On another thread someone mentioned that when using the Campbell Hausfeld filter you should reverse the direction of flow. By this I assume he meant that the arrow should point toward the PCV valve rather than with the flow toward the intake. By doing this he thinks the oil vapor coming from the PCV valve first goes through the center filter, and then after the oil is seperated out, the air goes out the side passage without drawing the air through the oil soaked center filter.

Well this sounds like a good idea, but it goes against what I understand about these vapor seperators. It is my understanding that they work by spinning the incoming flow against the sides of the "can" and the seperated fluid then runs down and collects in the bottom. This is what most effectively seperates the oil/water from the air in the vapor. This is why the flow direction is indicated on any type "catch can" as well as this Campbell Hausfeld filter.

Am I correct? Those of you who have done this mod, which way do you have the arrow pointing??

 

I thought lots of you have done this mod???

 

It's probably me you are referring to. Do it as you please. But if you look at the fact that these small separators were not designed for a hot oily vapor, you need to modify it's setup. On an air compressor you have pressurized air with H2O that will come out of suspension as it decompresses and cools, because the filter will also stop particulate matter in the bowl area, neither of which is a factor on your car.

You want the vapor to pass thru the filter first to wick out the oil. Then with continued vacuum draw the oil will drip down and not continue back into the intake line. Without the filter it will only act like an enlargement of the line. Vacuum is ~equivalent to half that amount in PSI. so 20 inHg of vacuum is close to 10 PSI . This is adequet to pull thru the filter. The reverse is true. If oil saturates the filter, a strong draw will draw the liquid oil right back into the line where you don't want it to go.
correct:

incorrect:

What you'll find by doing it the other way is limited collection of oil as it is not being stopped effectively. Or better yet, try it both ways for 1000 miles each way and meassure the volume of oil collected and report back with your results.

 

I have read on the forum that the element that comes with the housing is actually too restrictive and will decrease HP, this is based on what others have found and posted...

What i did was, took the element off and just went to pepboys and got some of the pcv filter material and stuffed it into the housing and up twards the inlet, this way the oil is captured by the filter and runs down the bottle to the bottom.

i am not capturing "Lots" of oil, but i am not sure if my car is blowing "lots" by either?

 

Well I have done a search on this and about three other forums and nowhere have I read that anyone thought the housing is too restrictive -- though some do think the filter should be removed.

To reverse the flow, or fill the bowl with filter material indicates a lack of understanding as to how this and most other "catch cans" work. It is the spinning of the vapor against the sides -- the centrifugal action -- that seperates the oil/water from the vapor. If you remove the bowl of the Campbell Hausfeld filter you can see that there is a round piece of plastic held in place by the white filter assembly. This piece of plastic has screw-like threads on the outside that fit closely against the bowl and that channel and spin the incoming vapor against the sides of the bowl. It is this centrifugal action that most effectively seperates the oil/water from the air in the vapor, though any type of filter media will also seperate out SOME oil/water. If you are concerned about the filter getting saturated with oil and then being sucked back into the line, just remove the filter -- it is not necessary for this application. What you want is unimpeded centrifugal action.

After doing a search and reading the posts about this mod I posted this thread hoping to get more info -- but, oh well!! On another thread someone mentioned to be sure to get the C/H filter with the glass bowl. Well after talking to tech at C/H they insist they don't make this filter with a glass bowl! (Though they do have a larger version with a metal bowl.) Anyway, lots of misinformation on these forums, so be careful!

Though I want to add that there is much more great/accurate and valuable info, and I would be the first to admit I have learned a lot from these forums!

 

1g1yy,

Can I ask you something? Would a centrifugal separator remove smoke from air or would a filter element work better? You are comparing apples and oranges. But if your mind is made up already and all the info you have seen on other sites is wrong as well, why did you post the question?

An air compressor is pushing air at 90 psi, you are sucking only 10 psi max. You won't have the same volume or velocity of air flow moving around the bowl. It needs better filtration to remove oil from the crankcase vapor. In fact it was not meant to remove vaporized water from the air flow but water droplets from the air so as not to effect paint applications. Some folks like using stainless steel wool to filter thru and others have different ideas. But you need a filter element of some type for the oil to adhere to and drop free in the bowl. That's why the Greddy is not adequet IMHO. Also remember that the 4 cylinder engines that Greddy is designed for barely pull vacuum, certainly not like a V8. So a filter element may be restrictive in that application.

Sorry I could not convince you.
Cheers

 

Sorry, but all this is YOUR fault!! You see, a couple days ago when I decided to do this mod I did searches for info. Well I would have been content to simply install the C/H filter as a couple threads directed -- but NO, I had to come across a thread where you said to reverse the flow direction! So I started thinking about it and posted this and a couple more threads to see what others had done. Well now I'm thankful for your post because it confused me enough to where I felt I needed to do a little research and thinking about how these work. So my initial post is pre-research/thinking, my subsequent replies are post-research/thinking!

Anyway I believe it is you who is comparing apples and oranges when equating smoke with a fluid held in suspension in air. Vaporized water/oil IS droplets of each fluid held in suspension in the air. Larger droplets can certainly be filtered out with a filter media -- but tiny droplets are most effectively removed by centifugal action.

Anyway, thanks for getting me thinking -- and I'm afraid we will have to agree to disagree on this!

 

BUT.............does it slow the car down ?

 

Why would it??? This only draws vacuum on the crank case. Unless you have terrible blow-by it works fine. Remember, when you are accellerating you have no vacuum and if you are boosted it shuts off quicker. You only have significant vacuum when idleing, cruising and decellerating. So no. It would not slow your car down. with or without a filter.

 

there were some posts awhile back that the car lost a couple of tenths in the quarter, so roll your eyes another direction

 

It had nothing to do with the driver? You should have seen my times. It must have been the filter. Yea, that's the ticket.

I was hoping for dyno comparison.

 

If you really want to do it right I would recommend the AMW catch can, hands down best air/oil separator out there.

 

With you, and would like to add the C/H filter is really not large enough for the job.
I couldn't find a filter the size I wanted, they were to big or to small so I made my own catch can from an automatic oiler.
The inlet is a pipe that goes 2/3 the way to the bottom of the can and I inserted a peice of PCV filter media at the top it traps the oil in the lower section of the can quite well. $40.00 vs $100.00+ for a Gready catch can.

 

Let's look at this a minute. If only a vacuum were applied, no flow would occur and no oil would end up in the intakes. Well, oil is collecting in the intakes, so there must be flow. Where does the flow originate? Air is drawn out of the throttle body housing, through the engine and PCV and then back into the intake. Does the air go across the MAF and get calculated by the PCM? No, it goes into the intake after the throttle body so vacuum is applied (vacuum being found downstream of the throttle plate). So, if the engine is designed to draw air through the crankcase and into the intake, it must be programmed into the PCM to correct for it based on a number of things like throttle position, RPM, speed, etc. Now, if this flow is restricted, as would be the case for a filter designed for, say 6 ACFM at 90 psig pressure difference used at @ 10 psig pressure difference, then the car would run richer and the PCM would have to adjust accordingly. Any type of filter is going to change resistance over time. This means the PCM has to deal with another variable. I'd think $88 spent on a catch can is well worth it. Check out www.accmachtech.com

As for the centrifugal effect versus the filter effect, the reason there's centrifugal action prior to entering the filter is to remove the larger droplets from the airstream first, reducing collection on the filter and minimizing the subsequent increase in pressure drop across the filter and the resultant decrease in flow. The filter is there to catch the small droplets that don't spin out from the centrifugal action. The vapor will pass through unless it cools enough to condense or the molecules impinge upon the filter/collected fluid with enough force to mix with other molecules to eventually form oil drops.

You can increase the efficiency of any catch can by keeping it cool since more combustion products will condense out.
Retention time within the catch can is important, also; the larger the can and the greater the surface area within the can for the vapor to travel across, the better (i.e. mesh/filter material creates large surface area).

Since the vaporization temperature of oil is high, any well designed catch can should work as long as it can meet the flow requirements and the flow remains consistent over time.
The catch can linked above is a compromise for me. Less expensive, smaller, but probably not as effective as the Greddy and others like it. I'll find out. When I install it I'll be sure to check the catch can outlet for oil buildup.

two cents worth

 

Very interesting, the Accurate Machine catch can design and size is almost identical to mine!
And I mounted it inside of the battery compartment to keep it cool.
The main difference is I use a PCV filter media instead of a mesh with rather large openings.
The result is the line going to the intake manifold has remained as dry as a popcorn fart, while the catch can is collecting oil.
I will admit the AM catch can is better looking but I was after function first and it appears to be working quite well.
It looks like I will be changing the filter media at the same time as the engine oil so it will be nominal maintance and cost. (About $.50 per change).

 

ROFL!!!

Yeah, guess I was sucked in by the anodized finishes. Was planning a similar PVC home-made unit, but really like the looks and design description of this one. Hope it turns out as I imagine. Will be checking for dryness and may report back, but not as eloquently as you.

 

The benefit of complete oil removal outweigh the miniscule amount of decreased air flow into intake during a state of vacuum. Which by the nature of driving at various throttle positions(thus increasing and decreasing vacuum or zero) is not constant anyway.

I agree with you for the most part. But a saturated filter element becomes far more effective than a mesh filter at separating out vaporzied liquid. A good example is your stove range hood with those mesh filters that do not remove vapor or smoke but large droplets. In order for the filter to benefit from a centrifugal effect the air must spin quickly and the PCV does not have a fast enough flow to create an internal centrifuge. The air flow in CFM is huge on an air compressor as apposed to the small air leak created by the PCV system. Apples and oranges comparison. That is why I advocate reversing the flow because you get a wicking action from a basic filter.

Yes to cool but no to mesh being better than a closed, saturated, filter element. Otherwise your coffee filter would look like a brillo pad.

For test purposes, place a cambell housfeld filter after the AMW catch can and you'll see just how much your $80 unit is missing. It won't hurt to run it that way for a few days and will put this issue to bed. Or send me yours and I'll test it. Either way.

Me too!

 

This is all good and well and a great mental exercise, but it should be understood that the PCV system is an engineered system that looks at many different factors, two of which are flow and pressure, and putting something in the system that changes those two parameters will affect the performance of the system as a whole. I could go into the design of the PCV valve requiring data on the crankcase pressure relative to the intake pressure at varying RPMs since the weight of the check valve is dependent on the differential pressure created between the two areas, etc., etc., but my logic boils down to this, if you can modify a system for a gain without causing the system to operate outside of design parameters (in this case remove oil without creating a restriction in the PCV system) or you can adjust the other design parameters accordingly (e.g., tune PCM to adjust air/fuel for headers), then it's a safe modification. Otherwise.........

 

Well that's quite a summation. But I'll continue to argue this point.
First, let's discuss the "air leak" called the PCV. Yes the valve is specifically designed to air flow. But stop there. The valve prevents air flow back into the crank case not visa versa. Go try to blow thru it. It closes when the air flow reverses away from the intake. It's weighted to specific engines because of varying amounts of vacuum from a V8 to an in-line 4 banger. So, no, you are incorrect in the assertion that the valve prevents sucking oil up from the crank case. Otherwise we would not be having this discussion at all. you are focussing on the engineering design and not the engineering purpose of the PCV.

But let's be clear here. The PCV system is not a performance enhancing addition to your engine. It is "GREEN" only. Simply a way to passify the Gov. with regard to unburned vapors exiting the engine. You could vent the crank case to the atmosphere and cap the intake port completely and be done with it(as some here have done). The vent would relieve the crank case pressure developed by a rotating crank shaft and potential blow-by. You can try this at home kids. disconnect the PCV and cap the port. You will see no ill effects to performance. And understanding this would elay any fears you have in regards to slowing the air flow thru the PCV system. Thus the small "air leak" is unimportant in comparison to oil being burn via the intake. period.

The PCV is not required!

Understanding that, will cover all your other points.

But, since the PCV is still installed on your car, stopping the oil vapors in total and not just letting them swirl by a brillo pad before getting burned in the engine is the main goal. IMHO

 

I'm not a motorhead, so forgive me when I chime in here, because, I too, and interested in a solution to catching the oil before it gets into the manifold:

Would it be safe to say that if the intake vaccum is NOT equal to, if not higher, than the crankcase pressure, we're going to have problems?

If so, then how do we know that the little CH filter can handle the flow-through on BOTH ends?

I remember reading Chuckster's results when we did track runs with and without the mod on, and others chimed in saying they, too, noticed loss of power due to the CH filter in its stock state, and that removing the element inside the filter seemed to alleviate the problem.

Could it be, based on all the scientifc theories on this thread alone, that under "normal" driving and circumstances, flow is adequate through the stock CH filter, but under higher loads, eg. hard acceleration, there are problems? For example, if the vaccum from the intake increases greatly upon acceleration, and the flow is fine through the filter to a certain point, but drops significantly because maybe the vaccum at the intake gets too strong for the filter to allow, would the computer sense this (not because of the MAF, but because of other feedback AFTER the intake) then adjust fuel mixture/delivery and/or timing to compendsate, thus resulting is a "loss" of power?

If so, then it makes sense that capping the intake completely works because the car does not see the volume of air coming into the intake rise on acceleration, then suddenly "flatten" a bit as would happen if a restriction occurred, right?

This makes more sense as to why some people noticed the degradation of performance. On the other side of the issue, I believe the crankcase pressure does not get very high. Obviously, if it did, we wouldn't be able to just vent to the atmosphere as some have done.

So, the real aim here is have SOMETHING in line that does not impede the flow on the intake side of the PCV valve, given that it's supposedly a highly engineered system in itself that accommodates for things like vaccum, advance, etc., but that SOMETHING should serve to at least reduce the amount of oil being ingested at the intake, right?

So, after all this back and forth banter, although I have yet to find someone who'll step up and say, "Yes, the CH filter mod works to catch some degree of oil, but won't negatively affect performance", with or without the element inserted into the filter, but no one seems to be saying anything about performance issues with the other catch-cans, but DO raise issues as far as which is more effective at trapping oil.

With all that said, I'd be more interested in knowing which would work for me to even reduce oil, if any, that gets by my PCV valve without restricting flow into the intake.

Thanks for listening and your consideration.