I installed a Mighty Mouse catch can, and set it up according to instructions as well as by looking at a few installs on here. It's not working like I'd expected. Nothing wrong with the can at all, but I think my engine needs a different set up and/or component change. I've already bought a few parts, I just wanted to know if I have the right idea and if I should be concerned about a couple of things.

Right now, I have a -10 line plumbed to my passenger side valve cover going to the inlet of the catch can. The outlet goes to the PCV port behind the TB. Driver's side has a breather vent mounted at the front. This is supposed to be for fresh air. Both the passenger and driver side covers have baffled AN fittings installed. The problem I'm having is, the driver's side breather is misting the engine bay with oil under load. I was worried this was going to occur, but I figured the catch can would have enough flow from one side to keep it from happening. I see a lot of people with turbo cars running BOTH valve covers to the can, so I'm guessing this is just a must have. I still need a fresh air source in, and these Summit Racing valve covers have baffled PCV ports up top, so I'm going to run a line from one of the ports to my air filter pre-turbo.

Is there any issue with setting it up this way? I can't see there being one, but it never hurts to ask. My biggest concern is that oil is still going to get into the PCV line from the valve cover and get sucked into the inlet of my turbo. Is there any way to mitigate this from occurring? Will having BOTH covers plumbed to the catch can prevent it? I just want to keep my freshly detailed engine bay looking good and not set up the can in a way that could hurt my new engine.

 

Contact David @ MM and ask????

 

Already did, he said to check the inlet for obstructions ( there aren't any ) and for pics of the setup. I wanted some opinions from people who have set these up on their cars, just to see if I'm on the right track.

 

Crankcase ventilation can be VERY simple, if you let it.
On a modern,tight- naturally aspirated engine, a simple PCV valve to manifold vacuum and filtered make up air from opposite rocker cover works well enough for the first several hundred thousand miles- normally no problem.
.
For anyone running MANIFOLD PRESSURE, there is this one neat trick:
... Obtain 6 feet of 1/2" id heater hose, stuff one end in where the PCV valve "used to be".
Cap the open manifold port, and than secure the far end of the six foot Crankcase VENTILATION hose somewhere back along frame rail. This is called a " Road Draft Tube" worked just fine for 70 years ago, and it still works the same way.
. The other side of the engine, run about 18" of 3/8 hose to a cheap Xhinese "breather/filter" and secure it over near your main air intake filter- it won't bother you much.

 

I used a -12AN line for your -10AN line and used a section of 3/8" hose to run the fresh air filter into the fender.
Running it into the turbo inlet will put that mist onto the compressor wheel which I'm not a fan of.
I'd up the size of the -10AN line to -12AN and move the fresh air filter to another location.
Make sure the port your using on your valve cover has a baffle too.
I had mine setup this way on an SBE LS1 at 700whp for years with no issues.

 

So, I ended up running another -10 line from the driver's side to the catch can, and used a piece of hose connected to the PCV fitting on the driver's side and routed down under my car and zip tied to a bracket on my trans. At the end of the hose is an inline PCV valve that allows no pressure out, but allows airflow in through the breather at the end. So far so good, and my engine bay is staying clean.

 

Put a small filter on the end of that line, you don't want it pulling in dirty unfiltered air into the engine.
Something like this.
Spectre 3998 Chrome Clamp-On Crankcase Breather Element Filter - 3/8" - 1/2" | eBay

 

I have one, lol. See where it says breather at the end? I definitely would NOT be wanting to be pulling dirty air in, made sure to have that point covered.

 

I'm running dual -10s, one from each valve cover into a dual inlet can.

 

pressure out...where? Out of the engine? You want to let the crank case pressure out, otherwise it'll find its way out elsewhere...like seals. You don't need airflow IN to the crankcase, just out.

 

I'm a little confused by this too and am wondering what kind of can you're running.
If it's just a vented can then a -10 off each valve cover is more than sufficient, this is my current setup.
If it's a PCV style can, then the idea is to draw fresh air through the engine crankcase.
There should be a large line (-10/-12AN) running from the engine to the can (pressure vent), a vacuum source with a check valve running from the intake to the can and then a filtered air source for air to be drawn into the engine crankcase.
The driver side line should be the one with a filter running outside the engine bay that way when the crank case is under vacuum, its drawing air from the driver side inlet, through the crankcase, into the catch can and into the intake.
While under pressure, the majority of the pressure is released via the -10AN line through the catch can and a little through the driver side.
If I understand what you're saying, the line off the PCV valve going under the car does nothing.

 

What do you think the dual -10 lines out of the covers going to the catch can are for? That's to relieve crankcase pressure. The line going under the car is for fresh air in, as the Mighty Mouse can has an internal PCV. I guess I need to post pics tomorrow as my explanation is confusing, I guess?

To reiterate: I had a single -10 line from my passenger side cover to the can, and a smaller line going back to the intake from the outlet ( PCV ) on the can. The driver's side had a breather filter to let fresh air in. Unfortunately, it was allowing an oil mist out under boost/RPM. I suppose I could have just fit the cover with a one way check valve, but I instead ran a second line to the can from the driver's side. The system STILL needed a fresh air inlet, which is why I used the PCV fitting on the back of the driver's side valve cover and ran a line under the car with a PCV at the end and the aforementioned breather filter attached to that. If there's pressure in the crankcase, I want it going into the can, not into the line under the car. The line needs to be one way, into the engine.

 

hey podna, go read what you wrote. I put it in bold. You didn’t say “let the pressure out”, you said “ PCV valve that allows no pressure out” Which is NOT what you want. Maybe you wrote it wrong, but you wrote it and I thought clarification was needed.

 

There are two PCV valves in this set up. One in the catch can, and one in the fresh air line. The pressure goes into the can when under load through the -10 lines. The return line from the intake to the catch can does not allow boost to enter the catch can by design. I did not want the fresh air line to be a route for crankcase vapor to leave the engine, so I put an inline PCV valve in to block the airflow out of the breather. Doing this was suggested by Mighty Mouse ( David had suggested putting a one way check valve underneath the breather on the valve cover, this is basically the same thing, only the breather is now mounted remotely. ). Look at the install instructions here: https://docs.google.com/document/d/1...U3skHweAQ/edit Literally the only changes I have made to what is shown are to have lines from both valve covers, and the PCV valve is at the end of the remote hose instead of in the valve cover ( I don't have stock covers ) and the line has a breather at the end instead of going into the turbo air filter.

I'm confused as to why this is seemingly not a good set up. It's a slightly modified version of the standard Mighty Mouse instructions, which I'm assuming have been used by many others with no problems. @MIGHTYMOUSE , can you chime in here so future readers can have a definitive answer as to whether I have this set up in a functional way? Here are pics of my engine bay, don't have a pic of the line under the car though: