I think the haters don't understand how venting in front of the turbo is beneficial. I don't want to get into a lot of math, but broadly speaking the flow (aka rate of crank case evacuation) is proportional to; the potential difference (difference between crank case pressure and whatever you're venting into's pressure), inversely proportional to the length of the line, and exponentially proportional to the radius (and thus diameter) of the line. Boiling all that down for our case, increasing the line size helps evacuation and plumbing it back to the intake pre-turbo also helps evacuation independently. If you use larger lines and vta, you might achieve good ventilation, and if you use smaller lines and vent to intake (which is below atmospheric pressure and literally sucks the air out of the valve cover) you might indeed achieve the same good ventilation! Science!!!


IMHO I prefer not venting into the intake because no catch can is 100% efficient, although some are better than others. Inevitably some oil still gets into the intake and slicks things down in your intake pipes and intercooler, lowering it's efficiency. But apparently FP turbos are dependent on such low crank case pressures that something like this is necessary.

 

I'm thinking the Stm can is the way to go, however one more question for all. How about running both valve cover ports to a sealed can, that is then vented to the pre turbo intake. The intake manifold port would be capped. Basically like the buschur can, but without the dipstick drain situation. In fact if I went this route, I might use the buschur can, but not the dipstick tube. I know they say it's not an issue, but I just don't like that e85 water junk going back into the oil pan.

 

You could do that, but there are 2 issues. 1. There is a pcv check valve thats pretty restrictive, but you could replace it with a larger diameter fitting. But more importantly 2. there isn't the same level of baffling here as the driver's side front port, so your catch can will be seeing more oil pushed into it under boost. Honestly I think if you do the tscomp mod on the front port AND run a single circuit sealed system from this front port into the intake you would be golden. Tscomp already has 100% confidence that his mod with a breather (vta) is already more than sufficient, so I can't see how you would have much more problems if you do his mod plus a sealed circuit. I'd cap the rear circuit just cause I do often see a lot of oil going out that side.

For reference, I have a saikou michi dual circuit sealed catch can setup on a stock block / stock turbo running 24psi. On cruising / DD I see a lot of oil/water mix in the rear circuit. I drain half a cup full with every oil change (3k miles). The front can never accumulates oil UNTIL I do track days where the car is on boost 50% of the time for 20 minute sessions. Then I see fresh oil accumulate in the front circuit. I don't know if its slosh from cornering or the fact that its a closed circuit instead of vta, but unlike what Tom claims I do see quite a bit of oil accumulate here under extended high boost conditions.

 

No, you need the vacuum from the intake manifold when you're off the throttle and the turbo isn't making any vacuum in the intake pipe.

 

I failed to mention that I already have stm -6 fittings in my valve cover. I don't use -an hose, but have -6 to 3/8 barb fittings threaded onto those. Just didn't want the added expense at the time of an fittings, etc. Also, I'm not running the stock pcv. I have a boomba racing 3/8 inline check valve right off of the intake manifold.

Also, capping the im port, and running both lines to a catch can sounds like it would be better for a drag, or track dedicated car that is constantly under boost.

 

Also, correct me of I'm wrong. I believe the stm can is the best of both worlds. It leaves the im connected so when you're out of boost, the motor is under vacuum, but more importantly, it uses both valve cover ports to evacuate crank case pressure, instead of shutting down the rear port with a check valve, since it is all run to a single can.

 

i recently bought this can as well and i love it. Its worth it!!!!you will feel the difference

 

^ I'd love to see some pictures installed. Were you having problems before you bought this can? Mods?

 

I can attest to feeling the difference as well. My car felt a decent been more snappy once the crank case was breathing properly.

 

I'm starting to think a catch can isn't necessary at least on the front side. I already had a AGP can on the rear pcv connected to the intake manifold. After my last round of mods including a FP Black and big cams. I was planning on installing a catch can setup like the STM one. But because of lack of funding I ran a vacum hose to the turbo intake. I have been constantly checking the intake and after 4 months not a drop of oil from the hose or turbo.

 

Grabbingears-Are you running e85? I don't see a whole lot of oil in either can, although there is some, but definitely enough water that I wouldn't not run a catch can. This was my first full tank of e85, and I have been monitoring the car closely. I'll fill up with 93 this weekend, if it doesn't rain, and see how the car acts. Also, my fp red is journal bearing, so i don't have that oil leak issue.

 

Instead of using the intake for vacuum. Would it be better to use exhaust?

 

Never tried it.

 

I had a mishimoto 3 port can and i had it vented, it would collect water every 2nd day. I ran E85 for a lil while but even when i stopped using E85 it was collecting water. The car was feeling a bit slugish and it felt like it was miss firing. People might think i am crazy for thinking this but as soon as i installed this catch can the car started feeling different [Good] all together, very responsive. i have had this catch can for almost 2 months now and i daily this car, there is barely any oil in the can. My honest opinion would be get a can that would be recirculated instead of a vented one. It does make a difference. I did alot of research before i made my decision there wasnt much info on this particular can. Hopefully this will help you and anyone thats tryna buy this can. Feel free to ask questions

 

What exactly makes the STM can so good to prevent the FP turbos pushing oil?