So last night Rob C and myself had a good chat about Catch Can setups he educated me on how it is supposed to work and best ways to do it. This morning I did some research and have found some great information. Here is where my issue arises. Lately, until yesterday, my belief was that for race setups it was just best to have a line from the pcv go to a breather catch can and then to the other valve cover breather, now that I have learned a lot more about how the PCV System works, it doesn't make sense to me as to why someone would switch to something like this (diagram below shows what I am referring to, also the diagram that my setup is based on currently). So my question to all of you who are doing this, why are you doing it?


Source: http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

It is easy for one and keeps the intake and etc... clean with next to no maintenance (only thing you need to do is empty the catch can, not filter media).

When you are idling, there should be next to no blowby, and when you are boosting, would you want to run the chance of throwing droplets onto your compressor wheel?

With my atmo can setup, I'm running two -10 AN lines to the vented catchcan. After a while I get a weird foamy/creamy mixture in it.

How much boost are you running currently?

Any chance you can give us a picture of your setup?

My set up is simaler to that but I run a line stright from my J-pipe from off my turbo stright to a MBC then stright to waste gate. My BOV has it's own line and my catch only has one line going to it. The other valve cover line I removed the PCV valve and replaced it with a one way check vale I got from Ziggy

I have plans to switch to the ECMlink boost controler eventuly.

So you still have your check valve running into the intake?

Afermative
my catch can only has on inlet on it so I would have to up grade befor I can change my setup to vent more crank case presure.

But I have other things I need to upgrade first I got to replace evering from the frame down and get it all powder coated and I got a thermal problem I got to fix as well running over 200 F coolent temps most the time

how far over? I am usually that high around 205

It may be running hot but is running well!! Went for a spin in it last night!! Woohoo a working DSM in my driveway

Nice, glad to hear it Jason!

It was Kents vehicle not mine yet still made me smile to get in a fast Talon

Oh haha, I read it too fast. Glad you guys met up!

As Andrew stated. It is easy to do and keeps everything clean. PCV is only another emission device. Yes it supplies 25% of idle air, but that can be adjusted. Years ago they used to have valve cover beather and road draft tube any blowby would just vent and any oil would just drip down to the road.

So what about crank case pressure?

not sure of your question? without a PCV and catch can? cans are usually vented.

Bryan, was running about 18-24psi on my eaby evo 3 16g. I have since changed to a HX35 with the Tial wastegate set to minimum of 20psi.

I'll grab a picture when everything under the hood is reassembled, but my VC had the old holes welded shut with two -10an 90s welded to the top aimed towards the passenger wheel. Right now my modified RTM special catch can is sitting "loose". I'm eyeing up where my fusebox used to be and getting a box to fit there for a more permanent, natural, install, or else I'll put it down by my new coolant res and leave that spot for my NHRA approved meth bottle

hahaha, that sounds like a good way to do it.

So Stephen, from what Rob and I discussed last night, and from that source on my first post. The way the PCV system is supposed to work is that the intake is supposed to suck positive pressure and gasses out of the crank case. Most people just do a vented catch can like the one pictured, this will only allow the car to vent when there is positive pressure in the case.

My setup will one day will look like this when I get some moneys together, it's the one called Max Pressure Relief.
http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

Right. The pcv sucks vapour but only at idle or light load when there is manifold vacuum. That link is good info but IMO just a waste of money. Are you keeping your EGR valve? If not why not it is a much better emission device then a PCV. Yes PCV slightly helps the oil for getting contaminated. But really all it does it not let HC's vent to atmosphere.

Really the whole point of a catch can is to keep oil off your compressor wheel and out of your IC.

I personally just have a filter on the breather side and have never had oil drip out. (in the last 18 years since it has been installed)

The setup I said I wanted is setup so that there is always vacuum, you basically have your two outlets on your valve cover and then filter and then a line that goes to your intake.

Ok i have read your link 3 times now. Could you please highlight where it says you have vacuum all the time.

Beside that why do you care there are many other mods you can do without worrying about a bit of oil in your intake.

Positive presure will push out your dipstick or vent through your VC Filter or catch can.

If you are talking major power and boost levels then i could see you want some fucktacklar catch can, but for now i don't see the point.

Stephen, during vacuum in the intake manifold (idle), the pcv valve will allow the vacuum to pull the blowby into the IM.

During boost, the pcv closes, and the area in front of the turbo turns into a vacuum, that is the other source of vacuum.

Bryan, the maximum configuration from that link is not providing any vacuum at idle, or not enough to count for blank all; vacuum at idle only happens after the throttle body plate, the rest of your intake piping is close enough to atmospheric. When you are boosting, creating more blowby, do you think the vacuum in front of the turbo is going to help all that much, especially considering that air is moving at a hell of a rate? Hose sizing is more important than anything.

