The Official Crankcase Evacuation thread for Turbo Hondas / PCV / Catchcan /

[dasher]

This thread marks the conclusion to my preliminary tests started over 1 year ago. You may want to familiarize yourself with the purpose and function of the stock PCV system with my original thread first. http://www.honda-tech.com/zerothread?id=697498 The purpose of the stock PCV system falls under 3 categories: 1) Performance 2) Emissions standards 3) Reliability Performance It is well known that performance gains can be had if the crankcase is under a slight source of vacuum which helps reduce crankcase windage losses. Many domestic users have seen decent gains by using either an electric or mechanical pump to help evacuate the pressure generated in the crankcase and even generate a vacuum present. Regaining lost power through the introduction of vacuum pressure evacuating the crankcase will not be as noticeable on a small displacement 4 cylinder as compared to a larger displacement 8cyl domestic. Despite this, it should still be of importance to explore the various configurations and attempt to "free-up" any power hidden in our engines which can easily be tested on a dyno. Emissions Standards and Reliability In order to comply with US emission standards honda had to use a closed PCV system which eliminated oil vapor from escaping into the atmosphere either from the valve cover or the crankcase breather. Oil vapors being introduced into our cylinders hurts performance and increases the probability of detonation occurring. The stock PCV system allows for the introduction of oil vapors into our intake manifold which hurts performance and reliability(a stock intake manifold is usually caked with collected oil and soot over the years). A stock PCV system is far from an optimal configuration in terms of performance and reliability. The best arrangement is to create a vacuum inside the crankcase of 14-15 inches/Hg (7psi). You do not want to create higher vacuum than 15 in/Hg because you will begin to suck oil from valve guides, piston rings, and bearings which will have dramatic consequences. Inducing a vacuum in your crankcase will lower oil pressure slightly which may be alarming but shouldn't be because the oil volume is still present. 2-5 % increase in whp is not uncommon with a properly setup vacuum drawn crankcase pulling 15in/Hg. This Vacuum will quickly remove unburnt Air/Fuel from blow-by gasses. Blow-by contaminates engine oil, contributes to sludge buildup, and causes corrosion. Turbocharged and Supercharged cars have significant amounts of blow-by because of the pressure created inside the cylinders. Your first priority should be to attempt to create a vacuum in the crankcase to remove the blow-by or at minimum make it as easy as possible for this pressure to escape. Evacuating the crankcase pressure can be done directly from the block or valve cover. It doesn't matter which method you prefer. Test Engine: B18c1 /// Freshly built Engine- leak-down #s 2-3% across the board -- 9-1 CP pistons/Eagle Rods/Victor X Intake manifold/Lovefab sidewinder/ Arp Head-studs -- 3" Down-pipe/3" Moroso Spiralflow resonator/3" mandrel exhaust/open dump-tube/ Tial 40mm waste-gate -- Freshly Built Head/ Supertech valves/ Titanium retainers/Dual Valve springs -- Fresh Garrett 4 bolt t3/t4 turbo// 0.60 AR Compressor/ 0.63 Turbine housing -- Custom 2.5" intercooler pipe/ Custom Spearco 3.5"X12"X20" intercooler -- Tuned with Hondata Test Equipment: Calibrated Dewyer Magnehelic Pressure Gauge 0-5 psi range // Accuracy +-2% /// ----------------------------------------------------------------------------------- Open Breather Ventilation ----------------------------------------------------------------------------------- This method is adequate for ventilating crankcase gasses in turbocharged/supercharged cars because the extra blow-by will force its way through any filter quite easily. You want to make sure you provide as many sources as possible to allow the pressure to escape with ease. For H, F, and D series engines you can use the stock PCV line(excluding the PCV valve), Breather Line, and tap an extra 1-2 ports in the valve cover if wanted. You can attach a filter directly to the line or connect them to 1or2 catchcans with a breather filter on top. You want to place the catchcan in the highest possible location you can locate in your engine bay. This will allow the catchcan to collect blow-by gasses without consuming excessive oil and allow a drainback line to easily flow oil/gas mixture back into the engine(if you choose to use this feature). The sole purpose of a catchcan in an open breather system is to "trap" oil and blow-by gasses so they do not contaminate your engine bay and the environment. The surface area in the lines and the catchcan facilitate this. Increasing the surface area by using steel wool or other means will certainly help capturing these gasses but will also restrict them from escaping. The best compromise is to use a baffled catchcan such as one Moroso manufactures. On B series engines it is preferable to ventilate the crankcase gases through 2 ports located on the back of the block. This arrangement can be accomplished by removing the PCV chamber behind the Intake manifold bracket and sealing the stock Crankcase ventilation hole. If you are running the stock Intake manifold you will want to also plug the PCV port on the Intake Manifold as well. The Crankcase ventilation hole can be sealed with one of these 3 methods: 1) Aluminum Freeze Plug (34.4mm-34.6mm) 2) Aluminum circular plate epoxied with Devcon Liquid Aluminum http://www.devcon.com/devconfa...id=34 3) http://www.z10eng.com/ makes a plug. It is important that you seal this opening with an Aluminum plug and not a rubber one! Remove the ports with a 14mm Allen(Snap-on) and install these 2 washers and ports as shown below(Honda part numbers shown): Use reinforced high temp hose 5/8" ID. Their will be a port on the top of your block which normally connects a line to your PVC chamber. You can either seal this or T it off one of your ventilation lines. The last thing to do is place a small filter on your breather port located on your valve cover. I ran this above setup for approximately 1 year with no problems. My car was daily driven hard boosting 17-18 psi. I tested this setup using the following configurations: 1) Drain-back feature to the one of the original lines 2) Back to the oil pan 3) Without the drainback feature. When I removed the drainback feature I would fill the catchcan half full every 2-3 weeks. The evacuation lines would dis-color but never suck oil even when I used the stock Honda fittings without an anti-siphon tube. The contents of fluid collected inside the catchcan was mostly unburnt fuel and contaminants with very little oil. If you are experiencing excessive oil consumption in the catchcan I suggest you place your catchcan higher or do a leak-down test. I suggest manually draining the catchcan instead of using the drainback feature to eliminate gasoline and contaminants from re-introducing themselves to your oil. Bottom Line Cost: 20-150 dollars(dependent upon open filter lines or use of catchcan) Performance: Good(as long as their is enough ventilation) Reliability: Good. Environment: Horrible(no catchcan)- poor(Catchcan) ----------------------------------------------------------------------------------------- Intake Manifold Vacuum Assisted Ventilation ---------------------------------------------------------------------------------------- In Turbocharged vehicles the Intake manifold sees both vacuum and boost pressure unlike in naturally aspirated cars. The PCV valve acts as a check valve blocking any pressure in the rare occasion their is backfire in the Intake Manifold. I have heard that some individuals placing a check valve in-line and allowing the Intake manifold to assist in ventilating the crankcase. The check valve insures that boost pressure doesn't enter into the crankcase through this line. Ideally one would want to induce a gradual amount of vacuum up to 15 in/hg under full load. Connecting the evacuation line to the intake manifold would do the exact opposite of this. On a boosted vehicle the Intake Manifold will read 25in/hg at idle and 20-15in/Hg in low load conditions and quickly disappear when any moderate to high load conditions appear. In a stock vehicle this is acceptable because the PCV valve meters the vacuum as shown: Idle, Low load--- high vacuum pressures fully retract the pintle causing only a small vacuum draw on the crankcase. Mild load conditions--- vacuum present in the intake manifold is not as strong so the pintle sits in the middle of the pcv valve allowing more vacuum to evacuate the crankcase. High load + WOT conditions--- their is almost no vacuum present and the pintle is almost completely extended allowing the most amount of gasses to be drawn into the intake manifold. Engine backfire--- the pintle fully extends and seals to eliminate any gasses from flowing from the intake manifold to the crankcase. Not only are you pulling excessive vacuum at low load conditions you are contaminating the Intake charge with oil and unburnt fuel blow-by. I cannot recommend this setup to anyone. ----------------------------------------------------------------------------------------- Intake slashcut evacuation ----------------------------------------------------------------------------------------- Using a slashcut tube to create vacuum is an old trick which works on the Bernoulli effect as air rushes past the tube at high velocities. Make sure you place the slash-cut opening in the opposite direction of the airflow. One method for evacuating the crankcase is to allow the Intake(pre-turbo) to draw out these gasses. In my tests their was a linear load dependent vacuum drawn using this method. None to insignificant amount of vacuum drawn at idle and low load conditions, moderate load created 0.25 psi(0.5") of vacuum, and high load/WOT created a maximum vacuum of 0.5 psi (1") vacuum. One does not need to use a check valve with this approach as their is never any reason for pressure to force its way into the crankcase. Their is a positive and negative aspect to this approach. The great thing about this method is that it is the only method which allows one to completely eliminate any blow-by gasses from contaminating the environment. The downside is that it contaminates the Intake charge with oil/fuel/contaminants. Judging from the amount of contaminants I collected in my open breather catchcan every 2-3 weeks it would be absolutely insane to use this method without a sealed(no open breather element) and baffled catchcan in-line between the crankcase /valve cover and the intake. Keep in mind that most of the contaminants will be sucked into the intake as opposed to only some contaminants trapped in an open breather catchcan while the rest pollutes the environment. Some good news is that the Intercooler piping and intercooler will act as a very large catchcan and trap most of these contaminants before they reach the engine. The bad news is that I suggest you periodically clean the inside of your intercooler and intercooler pipe. Bottom Line Cost: 20-150 dollars(dependent use of catchcan and welding) Performance: Good(as long as the compressor housing/Intercooler are cleaned periodically and a catchcan is used) Reliability: Good. Environment: Excellent(provided that you use no other open breather elements) ----------------------------------------------------------------------------------------- Mechanical Vacuum ----------------------------------------------------------------------------------------- The only people right now that make this for Hondas is: http://www.z10eng.com/. The great news is that this is the best setup from a performance/reliability perspective bar-none. The bad news is that it is extremely expensive and you have to run their complete oil pump setup thus loosing your AC compressor. My conversation with one of the owners a while ago led me to believe these guys are extremely knowledgeable and will customize your complete setup specifically to your needs. You can choose between a dry sump, wet sump oil system, or even add on a mechanical fuel pump. The vacuum generator can be manually adjusted for desired amount. Expect to free up more whp then the standard 2-5% because this setup goes way beyond simply inducing vacuum in the crankcase. Bottom Line Cost: Variable. Expect around 2 grand. Performance: Excellent. Reliability: Excellent. Environment: Poor. ----------------------------------------------------------------------------------------- Electric Vacuum pump ----------------------------------------------------------------------------------------- I have studied and tested the idea of using old electric brake booster vacuum pumps which were made for old GM vehicles to induce vacuum in the crankcase. Using an off the shelf electric vacuum pump to draw a specific amount of vacuum is tangled with complex problems. These pumps run 16in/hg of vacuum at 13.7 volts and 19in/hg at 16 volts. Remember you don't want to draw more than 14-15" of vacuum and it is preferable that the vacuum is gradually increased in a linear fashion with load which these will not do without some tricky electronics. I have studied both mechanical and electronic approaches to solving these dilemmas to no satisfaction. After all the problems I had wrestling electrical gremlins in an electric water pump I simply don't trust my engine on this device. Another cause of concern I have is when my alternator failed while I was driving I recorded very unusual voltage numbers jumping from 10-16.8 volts in odd patterns which could case problems for an electric vacuum pump. ----------------------------------------------------------------------------------------- Exhaust slashcut evacuation ----------------------------------------------------------------------------------------- This is based upon the same Bernoulli effect mentioned before but uses exhaust gasses to draw out crankcase gasses instead. Their are 2 ways of doing this: 1) Weld a slashcut tube in your waste-gate dump-tube 2) Weld a slashcut tube in your exhaust In the first test I connected my Dewyer Magnehelic Pressure Gauge to the slashcut in my wastgate to measure the vacuum draw. As expected I only saw maximum vacuum drawn when the wastgate was open after reaching my maximum boost pressure set on my boost controller. The amount of vacuum went up from 0.25psi(0.5") to 0.4(0.8") vacuum. The numbers shown here were very similar to those shown with the Intake slashcut with the exception of being present when the wastgate started to open. I chose to connect my valve cover breather and top port (oem- not modified plugs) on my block to the waste-gate slashcut tube. Check valves aren't really needed here but you can use one if it make you feel better. For my second test I welding in a slashcut tube in my downpipe(12" from turbo). At first I had problems melting my high temp tubing with the heat from the downpipe and exhaust so I soldered together some copper pipe to solve this problem. I placed a check valve in-line on the top 6 inches of hose and wrapped it in reflective heat wrap as you can see. At Idle the Dewyer Magnehelic Pressure Gauge showed 0.1-0.2psi of vacuum. Driving around town was more unpredictable. The gauge would oscillate between positive pressure(when i tested without the check valve) to 0.5 psi (1") to 1.1 psi ((2.2"). It rarely displayed positive pressure but I could find no simple pattern either rpm or load dependent. Typically it would bounce around 0.6psi to 1psi. Here is a picture of the hose connected to the valve cover port without being tested. You definitely want to run a one way check valve in-line here. I purchased the check valve for 1 dollar at a local junkyard. You can find the check valve in-line on the brake booster line on any honda. Another source for a check valves and slashcut tubes(In case you don't feel like cutting your own is Moroso: Bottom Line Cost: 20-80 dollars (dependent upon if you have it welded or not) Performance: Great. Reliability: Great. Environment: Poor. ----------------------------------------------------------------------------------------- List of engine locations of Evacuation lines ----------------------------------------------------------------------------------------- I already have given a detain description of the PCV system found in B series engines. Below are examples for other engines: Modified by dasher at 8:52 PM 4/2/2005

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[boostincoupe]

Hopefully there's no more catch-can drama in this forum thanks to this thread

[98coupe]

Very very Good info. Thanks

[Boosted Chemist]

nice post dude, on your open catchcan breather, where did you run your intake breather, did you use a small kn filter or run into the can?

[dasher]

feel free to critisise any of my tests and testing methods.... empiricism is what I'm after, my ego can suffer.

[dasher]

Originally Posted by Boosted Chemist

nice post dude, on your open catchcan breather, where did you run your intake breather, did you use a small kn filter or run into the can?

Small k/n breather filter. You want to make it as easy as possible for the air to escape using an open breather arrangement.

[igo4bmx]

does the open breather catch can setup offer any vacuum?

[evosol]

nice info, i think i'm gonna try the exhaust slash cut style since emmisions is not of concern.

[dasher]

Originally Posted by igo4bmx

does the open breather catch can setup offer any vacuum?

No. But it does a fine job if setup correctly. Their are better methods as explained.

[dasher]

Originally Posted by evosol

nice info, i think i'm gonna try the exhaust slash cut style since emmisions is not of concern.

Make sure you weld the tube in the correct way. Slashcut facing away from moving exhaust flow.

[mike1114]

Great Post!!!!

One quick question, I didn't see a test using one of the ports on the back of the block and the port on the valve cover similiar to the open breather ventilation method, what would be the drawback to doing it this way?

[dasher]

Originally Posted by mike1114

One quick question, I didn't see a test using one of the ports on the back of the block and the port on the valve cover similiar to the open breather ventilation method, what would be the drawback to doing it this way?

Your asking about using 1 port on the back of the block of a B series engine instead of 2?

All this means is that their will be less ventilation. Won't be that big of a deal, but slightly worse. With an open breather setup you want as much ventilation as possible.

I remember a thread a while back were someone was suggesting using only 1 of the 2 ports with on the rear of the block to cut down on it siphoning oil. I never had this problem using both ports and without the use of anti-siphon tubes in those fittings.

[mike1114]

would some excess ventilation not come out the valve cover port as well?

[dasher]

Originally Posted by mike1114

would some excess ventilation not come out the valve cover port as well?

Yes. The more important aspect is size of the openings, the size of the lines, and the amount of filter surface area which the air can escape from.

Running 2 catchcans would be better. Making another port on the valve cover with a second small breather filter would be nice too.

You do have diminishing returns however....

[ScottEK]

I appreciate the time you put into putting this together

[dasher]

Originally Posted by ScottEK

I appreciate the time you put into putting this together

No problem. I promised I would over a year ago, and I did. Better late then never.

One more note.... If anyone is going to use the Exhaust slashcut tube method make sure you do not run a cat and that the slashcut tube is below or after your O2 sensor.

[EJ1 wilcox]

Yay! The wait is over!

I am going to have to read over this again and study it later... I'm a few drinks deep right now so I have a hard time focusing at the moment!

Thanks for putting the time, effort, and money into the research... I for one, really appreciate it!

[Bailhatch]

How does that gauge read vacuum?

[D-tuned]

Great write up. H-T apreciates the time and effort that went into doing this test.

[stealthmode62]

Very informative non biased stuff here. Nice job.

[Syner-G-Racing LLC]

[Tchleung]

dasher, what do you think about this setup?

http://www.honda-tech.com/zerothread?id=935871 You can add catchcans in the appropriate spots easy.

[dunkd]

thanks for explaining this...

[Tony the Tiger]

Dasher, great write-up! I give

Anyway, I am running an exhaust PCV setup, and I noticed I get a good clean -4 to -5 inches of vacuum that gradually increases as RPM and load increases.

I am wondering if your test car is running a catalytic converter? If you put the slash cut tubes before the cat, you will end up with pretty bad vacuum (and sometimes positive pressure) at the slash tubes. I had mine relocated to after the catalytic and it got much better results. Reason for this is that the catalytic converter is a highly restrictive portion of the exhaust, and anything before the cat will generally build up pressure as load increases.

If the bungs are after the cat, the exhaust is going from a high restriction to a lower restriction portion of the exhaust. This will effectively put the Bernoulli effect to use

[untuned]

good write up