Do You Use A Catch Can?

[Silvercreek]

Hello to all,

I've been around for a while and have some decent basic automotive knowledge. I've lost track of the performance world of car and pickups when it come to the more modern engine technology and the modifications some folks are doing on their trucks, IE; late model Dodge RAM 5.7L Hemi.

Does anyone know if there is a technical or valid reason for having a catch can. This is an aftermarket container that goes between the crankcase ventilation (PCV) and the intake manifold. The only thing I can get from the guys that are using these CATCH CANS is that it keeps the throttle body and intake clean of excessive oil that comes from the crankcase ventilation. After a few thousand miles the bottom portion of the catch can is removed and emptied of a few ounces of oil that would otherwise be sucked into the intake. Part of it getting burnt with fuel combustion with some residue on the inside of the intake manifold and throttle body.

So far I have labeled it, "Just Another Gimmick." What say you?

http://billettechnology.com/bt/videos/catch-can-standard-installation/

 

[Johnny248]

I have a catch can on my Hemi Ram, and it does catch a TON of oil for what it is. I would think that it does for sure keep the intake manifold and intake valve clean. I don't know how detrimental that oil vapor is to such items, but people also claim that at least in the Hemi applications, it reduces spark knock caused from the oil in the combustion chamber.

I also have one of my daily driver car, and again it does do a good job of collecting oil.

Gimmick??? I wouldn't call it that. I think that it prob serves some benefit. BMW actually uses them as part of their PCV system on their vehicles. That being said, there millions of vehicles driving around with out them. So..... I think it is just like anything else. Do you NEED it ? not really. Is it a nice thing to have? Sure, I believe so. Do you NEED to use high end oils, filters, tires, replacement parts, etc? Of course not. Does it hurt? Not at all. Does it provide peace of mind? Indeed.

 

[SHOZ]

Here's what I drained out of mine after 2500 miles. It's mostly water, gas and a little oil.

Turns into hard brittle carbon with enough heat.

Here is one port that gets fuel spray and the other that doesn't.

 

[IndyIan]

If its needed or not depends on the engine and how its used.
Running near redline with hard cornering can cause some motors to suck alot of oil through the PCV system.
At one autocross, the course layout had my Neon near the rev limiter for quite a while and then had a long right corner, which caused quite the smoke show. Never had that problem before or since, but that day I needed a catch can.

 

[SteveSRT8]

New gen 5.7's already have an oil separator built into the valve cover. LOTS of other makes do also.

Funny that at two major large Hemi shootout drag meets my car beat anything stock or even near stock with a 6.1 or a 5.7 despite my not having one. While the allegation of excessive KR is a real one it has never been an issue here after 8 years of flogging the 6.1 all over the country.

But for the average driver they remain a 'feel good' mod like longer filters and boutique oils. Certainly won't hurt much unless improperly installed.

 

[ARCOgraphite]

On a port injected engine PCV oil would only aid in top oiling of intake valve stem and seat. If the car is ingesting an inordinate qty of oil through the PCV, then there is a PCV design issue and a oil mist separator my be warranted. My 2007 4.3 chevy truck and my 05 Suzuki Aerio SX were oil eaters. The Chevy didn't have a PCV pill - just a large open orifice to the VC and the oil got all over the flakey VORTEC multiport injection system inside the nylon manifold.

 

[Jeffs2006EvoIX]

I personally think it's all hype in a DD application. In racing maybe it had is place.

The water and oil you see does not prove your engine sees that. That is what the PVC is for. It's designed to deal with that.

Then look at emissions. Pull up to a station hear in CA with a catch can and guess what? FAIL.

Why is that? If a catch can is so great?

Racing? Where emissions and crazy driving conditions maybe there isa place. In most folks cars or trucks?

Nah

 

[SHOZ]

They aren't needed I guess until the valve stem carbons up and sticks. Then this could happen.

 

[d00df00d]

My car comes stock with a cyclonic separator.

 

[OVERKILL]

Originally Posted By: d00df00d
My car comes stock with a cyclonic separator.


Yup, BMW has been using those for quite a while!

 

[kkreit01]

Everyone on the Ram forums seem to think it's a "must-have", "first mod", etc. I've seen the pics of gunk collected within 1000 miles. I've also seen the dirty TB pics. I finally caved and ordered one during BT's annual 40% off sale. I couldn't see spending $130+shipping on one, but at 40% off, I grabbed it. They were popular on 2nd gen Neons as well. Maybe it's a 'Mopar thing' -- like the 30K copper plugs?

 

[Voltmaster]

I am not an expert but I doubt any car below 50k has a reason for this.

As others said Cyclonic separator is only thing closes to a catch can.

