More Oil Catch Can Contents
 

I generally try to empty the catch can while I am filling up with gas, so this is what has accumulated in my catch can since the last fill-up. I was hoping I could get help identifying the contents, and perhaps diagnosing potential problems.
Attachment 191472

As you can see, there are 4 distinct layers in this suspension:

1. - Top 1/3rd - Solution - Translucent Red in appearance - Based on smell/feel this solution is primarily gasoline. Is this a product of running too rich?

2. - Third 1/6th - Colloid? - Opaque white in appearance - Is this an aerated water/oil mix?

3. - Fourth 1/6th - Colloid - Opaque dark grey in appearance - I'm assuming this is a water/oil mix?

4. - Bottom 1/3rd - Solution - Translucent Amber in appearance - I haven't actually stuck my finger into it, or taken any of it out, but based on density and color, I am assuming this solution is primarily water. Does this water condense out of the air during the compression stroke?

You'll get the gasoline by condensing vapors from combustion chamber blow by. Thats the primary function of the vapor capture coming off the motor (PCV).

From a density stack position I would think you guessed right...
Gas 730 kg/m^3
Oil 880 kg/m^3
Water 1000 kg/m^3

They should stack up just like that.

This is a very cool picture!

this is a good POST!
for other members when looking for info

I get about that much in my can after an entire day, but mine looks more like cappuccino.

Same here. Until you let it sits for a long time.

When I start it up on a 40 degree rainy day it fills up quickly with mostly water.

I've been thinking about trying to pull a small vacuum on it to suck moister out of the crank case. A good separator system a check valve and using the exhaust flow in the tail pipe to pull a vacuum on the crank case breather system would be the plan.

A friend of mine gained 18 hp on the dyno on his 250 hp civic by pulling a vacuum on the breather system using exhaust flow. A 5/8" pipe cut at 45 degrees welded into the tail pipe pulled a few inches of vacuum on the breather can. Sucks all the blow by out the tailpipe and makes the rings seal better.

Bob

That's phenomenal. I'd never guessed that a slash cut tube at the exhaust would make that much of a difference on that little hp. Where was the tube located in the exhaust? I'm guessing closer to the front- which would mean removing the cat for those so equipped.

needs whipped cream

http://1.bp.blogspot.com/_1yeY6af0uS...ayer+jello.JPG

correct, no cat just slash tube in a 3" straight through exhaust Disco Potato turbo setup check valve in the line. Very similar to what they sell for V8 cars seen here as a crank case evac system.

http://www.summitracing.com/parts/SUM-120108/

I have also been considering electric pump idea. See post 17.
http://forums.corvetteforum.com/c4-f...-it-works.html

But the slash tube seems like a simpler less problematic solution. Instead of a breather filter on my catch can I would just run a -10 line out the top to a fitting in the exhaust after the O2 sensor bung, I’m thinking in the test pipe I have in place of the cat.

Bob

Yeah I"ve told others about using the exhaust to create a vacuum in the crankcase, people call me crazy, finally good to see others thinking about doing it.

http://img293.imageshack.us/img293/5184/hpim0153.jpg
By null at 2010-11-13

you can see the o2 sensor and underneath is the tube with slashcut and a one way check valve. That is my downpipe.
I don't see why not to do it, gains you some power, puts a vacuum on the rings and you don't have to suck stuff though the intake to create that vacuum.

So the exhaust flow would actually create vacuum?

I am very interested in options to put vacuum on the crankcase - the simpler, the better. Would it be possible to run an exhaust vacuum on a street setup post cat?

BBundy, the corvette system you linked to has some serious thought put into it. I'm impressed.

Yes, I'm finding that I see my catch can fill up quite a bit quicker in the cold weather.

I know the stock crankcase ventilation system is inadequate for boosted application. I know a lot of us have tried ways to increase ventilation port size, but that success has been limited at best. Has anyone actually found a viable way to increase port size in the valve cover? Perhaps more importantly, has anyone found a way to tap directly into the crankcase to relieve this pressure instead of forcing it through the smallish oil drain passages through the block and head?

