Will this catch can idea work?

[Aproductions]

Alright so I wanna to the 2 oil catch can method.

1 from the intake manifold to the PCV valve.

1 from the intake to the side of the VC.

I want SS lines and An fittings from the cans but since I can't AN my PCV valve or anything would it work to just cut some of the SS part away and use it like a regular hose?

 

[dexterholland04]

STM makes a fitting for this.

STM ALUMINUM VALVE COVER -AN FITTING | 90-99 DSM

Go that route and do it right the first time!

 

[Aproductions]

it was just a picture to show an example.

I am talking about the PCV valve

 

[phatTSi]

In my personal opinion -6 is way too small for this. At the very least a -8 should be used but the bigger the better. The STM fitting is no better than the stock set-up because it doesn't increase the amount of crankcase pressure relieved.

If you want to run an fittings then you'll have to have an fittings welded on. If you don't use the proper hose ends then the stainless braids are just going to fray and look awful.

 

[Aproductions]

it couldn't fray if I zebra clamped it right at the end.

Also I am only gonna have like 500 or less hp. Can't I do -6an?

 

[DSM nOOb]

In my personal opinion -6 is way too small for this. At the very least a -8 should be used but the bigger the better. The STM fitting is no better than the stock set-up because it doesn't increase the amount of crankcase pressure relieved.

If you want to run an fittings then you'll have to have an fittings welded on. If you don't use the proper hose ends then the stainless braids are just going to fray and look awful.

I agree with this. No offense to stm I just feel like that one fitting will not do anything close to what should be used. On my race car I have 4 -10 lines off the vc

 

[Aproductions]

Well I will use -an fittings but I can't because of the PCV valve, also you need to run a check valve too.

How would I do that?

 

[phatTSi]

For your goals 2 -10 off the valve cover to a sealed can with a -10 plumbed back into the intake pipe would suffice. I'm just finishing my catch can setup and I can post pictures tomorrow so you can get an idea of how I did mine.

 

[Aproductions]

what about the PCV valve to the intake manifold, wont oil and stuff still get through my pipes and stuff?

 

[1990AWD]

What I believe he's saying is to ditch the PCV and run two lines from the VC to a catch can and one line from the catch can to intake (pre-turbo). Then cap off the old PCV nipple on the intake manifold.

This is what I'm going to do also. It gives no chance of boost leaks and provides better ventilation when in boost because the vacuum increases instead of decreasing.

 

[Aproductions]

What are the setbacks of this way?


I am interested but this car will be driven like a daily driver for the warmer half of the year.

(may to october-ish)

 

[rollover-tsi]

i like your ms paint picture. made me laugh. good luck with the catch can, im fabing one right now, ill let you know if it works

 

[Aproductions]

Is it okay to delete the PCV valve?

 

[GRAVEDIGGER]

Is it okay to delete the PCV valve?

It's there for a reason, so I would leave it. You want to have a way to pull vapors out of the crankcase which is what is happening when your car is at idle. The intake manifold is pulling a vacuum therefore pulling out the vapors in the crankcase. Then as you build boost in the intake manifold the PCV valve checks off/closes so that the pressure doesn't come back the other way into the crankcase.

If you were to do away with it you would have to do like 1990AWD says. This way the intake to the turbo will create enough vacuum to pull the gasses out of the crankcase. Not being able to pull the gasses out is a if you ask me on any kind of a daily driver.

 

[Aproductions]

Which is better?

Also do bigger lines make more oil in the catch cans?

 

[Jiggalude]

I have my car setup with your first diagram. I bought two cheap catch cans off ebay and I had to seal them myself because my car wouldn't hold vacuum before I fixed them. I think the first diagram is fine, the second one is probably overkill for what your plans are.

 

[Aproductions]

So the best way is to buy 2?

How am I going to use SS lines though because of the pcv valve and the check valve?

also what -an size? 8 or 6 or 10

 

[GRAVEDIGGER]

I use the 2 catch can setup like in your second picture. The only difference is I don't run the line back into the turbo intake. Instead I run a breather filter on that side of the can.

You would be surprised at how much gets collected in the one between the v/c and the intake manifold. When your car is idling and warming up there is a TON of nasty crap that gets caught in that can. The intake manifold is the best source of vacuum for evacuating this crap from the crankcase and that's why I choose to run mine like that.

As for the ss lines, I think that's overkill especially with an fittings. Put some hose clamps on the end and forget about it.

 

[Aproductions]

Yeah I will do the 2 catch can method, but I am redoing the bay and the SS lines are a nice touch.

Anyways what size AN fittings? 6,8,10?

Also does having bigger lines suck more oil through?

 

[phatTSi]

This is an area where bigger will almost always be better. I wouldn't even think about going with a -6 for this. I did two -10's on my valve cover and I suspect that it will suffice for my needs.

 

[Aproductions]

So its either -8 or -10 but does having the bigger ones pull more oil through? I don't wanna have to change/add oil all the time.

Also Which way should I go 1 or 2 can ?

 

[bjones18]

With regard to catch-can plumbing, am I missing something? It seems the stock is insufficeint due to need for more flow volume. The most effective way to increase flow volume is vent tube diameter.

Many people are using braided SS lines and AN fittings, which look nice, however are designed for retaining high pressure. The catch can lines are under low pressure, and the "line size" may be more effectively put to a thinner tube wall (that won't kink under vacuum) which gives more flow-area for a given OD. Since flow-area is squared from radius, increasing the tube ID is more effective than running multiple lines.

Am I missing something here? Is there a need for remote mounting? Would there be an issue with a hard-mounted close catch can with a 1/2" thin-wall, straight hard line?

 

[1990AWD]

With regard to catch-can plumbing, am I missing something? It seems the stock is insufficeint due to need for more flow volume. The most effective way to increase flow volume is vent tube diameter.

Many people are using braided SS lines and AN fittings, which look nice, however are designed for retaining high pressure. The catch can lines are under low pressure, and the "line size" may be more effectively put to a thinner tube wall (that won't kink under vacuum) which gives more flow-area for a given OD. Since flow-area is squared from radius, increasing the tube ID is more effective than running multiple lines.

Am I missing something here? Is there a need for remote mounting? Would there be an issue with a hard-mounted close catch can with a 1/2" thin-wall, straight hard line?

If you mounted it directly to the valve cover it would kinda be in the way of stuff, plus it would also be moving with the engine. Mounted it elsewhere, like say where the battery used to be keeps it tidy and out of the way.

 

[Aproductions]

Okay, but should I do the 2 can way or the 1 can way? thanks.

 

[bjones18]

sorry about the two subjects here.

A. should I use two or one can: generally when there are two accepted methods of designing/building something, the execution of the design/build is more important than the choice of which one.

B. I was thinking a catch can off the valve cover might be a cleaner package - fewer lines running around
And on the third subject: will a certain design make you add/change more oil? Generally speaking, we are sucking vaporized "blow-by" out of the crank case. If you would like to leave this mixture of gas & oil in your pan, I guess you might use less oil in the short run... however unburned mixture in your oil is not a good lubricant anyway, and may lead to quicker lubricant-film breakdown and may as well be sucked out into a catch can.