. However if you search her you will see people post pics of there tb and the blade is covered. Also what is the point of buying a css and running that to the can also if if the other two lines remain? Again you gain more venting. But the oil issue isn't addressed. By jumping the covers and then out the css to the can you are double cleaning. And with the line not in the intake at all there is no way there would be oil in there.
Also most people don't speak of the water that is in there also. We mount the can off the brake booster so it stays warm. Even stock there is a picture of frozen lines.

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Doublebase · November 2, 2019

3 hours ago, 1SLOW1500 said:

I see what you are saying. However if you search her you will see people post pics of there tb and the blade is covered. Also what is the point of buying a css and running that to the can also if if the other two lines remain? Again you gain more venting. But the oil issue isn't addressed. By jumping the covers and then out the css to the can you are double cleaning. And with the line not in the intake at all there is no way there would be oil in there.
Also most people don't speak of the water that is in there also. We mount the can off the brake booster so it stays warm. Even stock there is a picture of frozen lines.

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Ok, fair enough...if there are instances with oil tracking through the throttle body I can see the point.

I'm not sure I understand the benefits of a clean side vent off the oil cap, unless you're saying that this is a poorly designed crank case that needs additional venting...there's around 5 million of these engines driving around on the roads...I haven't heard many stories of rear main seal leaks due to too much pressure. Will that vent reduce pressure and perhaps reduce the amount of oil being drawn into the engine? That's something I'd be curios about. You actually hear some people under fill their engines with oil to prevent oil being drawn into the intake (not something I'd consider but I've heard of it). There's also the thought that GM requires 8 quarts because they know these engines draw oil into the intake.

flyingfool · November 2, 2019

i'm just filtering the PCV line, running techron fuel for the injectors, and sea foaming every oilchange... the two valve cover breathers barely bypass any oil , since my truck is a daily driver gently used, I dont rev high and drive easy . no oil issues before or after the Throttle body.

I've done testing on the breather ports, using a centrafugal oil trap separator from a BMW , and after 4000 miles i only caught a teaspoon of oil, all the oil passing was thru the PCV port from my testing. mind you if i was running a turbo, i would be seeing much more oil from the valve cover breathers.

If you disable the AFm, does this mean you can do away completely with the vacuum pump assembly?

Edited November 2, 2019 by flyingfool

1SLOW1500 · November 2, 2019

No vaccum pump is for brake booster. But I see what you are saying. The intake pulls enough vaccum to run the booster. But as silly as this sounds what would you do about the oil that would get into booster.
Yes 8quarts is to help the rms to not blow out. I have the new version of rms as mine blew out at 130mph. I also run 7quarts after a oil change then measure and add. But that is to allow additives to soak in and because there is always oil remaining in the motor. It doesn't hurt anything still plenty of oil in there.
There are 2 groups of thought. One neutral venting or breather. Then vaccum pulling out. Vaccum is best and is proven to help engine and make more power. Also it addresses the oil mist better. This would be your css to can and can out to a vacuum source.

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flyingfool · November 2, 2019

GM has been running the booster off the manifold vac for years, once the cyclinder deactivation is removed , you always have ful vacuum for brakes

speaking of vacuum on the engine case, i've seen a guy build a crank case evacuator blower using tiny turbo and a rc brushless motor, which would spin the turbo to 25,000 rpm, and he tied it to the valve covers on his boosted car. i never followed up with him on it , but i'm curious as how it worked in the long run. anyway just a crazy thought im passing it on

Edited November 2, 2019 by flyingfool

1SLOW1500 · November 2, 2019

You see vaccum pumps in big power cars more so on natural aspirated. All the boosted cars have huge breather tubes and a breather tank or run the lines to back and you see "steam" out the rear deck lid.
I know they have ran the booster of the manifold. But now there are concerns of oil. Dont know if that is because the water thin oil or the build of the booster.
Also big cams have issues building enough for the booster so they again run a electric pump. See the lt1.

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