Lets Talk About Crankcase Pressure and Catch Cans!
 

Lets talk about some ways to get rid of excess crankcase pressure and ways to set up catch cans etc. Whos currently running a catch can system? How is your PCV system set up? Where do you vent the extra pressure and gases to? Do you use breather filters, a breather on the oil cap, anyone using a Venturi Style setup to the exhaust, check valves... etc etc etc.

My eventual setup will consist of:

PCV valve on valve cover to Catch Can (CC)to Throttle Body (this is how the factory system is set up minus the CC) and then the drivers side valve cover port will be linked up to a catch can and then either be routed to atmosphere with a filter or port to CC to exhaust using the venturi method. The idea of this is to be able to pull an appropriate amount of vaccum from the crankcase to remove any excess gas/oil etc from the crankcase and allow it to be replaced with good clean fresh air while at the same time filtering out any oil or blowby. My car requires a constant vaccum to perform at it's best.

Discuss. I'm particular interested in turbocharged/supercharged applications.

I'm hoping to get some gurus in here that are experienced in these sort of things and may be interested in doing some experimentation for this. I'd happily donate my car and dp to play with the exhaust style venturi method for this. It'll require some welding, some testing using a vaccum gauge to determine how much vaccum this method is pulling... too much and it'll start to pull oil away from where it's most needed. If it turns out to be an appropriate level of vaccum then I'll be hooking it up with a 1 way check valve and a catch can and dumping extra gases out the exhaust. I understand this may not be actually legal, but my stock exhaust isn't legal anyway so w(who)tf cares anymore. this will be on my catless dp setup that i will eventually be adding a cat to.

My friend has a catch can in between valve cover and the vacuum port in the throttle body which is the stock setup in the Yamaha V6 SHO motor. He has installed a Vortech in his motor. I have seen vacuum pumps installed on SBC and SBF used to create a vacuum in the crankcase and vented into the air.

Bob

^^^this is how step 1 of my setup will be

If you have excessive crankcase pressure, in my experience it has always been the result of a leaky intake on a boosted motor. Boost blowing into the crankcase.

Otherwise you have a ring seal problem. Which your motor doesn't have.



I would run a hose from your air intake, to a catch can, and then to the valve cover.

I agree with Enkie. I've seen Supras with wiggin's clamps on the Radiator hoses because they are pressurizing the block. Is the car burning oil? They make oil catch cans that have moisture (oil) separators that can work well for for this. By the way the supra with the wiggins clamp was totaled when that thing let loose and leaked radiator fluid on the rears.

^^^ no issues with my car currently that aren't already figured out (I am burning oil but it's soon to be fixed, figured out the issue a bit ago but haven't had the time to fix it yet... busy week for me.) :) just a topic that i'd like to keep open for discussion. (there is a large and busy thread on my other forum about this and i'd like to hear your theories and ideas on it)

Like I said, I'll be running a catch can between the pcv valve and the throttle body vacuum nipple, and then an additional system between the valve cover and either the intake or the exhaust.

I'm familiar with catching oil and different ways to do it... just want to look mostly at ways to help get rid of the extra gases and oil specifically using the venturi method with the exhaust system mentioned above.

Enkei, can you clarify your leaking intake comment above? I'm not sure I'm quite following you. Are you referring to the intake valves in the head, or the intake manifold, or the intake piping to the turbo... lets be specific :) I'm imagining your referring to the intake valves but I could be wrong.

I may have a problem with my piston rings as well as a matter of fact, I've got low compression right now, and I'm going to need to do another compression test to confirm if solved or not.

Well here are my $0.02.

1) I like the addition of before the TB. It is always best to keep oil and fluids out of the intake track. LS motors have this problem and we use CC with oil separators. THey go for ~$70.

2) Venturi setup: These are use a lot of ship's to draw a vacuum on our main condensers (steam) We run steam through the Venturi and draw a strong vacuum that removes non-condensable gasses from the condenser. I would say if you are going to experiment with this install a differential pressure gage to measure the delta between across the venturi and a pressure gage upstream of the venturi to measure the pressure build up between it and the turbo. The DP cell will indicate the motive force for the venturi. The upstream pressure gage will indicate the cost you are paying for having the venturi in since you will have least potential across the turbine wheel. Finally I would find something prevent it from sucking up oil. Like weld in a baffle close to the suction. Every ejection pump (it's the laymans term for what you want to install) has a strong suction it would be possible (with a good venturi) to suck the oil pan dry VERY quickly. SUrface ships actually use them for dewatering flooded spaces.

NOW we're talking!!!

CC = Ebay, 30 bucks shipped 750ml whoot!!!

Ok onto the important stuff... I happen to know that there are at least 1 or 2 srts and multiple other race cars (race not street cars) that are running a venturi setup to the exhaust. Don't have a way to contact them though.

here you mentioned: can you clarify this for me? are you suggesting a power loss by using this system? I'm really wanting to try this, maybe hook up a vacuum gauge to my DP (have an extra bung I can use actually) and see how much it's pulling. If its in a good range i'd like to give it a shot and see whats up. it'll be valve cover to CC to check Valve to exhaust.