Alternative to oil catch can?

[AMontgomery]

I'm having a conversation with the service manager (who just happens to build and race 1600hp+ turbo drag cars) about building or installing an oil catch can for all the reasons we already know. His response made me think. He showed me the crank case vents on his drag car. They were basically hoses running from the crank case vent to a catch can with a filter. There was no return line providing any suction back into what little intake he had. His reasoning was that the crank case is already under pressure, especially on a boosted car and that oil vapors would come out on their own.

I'm considering the pros and cons of a similar setup for our cars. Vent hoses to canisters that vent to the atmosphere instead of recycling the vapor back through the air fuel mixture. I know it would be bad from an emissions standpoint, but let's be honest, we really don't care about emissions on these cars unless we live in states with annual inspections. Other than that detail, I can't think of any reason to run a catch can that vents back into the intake.

I would like a few other thoughts on this before I go head first into rigging this up. I may give it a go, and monitor the engine carefully and note any changes. It would certainly be cheaper than buying a $200 prefab catch can.

 

[kjohn09e]

I'm in for this as well. Arkansas doesn't give a damn lol.

 

[CanadianGuy]

There are legal challenges with a VTA system for a street car due to emissions. May want to consider that.

 

[AMontgomery]

The requirements for road legality in this area are basically to run, have an unbroken windshield, and have blinkers. I could see it being a legal issue elsewhere but here it's not a problem.

I'm wondering if there are pitfalls to car reliability with a VTA system. And what factors need to be considered when replacing stock systems. Sensors, PCV, etc.

 

[dave_f]

You shouldn't have any issues as long as you plug up your intake. Although, I don't see how it's going to be beneficial not to recirc the gasses especially since the available bolt on catch can options all have appropriate lines to do so.

My mk1 rabbit currently has a hose off the pcv running to the ground and i've had cars with catch cans that vent to the atmosphere.. It's not ideal lol, definitely smells quite a bit. I wouldn't be able to live with that in the fiesta.

 

[AMontgomery]

Does the PCV have a purpose in a VTA system?

 

[AMontgomery]

And is there a point to having catch cans? Would a filter on the vent accomplish the same thing?

 

[D1JL]

The PCV system was developed to Positively Vent the Crankcase of gasoline vapors.
It was a SAFTY device first, if you have seen an oil pan blow up or valve covers blow of, you would understand.
Vents and a road tube did not work very well.
PCV did not become an emission control device (1st, BTW) until much later when the systems were closed, so now it did two things.

Besides you people are polluting MY atmosphere.


Dave

 

[AMontgomery]

So the extra vacuum from an intake is required to remove pressure from the crank case?

Not sure why it would work in a 1600 hp drag car running 30-35 psi (and has been fine for years) but not in our cars.

 

[D1JL]

I never said anything was required.
I just stated what a PCV system was designed to do.

Besides your topic is an alternative to catch cans.
What is used on a race car that only driven for 15 seconds or less is far from what should be used on a daily driver.
BTW, the FiST already has an oil separator built into it.

I am not trying to argue with you, just trying to help you decide what you want to do.
You said "I'm considering the pros and cons" and "Does the PCV have a purpose in a VTA system?" and "And is there a point to having catch cans? Would a filter on the vent accomplish the same thing?"

I am just providing the information you requested.
I already made my decision.


DONE

 

[AMontgomery]

And again, I like to test information given and get multiple answers from multiple sources then apply logic and come up with one on my own. I'm not trying to be a smart ass just get clarification.

Here's what I've managed to gather so far;

The PCV system was designed as a safety system (I honestly didn't know this, even after being around all manner of turbo cars for the past decade, and I've never personally witnessed a catastrophic failure caused by a buildup of pressure that wasn't related to detonation or overheating of the cooling system)

It's an emission system. I knew this much. And like most emissions systems, they are largely redundant and unnecessary, when looking at the functioning of the vehicle. (Not to mention the prevalence of people to run decatted down pipes which would be WAY worse than a VTA system, but nobody is fussing about that)

I'd like to know more about the requirements of the system.

Is the pressure, from heat, blow-by pressure, and atmospheric changes, not enough to direct vapors out of a valve cover given a path of least resistance?

Does the extra vacuum from the intake need to be present to adequately remove pressure from the system?

Are there any electronic sensors that will throw codes if the system is bypassed?

Any info Is very much appreciated.

 

[WhiteFords]

I would never run a non-pcv equipped motor again.

My engine builder, who builds a lot of pure race motors, recommended a breather hose off each valve cover leading to a vented catch can. He also had me block off the pcv provision in my intake. His reasoning was to completely eliminate the possibility of the engine inhaling its own waste, like the milky stinky residues which we collect in our catch cans. Race cars will also set up a scavenging system in which the exhaust system pulls out vapors.
While my engine is not inhaling its own waste, I am now inhaling its waste. Even with a highly baffled catch can, I get an oil smell in the car, usually worst on startup and decel.

With a pcv system equipped with a catch can, I feel you get the best of both worlds. No oily odors, no junk back into the intake runners, and better for our planet.

 

[WhiteFords]

Here is the best explanation of these systems that I have found. By the way, I have installed the Damond kit and it is awesome.

http://damondmotorsports.com/blogs/damond-blog/53965956-bye-bye-blow-by

 

[tjd_tdi]

From what I've read, having some vacuum on the crank case (in our case from the IM via the PCV) is good for engine longevity and wear. If you want to eliminate the chance for crap getting into the IM, another alternative source of vacuum is the exhaust via a venturi port.

 

[mercdank]

I use a recirculating oil catch can and a crankcase breather.

 

[TyphoonFiST]

They used to use what they call road draft tube for the PCV gasses until the bark eaters said no more and made us route into the a engine to be cleaned up again....IMO it's just a drop of water in the ocean compare to what China and India aren't doing with pollution issues...as my father would say....I'm all about leaving the biggest carbon footprint I won't be here in 50 yrs. Who the F*&k cares? I like the ideas of catch cans for our cars though....since they are direct injection. Has anyone started a cleaning regimen for the intake valves and intake in general ? If so...what do you do? Use chemical wise etc.?

 

[AMontgomery]

The only way I know of to clean the runners and valves is walnut media blasting. Which can be expensive due to the labor and facilities involved.

So another con of the VTA system is oil vapors and odor in the passenger compartment. That would be an issue I wouldn't want to live with.

I guess a big question, is there any oil vapor that passes through a proper catch can? Or do they effectively eliminate fouling of the valves and runners?

 

[mercdank]

Catch can will most definitely have oil vapor pass through it and trap it. My Mishimoto catch can did a great job of catching what I consider to be a substantial amount of oil after about 2400 miles.

 

[kjohn09e]

I never said anything was required.
I just stated what a PCV system was designed to do.

Besides your topic is an alternative to catch cans.
What is used on a race car that only driven for 15 seconds or less is far from what should be used on a daily driver.
BTW, the FiST already has an oil separator built into it.

I am not trying to argue with you, just trying to help you decide what you want to do.
You said "I'm considering the pros and cons" and "Does the PCV have a purpose in a VTA system?" and "And is there a point to having catch cans? Would a filter on the vent accomplish the same thing?"

I am just providing the information you requested.
I already made my decision.


DONE

Out of curiosity. Where does the FiST have an oil separator?

 

[AMontgomery]

I guess to clarify, what I'm asking is, will there still be some oil that isn't caught by the catch can that is then sucked into the intake?