Catch Can - weird (but good) results

[DamnYankee]

Good deal. They're rather helpful irrespective of the engine type.

I would advise in not using the valve breather, and to just stick the pcv hose on the "in" side, and "out" side to where the pcv currently connects.

Also, which engine are you running? May not hurt to check intake for sludge/carbon and clean the crap out of it. My old upper looked ok, but when I pulled the lower, it has at least 1/8-1/4" of soot and sludge caked onto it, with two injectors at least partially blocked.

Also interesting to note, even running Mobil one with zddp additive like I do now, I still get synthetic oil sludge in the thing.

Who knows...

Ok. I'll omit the breather.
My engine is the 2.9. Is it difficult to remove the intake on it? I've not had to do that on this one.

 

[Paulos]

I'll omit the breather

I think you want to keep the breather the way it is, so it pulls fresh air into the engine. The catch can would simply go between the PCV valve and where the PCV valve hose connects to the throttle body (if I correctly understand what PetroleumJunkie412 is saying). But maybe I'm misunderstanding "omit" in this case .

 

[Nez'sRanger]

I think you want to keep the breather the way it is, so it pulls fresh air into the engine. The catch can would simply go between the PCV valve and where the PCV valve hose connects to the throttle body (if I correctly understand what PetroleumJunkie412 is saying). But maybe I'm misunderstanding "omit" in this case .

The catch can comes with a small cone filter/breather. It's an option that lets the now oil free air into the atmosphere and not into the vacuum line on the plenum. I think we run into emissions problems if it vents directly into the air... Well, at least I do in California.

 

[Paulos]

The catch can comes with a small cone filter/breather. It's an option that lets the now oil free air into the atmosphere and not into the vacuum line on the plenum. I think we run into emissions problems if it vents directly into the air... Well, at least I do in California.

I like the idea of not re-introducing the oil-free air back into the engine, but the PCV valve works with vacuum. Unless you delete the PCV valve (which would make the breather useless), and then you would be venting blow-by gases through the catch can and into the atmosphere (just like the old days ). If you were to do that, you might as well run hoses from both valve covers to the catch can, so there would be no chance of gases building up in the drivers side valve cover. But I'm not sure if it would be a good thing to stop fresh air from circulating through the crankcase .

 

[Dirtman]

Mine has the option for a breather or a just a block off plug (I use the plug because I'm not brain damaged). For the life of me I can't understand the point of the breather either. It makes zero sense to have a catch can if your just venting to the outside air anyway. The catch can is designed to work with the factory pcv system which already has a fresh air side, and this air is metered. The catch can should just be inline between the pcv valve and intake manifold, and sealed air tight.

 

[Paulos]

It makes zero sense to have a catch can if your just venting to the outside air anyway

Well, the catch can in that scenario would keep the oil in the blow-by gases from going straight onto the ground (or the engine compartment) .

Thinking about it, with the PCV system working correctly, everything under the drivers side valve cover should be cleaner than the passenger side, right? Fresh air in the drivers side valve cover, through the crankcase, and out the passenger side with the blow-by through the PCV valve.

 

[Dirtman]

With no vacuum source, crankcase air isn't being actively sucked out of the engine and into the catch can so it wouldn't do anything that a regular old fashion breather cap could.

And if you use a breather cap on the catch can with the pcv system as it should be. All you've done is create a vacuum leak...

 

[Bgunner]

Is it necessary to add the SS scrubber in to the catch can? Isn't the catch can designed to, well, catch the oil?

Actively considering this for my 3.0 for many reasons but mainly the stumbling at idle. I do have the shmeg in the intake and cleaned a lot of it out when I purchased it so I'm thinking this wouldn't hurt my 150k motor to give it oil free air at this point.

 

[Paulos]

With no vacuum source, crankcase air isn't being actively sucked out of the engine and into the catch can so it wouldn't do anything that a regular old fashion breather cap could.

And if you use a breather cap on the catch can with the pcv system as it should be. All you've done is create a vacuum leak...

I agree. Without the PCV system operating, only the blow-by would be escaping into the catch can. And if you removed the breather and PCV you would have to plug the PCV port at the throttle body. In the end, I think PetroleumJunkie412 has it right, with the catch can spliced into the PCV hose between the PCV valve and the throttle body PCV port, with the breather intact.

 

[Dirtman]

This was the best diagram I could find on how a catch can should work. It should be installed as a sealed part of the system, under vacuum from the pcv side. I've seen people use 2, one on the fresh air side but this makes zero sense because that is incoming fresh air, theres nothing to catch... but the main point is, it's a closed system. Introducing any kind of breather in the mix creates a vacuum leak. The air through the catch can, and the pcv must be metered by the maf sensor.

 

[PetroleumJunkie412]

So, by breather I mean the air filter I have on my valve cover. My ECM allows me to adjust my idle, so it works for me. Won't work with a factory ECM unless you make the IAC adjustable.