Yes with the proper geometry slash tube.

Bob

Yes I can probably post some pictures of what Im doing by this weekend. I have a -10 breather fitting in the side of my block right by the alternator that comes out by the oil sqirter on the inside. Early 1.6l blocks already had a brether port there but it wasnt used on production cars as far as I know after 1987 and just had a rubber cap on it. I drilled and taped the 1.8l block and JB welded a steel AN fitting in place.

Bob

I ran my at first with 2.5" downpipe only, worked fine, after installing my exhaust on and my muffler on it ( flowtech warlock ) still works fine.

with the tube and valve the heat transfer is minimal enough to put a normal hose on it? or better yet... if i welded an AN fitting to the downpipe, would the transfer through the aluminum fitting melt the stainless braided hose?


I was planning to make one of these setups with some -10 hose from my catch can fed from 2 -12 hoses from my valve cover.

I have *desided* that ^^^ moves a pitiful amount of air at idle. Would like to see a chart of pressure/volume at WOT on dyno, though I doubt anyone has produced such data.

bbundy, def in for update.

I've separated the suspension in the original post into three clear shot glasses (top third, middle third, bottom third) and I am currently waiting on the middle third to settle back out into suspension so that it will be easier to further separate into its two subcomponents. Currently it looks like chocolate milk instead of white milk on top of cocoa cripies. I suspect that it will separate within about two hours, I'll post more pics later tonight.

If you consider that the air flowing through the hose is actually relatively cool coming out of the valve cover, your fitting/hose will be air cooled from the inside!!!

Very interested in the vacuum ideas. I was going to just plumb a return to my pan but that sounds much better.

Would this also work with a 3" cat+3" cat back or straight pipes only?

I'd considered this way back, but from what I understood the tube needed to be located near the beginning of the exhaust system to generate good vacuum. That meant ahead of the cat, which is out of the question for those who have emissions (and maintain that standard annually).

I'm extremely interested in this as well. I've been going back and forth about what to do about my catch can setup.

Could one just run the 2 VC breather ports to a tee, and the 3rd line off the tee to the exhaust, eliminating the catch can all-together?

Its actually an aerodynamic effect more then a ring seal effect. The amount of pressure in the cylinder is over a 100 times higher then the few pounds of - pressure created by the vacuum.

By reducing the pressure in the crank case reduces this reduces the air density in the crank case. So following from aerodynamic drag density is a proportional scalar of this drag. So if you reduce the pressure in the crank case to 20% of normal, then aerodyanmic drag will be 20% of what is normally experienced.

http://upload.wikimedia.org/math/9/9...7b238e5de9.png


This system combined with crank scrapers could do an excellent job to improve efficiency and get extra horsepower out of the engine.

I don't see any problem with the system from a reliability standpoint either as the intake manifold regularly pulls the crank case pressure down, this just does it on a larger scale and at loads that matter as far as horsepower is concerned. The actual effect seen here is the bournulli effect.

http://en.wikipedia.org/wiki/Bernoulli_effect

Using the equations here you could probably round about estimate an optimal pipe size to exhaust flow velocity to get suction sucking.

If you’re venting the crank case to atmosphere the cat is pretty much pointless anyway in terms of emissions because you’re creating emissions that don’t go through the cat.

And I don’t understand why it would make much difference where along the exhaust system you put it as long as you didn’t put it in before a restriction. The exhaust flow has the same mass flow rate along the entire distance it losses a small amount of velocity as it cools but it can't be much.

Bob

Ditto and same question. I'm contemplating if I want to run this with my catless 3" exhaust and wondering where the optimal place to mount it on the DP.

Won't pass emission venting to atmos- so the cc vent goes intake preturbo.
I guess the location being at the front was in reference to burning the mix and the impact on efficiency of the length of tube carrying that mix.

I don’t think it would be good to eliminate the catch can it is needed to separate some oil. I've never been able to keep lots of liquid oil from filling up my catch can due to certain cornering/acceleration conditions I seem to see on a lot of tracks. Never a problem on the street though. I don’t mind some blow by going out the tail pipe but I think dumping a cup of oil out in the exhaust every so often would look sort of bad.

Bob

I'm worried about the ability of the cat to pass the expelled contents of the crankcase without eating itself apart. I don't plan to pass emissions testing, but the cat is staying in. This is a 99.9% street car, I care at least some for emissions components - enough to not run a crankcase vent to the exhaust if it means removing the cat.

Somehow I don’t see how the flow rate would be high enough for the line length to be much of an issue.

I’m actually thinking of putting the slash tube in my test pipe where the cat would be and have the components so I could quickly convert my catch tank system into a PCV emissions legal closed system.

Bob

I would think the vent would have to be after the cat or anything else restrictive in the exhaust to be effective.

Bob

Divided into subcomponents - these are 2oz (to the rim of the glass) shot glasses.

The middle third doesn't subdivide very readily, and I don't have a centrifuge, so that's as fine of detail as I'm going to get.

Enjoy!

Attachment 191434

The middle third adheres to the glass, which further increases the difficulty of separating it. You can see where it has adhered to the water glass on the right during separation.

Bottoms up.

LOL, that was one of my first thoughts!

I've been using one of the Summit slash cut/check valve evacuation kits on my old GTO for years. It works well in the header collector. If you drop the breather hose in a gallon jug of water it will suck it dry in just a couple of good jabs on the throttle. You will want to disconnect it if you put your car on a dyno because it will cause the tailpipe o2 sniffer to read incorrectly. And it is better to use it in conjunction with a catch can so that all of that oil doesn't end up in your exhaust (makes a little smoke).

What check valve is that? I am not finding it on summit.

So the routing would be like this?

Valve cover only routed to catch can
catch can VTA
and
catch can also routed to exhaust slash cut.

Or is the VTA in the catch can not necessary?

Jagermeister, Baileys, and Miller Light :X

It wouldn't interfere with a regular WB02 sensor downstream though would it?

Yes, I'm pretty sure it would.

Also, if one had a restrictive exhaust, this wouldn't work as well.

I found a one way valve at summit:

http://www.jegs.com/i/JEGS-Performan...93#moreDetails

It would be nice to find one with threads so I could run AN fittings and braided line instead of something that will wear out.

I thinking having a VTA on the can would defeat the purpose of trying to create a vacuum on the head.

Search for my thread with "tiny hole" in title.

The drain passages are huge compared to the hole I enlarged in the cam cover, and compared to the 1/2" hose and fittings I used.

Replace the filter on your catch can with a hose going to the check valve/slash tube in the exhaust. It needs to be sealed in order to pull a vacuum on your crank case.

I have both the stock ports in the valve cover plus a vent port in the side of the block going to my baffled catch can.

I also have a drain back from the catch can that goes to the very bottom of the sump below the oil level. I think Id rather change my oil more often to keep contaminants from building up than worry about draining the catch can all the time. The water and fuel in the oil should be more volatile so I’m hoping much of it gets sucked out as vapor leaving mostly condensed oil behind.

Bob

Agree on the dubiousness of the claim that an additional few psi of pressure differential between the top and bottom of the pistons on top of the compression and power stroke pressure would make much of a difference.

Having said that, even if the crankcase absolute pressure were dropped by say 2 psi (in the case of the slash cut on the Honda), that's about a 15% reduction and a 15% reduction in internal aero drag which may be what, <2% of the total output?

OK that makes sense. So what about this:

valve cover to catch can
catch can drain to sump
catch can also vents to slash and check valve

Yea, thats true! The magnitude is just off here. I can see a few horsepower, not 50 though. If that much energy was going into turbulence/heat or blow by your oil would be on fire :X

I think it would be worth maybe 5, if the suction was very good!

I was off on my numbers I think 16 hp out of 270. ~6% increase in power my friend recorded on his civic. It made a measurable difference in power.

Bob

Even if the gains are as little as a few hp it still sounds worth it. My biggest concern is interference and possible damage to the WB downstream.