Same way 3k oil changes are old ways of thinking, i would imagine catch cans also would be. Well maintained car doesnt need any of these things.

 

[Jeffs2006EvoIX]

Originally Posted By: SHOZ
They aren't needed I guess until the valve stem carbons up and sticks. Then this could happen.

There has been no evidence on the VW DI crowd that reflects a oil catch can helping at all.

The valves carbon up just the same. Only thing that helps intake valve deposits thus far is WMI (water/meth injection).

So yeah these things don't work at least in a DD DI application.

 

[Jeffs2006EvoIX]

VW has a similar part like BMW cyclone. It's a 2 phase oil separator. It's all tied into the PCV system. Is why is best to leave it alone.

 

[Johnny248]

Originally Posted By: SteveSRT8
New gen 5.7's already have an oil separator built into the valve cover. LOTS of other makes do also.

Funny that at two major large Hemi shootout drag meets my car beat anything stock or even near stock with a 6.1 or a 5.7 despite my not having one. While the allegation of excessive KR is a real one it has never been an issue here after 8 years of flogging the 6.1 all over the country.

But for the average driver they remain a 'feel good' mod like longer filters and boutique oils. Certainly won't hurt much unless improperly installed.



My '11 Hemi still collects quite a bit of oil in the catch can. If there is a seperator built into the valve cover, it doesn't do a great job. That being said, on my Ram I have one of those BT Style cans, and on my car I installed a air line water seperator. The RAM catches what seems to be mainly oil. In the car, I see a layer of water/moisture with a layer of oil sitting on top. I don't know if the difference in "catchings" is engine design or catch can design. I just notice that I don't really see any sign of water in the Ram's catch can.

 

[Johnny248]

Originally Posted By: kkreit01
Everyone on the Ram forums seem to think it's a "must-have", "first mod", etc. I've seen the pics of gunk collected within 1000 miles. I've also seen the dirty TB pics. I finally caved and ordered one during BT's annual 40% off sale. I couldn't see spending $130+shipping on one, but at 40% off, I grabbed it. They were popular on 2nd gen Neons as well. Maybe it's a 'Mopar thing' -- like the 30K copper plugs?

I have the Bullys Performance BT Looking style can on mine. Same thing, very expensive. I bought mine used on eBay for $50. Couldn't see spending $130 on one of these. And as you said, mine collects a pretty good amount of oil in it.

 

[SteveSRT8]

Originally Posted By: OVERKILL
Originally Posted By: d00df00d
My car comes stock with a cyclonic separator.


Yup, BMW has been using those for quite a while!


Fancy name for a baffled separator, first seen by me on a Chrysler K car! Hardly a BMW exclusive!

 

[JHZR2]

Originally Posted By: OVERKILL
Originally Posted By: d00df00d
My car comes stock with a cyclonic separator.


Yup, BMW has been using those for quite a while!


My 81 and 82 MB diesels had those! And probably many before that.

IMO, the question is generally if there is a value to the UCL from the oily and wet blowby gasses. Sure, they may get in and do funny things combustion-wise, and thats a different story, as most people, for most applications, arent running their engines THAT hard that it matters. But it may in terms of longevity.

Obviously the water and fuel doesnt seem to have an effect on the oil based upon the UOAs we typically see. But does it have an effect on compression or wear rates in the UC area?

 

[OVERKILL]

Originally Posted By: SteveSRT8
Originally Posted By: OVERKILL
Originally Posted By: d00df00d
My car comes stock with a cyclonic separator.


Yup, BMW has been using those for quite a while!


Fancy name for a baffled separator, first seen by me on a Chrysler K car! Hardly a BMW exclusive!


Cyclonic separator!

Are we thinking of the same thing?

The crankcase gases come in the lower vent, are spun around inside, dropping out the oil with the air exiting through the centre tube and the oil flowing out the bottom back into the pan.

I don't recall seeing one that looked like that on a K-car

 

[SteveSRT8]

Originally Posted By: OVERKILL
Originally Posted By: SteveSRT8
Originally Posted By: OVERKILL
Originally Posted By: d00df00d
My car comes stock with a cyclonic separator.


Yup, BMW has been using those for quite a while!


Fancy name for a baffled separator, first seen by me on a Chrysler K car! Hardly a BMW exclusive!


Cyclonic separator!

Are we thinking of the same thing?


The crankcase gases come in the lower vent, are spun around inside, dropping out the oil with the air exiting through the centre tube and the oil flowing out the bottom back into the pan.

I don't recall seeing one that looked like that on a K-car

No, we are not thinking the same thing. But the Dyson people are going to sue!

My point was that having a separator in place to assist in oil recovery is nothing new or exclusive to any particular car mfgr. Frankly, if my engine had the serious amounts alluded to here I would want to see if there was a mechanical problem!