From what I can get from the article, all a 'high-efficiency' catch-can does for you is extend your oil change interval. If you still change your oil regularly, a super efficient catch-can design isn't going to be that much of a benefit. I'd rather have the clean intake than recycling blowby.

Glad the drive made you smile Jason. Now We just need to get your baby switched into beastmode

This was the kind of conversation I wanted. The intake manifold is definitely going to have much more vacuum than the intake will that's for sure. I look forward to seeing your setup Andrew, I think that may be just what I run. Any chance you could walk me through the process of installing the two -10an 90s?

Andrew you don not have to explain PCV operation to me. I was asking Bryan where his other vacuum was coming from. To me any big dollar catch can is useless.

The little vacuum that the intake (pre turbo) syphons will pull oil into your intake and make everything oily.

Just put a breather filter on it and call it a day. Yes the are nice looking but a waste of money IMO.

In the case I am talking about is from the intake, the same vacuum that pulls gasses out of the baffle pre turbo in the stock setup, if the catch can is there, (this setup requires a baffle in the catch can aswell), the gasses will be pulled from both outlets on the valve cover during boost.

Sorry, thought you were asking in general where the vacuum during boost came from for some reason.

Buy a VC from Mike @ Brightside



I'm not entirely sure if there is much benefit on using the vacuum of the turbo intake to help draw the gasses out. The gasses want out, and if you give them two well sized hoses to vent out, the added draw from the turbo will be negligible.

This is the catch can I currently have, but drilled and tapped a breather filter into it to make it vented.


courtesy of RTM racing website


moreless the same 90s out of the top of the valve cover.

Hey andrew when you get a picture I would love to see, that is the same catch can as I have and was planning on doing the same as what you did, I already have a breather filter too.

Looks like i need to make more of these valve covers when i get back! Will be hunting down some cores as i believe i don't have any left.

I believe i have one -8 cover in stock locations that i could sell also if someone doesn't want to go an extreme as the -10 on top.

Ive got 2 mitsi vc's, You could have,... if you weld some large barbed hose fittings on 90's like that pic on my valve cover..

Jay, if Mike does the AN 90's they have AN barb fittings you should be able to throw on.

I was trying to be cheap tho.. If all he has is an fittings, Ill just clamp my hoses to them hehe, Its just a breather hose. I assume they will clear the hood.

There is defently a benefit to having a sealed cath can hooked up to you intake tube, it may not always seem like it, but Mitsu did know what they were doing, when they designed the crank case vent. Adding vacuum vs just having a couple vented lines can defently make a difference. There's some good write up's on thie subject on tuners, for those who care.


Edit: For those that can't search, believe this is the one I'm talking about:
http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

Yeah Daren, that's the one I had posted up as my source. Some good information.

So how are you going to end up doing it?

Are vented catch cans better or worse? I just want to have a system that works and is safe for my car..
right now i have a vented catch can from the top Valve cover to the side basically in a loop
any pointers?
Thanks guys!

I think a lot of guys run it that way.

In the long run I will probably go with a baffled catch can, two lines from the valve cover to the catch can, baffle in catch can, nipple on intake, that's the way the air will flow.

I am not in a rush as I am not pushing big boost numbers, best way to check if it would be of value to you is to get a boost gauge and read your crank case pressure when you are boosting. If it is high then you should probably go with a baffled setup, if not then you will probably be ok.

with it the way i have it. the stock system isn't even working is it? theres no vacuums sucking air in its just in a loop? am i right?

i don't know about your setup christian but a picture is worth 1000 words.

on a similar note, the 1g JMFAB catch can setup is by far the BEST LOOKING setup for the $. Unfortunately, they don't have a custom vented can like that for 2g's.

http://www.jmfabrications.com/store/product_images/k/974/3__93092_zoom.jpg

Yes Christian that is correct, It basically just wofts out, if you are lucky

Mike my issue with that though is that if I am going to pay money for something like that I would like it to work correctly.

Pay for a catch can....

I made mine from ABS with steel wool as my baffle.

Making one for the coolant to match and tring to make a power steering res to match aswell.

The intake nipple isnt gonna suck the gases out as much as most think. its gonna suck from the path of least resistance ,and the huge 3" airfilters dont have much resistance compared to a tiny hole filled with thick gas.

I had a really bad ring in my old 1g, it had lots of blow-by...witch should have been fixed by sucking it into the intake, but it didnt help at all. I had a line to the intake and the PCV port open, and it came out the PCV instead.


Intrestingly tho..

GMs quad 4's came with a catch can thing, that took the blow by, heated it with an electric prob to evaporate the condensation and then drained it back into the oil. This box could fit on a plastic NOS enery drink bottle and be mounted into a saturn engine bay , hooked up to a 12v source.