Did he do 2 consecutive pulls with and without the suction connected?

This is true I could care less about a few HP. I’m just looking for a setup that doesn’t put oil back through the intake into the cylinders, I don’t have to worry about the catch can filling up and spewing everywhere, and also not be concerned that I might turn all my engine oil into mocha cappuccino causing engine wear.

I will be putting the fitting in the exhaust after the Wide band so I’m not worried about that.

Bob

I do not know.

Bob

post pics when you get it done!

My understanding of PCV is not very good, but I'm close to Bob in that I'm mostly interested in keeping oil vapors out of my intake tract, and out of my cylinders.
For my last setup, I did as many here seem to, put a breather filter on the cam cover, stock PCV in place. That kept my intake dry for over a year, but over time the filter saturated with oil, leaked, and otherwise put a nice film of oil in a lot of places in the bay.

On my current setup, I'm thinking of doing something different - run a hose from the valve cover breather to one port of a catch can, and put a breather on the other port of the can. Thought being it would trap the vapors in the can and stop the breather clogging. If anyone thinks that's dumb, let me know. This being mturbo I don't really need to ask I guess.

This exhaust vacuum source seems like a cure for turbo oil drain/ring sealing under boost, I'd imagine there was no need for a pcv at that point?

Unfortunately I'd rather not run without a cat. The air pump idea would solve that, but cost, weight, packaging, and complexity make that less appealing.

Place the slashcut post-cat.

Will you get a solid vacuum that far downstream?

doesn't look like that works per cupcar.

If this were doable then installing this is a no brainer for me. But as m2 said it needs to be further upstream to generate good vac. Since I'm running no cat I'd like to have it at least behind my sensor. Anyone think I'd get good enough vac behind my sensor?

Split's old DP which I'm using:

http://sphotos.ak.fbcdn.net/hphotos-...5_840639_n.jpg

Yes you will get fucking good vac there, shesssh,

if you are worried about the crude getting on the cat put a catch can between the Valve cover and the exhaust pipe to catch the crude buildup

The whole point of the catch can system was to keep the crude from being pushed back into the intake system imo, normally manufactures use the engines own vacuum to pull vacuum in the crankcase and for emission reasons to reburn the crap that comes out of the crankcase.

What I don't get is why people put on a catch can, vent to atmo, why not help the engine breath easier as well, put a vacuum into the crankcase, worried about oil going though exhaust? put the catch can on it than, thats why people used

Pulling a vacuum has been going on for few decades now, various ways to do it as well, exhaust, vacuum pump ( elec \ belt ), engine itself, etc

once my miata is running again ( timing belt ) I will grab a video with a boost ( vacuum+pressure) gauge attached to the line and drive it about tad showing it.

My catch can system.

-8 lines to the valve cover vents. Holes have been enlarged in the baffles in the valve cover.

Exhaust side valve cover vent goes into a small manifold that tees into a -10 line going to a port put in the block venting the lower crank case before going to the catch can.

-8 line going from PCV port to catch can.

Catch can is baffled with and a pot scrubber is used. Blow-by has to go down through the pot scrubbers then back up the central tube to get out.

-10 line return drain goes to very bottom of the oil pan.

The filter breather will be replaced with a -10 line going to a check valve and slash tube in the exhaust pulling a slight vacuum on the system.

Bob

Do you have a picture of said port?

Correction: FWIW here's my 1/4 NPT port, for 1/2" hose. Ignore the black hose, it's not part of the system.

https://www.miataturbo.net/attachmen...1&d=1294676439

I enlarged the tiny internal blowby hole. Described here
https://www.miataturbo.net/engine-performance-56/cam-cover-blowby-flow-crankcase-pressure-tiny-hole-modification-54742/

That must be 1/4" NPT. 1/2" NPT is much bigger on the threads. I had issues getting a 90 degree pipe thread to work getting it oriented right when it was tight half the time would crack the valve cover if you weren’t real careful because the wall around the threads gets thin.

Bob