I also do not use a MAF, so ??‍

Theoretically you want fresh air in one side, vacuum on the other.

Stainless pot scrubber is for surface area. Major improvement when used.

 

[Dirtman]

You also have a map sensor not a maf so the air is metered at the manifold not the air filter. Makes it a bit different. And god only knows what's going on with your squirting thing.

 

[PetroleumJunkie412]

And god only knows what's going on with your squirting thing.

Lol.

A Megasquirt is just a ecm that's damn near universally adaptable to anything with injectors OR computer controlled spark advance, or both.

It's basically just a microprocessor with a ton of sensor inputs and outputs. The program I trolled you into downloading (tunerstudio) is the programming tool.

Depending on which one you use (there's essentially four models), it allows for different levels of control and precision. The only difference between the MS 1, 2, and 3 is the daughter board (processor and some other stuff) that runs the whole shabang.

MS1 was developed to run fuel only, but can be ad-hoc programmed and rebuilt to run ignition advance as well. Very basic, and generally discontinued.

MS2 is a basic system that was designed to run fuel and spark, as is Microsquirt (what I sort of run, mine is a hybrid between a Microsquirt and a Megasquirt 2). Much more advanced than MS1; perfect for most street and track applications.

Microsquirt is sort of its own thing, but uses Megasquirt 2 software and firmware. Generally it was designed to be a low cost option that doesn't require soldering boards together like a megasquirt. Unless it's a hybrid. Then it requires a ****ton of board work like mine did. Advantage of a hybrid (mine is a DIYPNP1.5) is full megasquirt 2 functionality with a lot of ECM controlled relays for stuff like boost control, nitrous, cooling systems, etc. A good example of use for the relays is when I wired and programmed my water/methanol jet. Wired in a amazon 12v diaphragm pump and programmed the relay so that the pump kicks on at TPS > 69% and RPM > 2269. Took less than 10 keystrokes, and no.f*cking around with sh*t like pedal switches.

Biggest advantage of DIYPNP kits are that they have adapter headers to plug directly into a factory harness without cutting, so that you preserve your harness. Also allows your ECM to be switched between vehicles with an adapter change. Or just have all your vehicles on the same harness connection and effing send it.

Megasquirt 3 and Gold Box are really advanced units with high amounts of precision and an almost disgusting level of control. Applications are typically narrower though, but they can still be applied to any engine. Only reason to go to a MS3 or gold box is serious competition, or to avoid most of the electronics work by buying a prefab unit for your specific application with a base tune already written on it. Common prefabs are usually for things like Turbo Miata, Ford 4.6 and Ford 5.0.

Megasquirt / Microsquirt are usually a pretty easy thing to build and use. Forums for it are supportive, and there is a TON of info available for anything ranging from a Briggs and Stratton RaptorIV all the way to Jaguar V12s.

The only time they're difficult to use is when there's no info out there to utilize with your engine or engine family. Like my build - there was absolutely nothing out there on Ford Cologne. So deathbypsi and a few others lent a lot of help, and I posted my programming here for anyone else that may come along to use.

They're seriously worth looking into to using, even for a bone stock daily driver. The level of diagnostics they offer is logarithmically superior to OBDII, plus the analysis software (MegaLog Viewer) allows you to tweak your tune to absolute perfection. Also they will let you tweak your engine for fuel economy, power, etc. I know I posted somewhere on here how simple it was to change injector sizes, but if memory serves it was seven mouse clicks (including opening the software) and three keystrokes. Try that with a factory ecm.

Even for a beater, it makes financial sense. Of, your super hard to find oddball injector size is hard to find? Slap any old injector in there and punch in the new lb/hr value. Send it.

Your super old, super rare engine needs a carburetor that you can't find? Whatever. Machine a GM TBI injector adapter plate for your intake, slap a few low impedance GM injectors on there and give 'er a full send.


Hands down most powerful piece of aftermarket automotive tech I've ever put my hands on. They completely change the way you look at an engine; it's like using a high performance carb on an efi engine, but it doesn't suck like a carb does.

Anything else EFI I ever touch will have one on it. I'm just patiently waiting until they finish the GDI driver boards so I can build one for my Challenger.

 

[Josh B]

I wish I could have found an aluminum one before I shoved a stainless one in there. The thought of one if those stainless ribbons getting pulled through the engine scares the crap out of me.

Thought about using a copper one, but didn't want to find out the hard way if crank case gasses would react poorly with it, and send some sort of gaseous death into my intake.

What do you think about a brass one?


I once learned a trick on carbureted engines to put a screen under the carburetor, cupped down into the intake, to help it vaporize and mix the gasoline and air better.

I just used a piece of galvanized window screen wire in mine. Not sure how long it took, but later when I pulled the carburetor that screen wire was nearly all gone.

I then tried a piece of brass screen and it never did fail