uvamosk

Hey guys,
So I have looked and looked and I can find all sorts of information on catch can setups on turbo engines.. I haven't found any good info on NA setups.

I was wanting to know if anyone could help me out. I want to run a catch can on my B20B setup and didn't know for sure the proper way to hook it up.

I have been told a vacuum on the crankcase helps So was trying to figure out a way to run it so that the catch can would have a vacuum on it?

Should I just use the two hex nuts on the back of the block and hook my catch can there and vent the catch can or would that not be as good as having a vacuum on it?

mouab18c1

iTrader: (5)

It's the same concept for N/A and FI.

uvamosk

So Should I just remove the PCV valve entirely?
run both hoses to my catch can and vent?

mouab18c1

iTrader: (5)

Yeap

uvamosk

How would this effect the PCV system?
The PcV valve is there to supply vacuum at no throttle and partial throttle so that it can suck out gas from the crank case.

94eg!

iTrader: (2)

It deletes the PCV system. It just becomes an open/vented crank-case system. You engine bay smells like oil fumes and everything.

You can also add a pcv valve on or after the catch-can. Then you can run the line back to the intake manifold. In this case, you will still need to have the tube connecting your intake arm to your block or cylinder head. This will supply the fresh air to the block and allow the fumes to be drawn into the intake manifold through the pcv valve. The idea is that catch can will better allow the oil vapor to condense before it reaches the intake manifold. This helps keep from consuming oil and/or contaminating your intake air.

With either setup you will have to decide if you want the catch can to drain back into the block or not. It's up to you. Lost of people advise against the return line because it keeps fuel & water vapor from condensing and thereby contaminating the oil. On the flip side, If you have lots of blow-by, you do run the risk of either overflowing your catch can or removing too much oil from the sump (someone swears this is why they spun a rod bearing in another thread). If you don't do the return line, you should keep a close eye on your oil level as well as how much oil is being collected by the can. You don't want to puke oil all over the engine bay either.

You cannot pass a visual inspection with a vented catch can (if that is a concern in your area).

If I were to use an aftermarket catch can, I would definitely build a kit around the AllStar Performance one. It's inexpensive, internally baffled, and looks nice too. It can be purchased with one port or two depending on how many ports you add to the back of your block:

https://honda-tech.com/forums/all-motor-naturally-aspirated-44/breather-catch-can-baffling-pics-allstar-36109-a-2778949/



Here's the parts you need to add to the back of the block:



This is how you setup your hoses for drain-back (mount the can high in the engine bay):

uvamosk

94EG! I was going to PM but decided to keep this in the thread so others can access the information.

The setup you nicely layed out above is block venting. I have read from lots of different sources that OIL creeps up the lines during hard accelleration and fills the catch can up very fast.

The information you provided was helpful. I am going to draw up another diagram tonight of what I am thinking of doing.

I looked through the FSM and other places and have a better understanding of the PCV system on the B20B. I also have found out that the system is udner vacuum at no throttal and partial throttle.
During wide open throttle the PCV valve shuts and the gass is vented out the breather hose...

I think I may just delete the PCV valve.
Then run a line from the where the PCV valve was to the catch can and another line from the breather tube to the catch can and vent atmo.

I have another Idea to setup the catch can but I would need 2 check valves and a little extra line.

94eg!

iTrader: (2)

Yes those pics are of a vented system, but you can always replace the filter with a grommet and PCV valve for daily driving. Just run a tube from the PCV back to your intake manifold. Then if you go racing, pull the tub, cap the manifold nipple, and install the filter on top.

Here's a pic of the grommet & PCV included in the Endyn breather kit to make it a closed system (and the link shows it installed):

http://www.team-integra.net/forum/20...y-b20vtec.html



As for your comment about WOT, the PCV doesn't necessarily close. It may depend on what rpm the pressure waves from the intake valves can cause positive pressure in the intake manifold (if any). But if you think about it, a street engine very rarely sees these events. Additionally, the psi inside the block is almost always going to be higher than that inside the intake. The PCV is just there make sure it won't spit fumes/oil back into the intake track if that does happen.

I'm running a Type R swap (B18C) with a stock black-box catch-can on the back (I know B20 is different). I had always worried about contamination back into the intake from the valve-cover, so I installed a clear tube back to the intake arm. I've had it on over 2 years and there is no evidence whatsoever of oil or oil vapor backing up that tube. It's still glass-clear with no fluid. This PCV system is doing it's job at over 8k rpm. There may be a hint of oil vapor making it's way through the PCV, but the stock black-box has 3 baffles and should do plenty to minimize it for sport/street driving & emissions sake. Plus I'm sure the vacuum at part throttle helps the engine to run better as well. At one point I did install a clear tube from the PCV to the manifold, but it was unable to withstand the vacuum & heat for very long. In the short time I ran it, I only noticed a tiny bit of oil at the PCV. No evidence of liquid oil actually making it to the intake manifold.

94eg!

iTrader: (2)

I think you should do the following:
- Remove the PCV valve from the B20 valve cover
- Plug the hole on the valve-cover
- Add the two large nipples to the block
- Run hoses from those two nipples to the new catch-can (with or without drain-back tube)
- Get the proper size grommet & install your PCV atop the catch can
- Run a hose from the PCV to the intake manifold.

uvamosk

I might just take your idea but tap the hoses into the valve cover.
I'm worried about what I hear with block venting and how it fills the can up fast.
If I just replace the pcv valve with a fitting and run it and the greater nipple on the valve cover to the catch can and vent atmo I should be good to go..

What ya think?

94eg!

iTrader: (2)

You could just leave the PCV vale and run the hose off of that. If you run other fittings from other places as well, you will need a second PCV valve before the intake manifold. No big deal.

Also, if you run off the valve-cover, you won't be able to plumb a drain-back because the oil probably won't flow up to the valve-cover.

EsotericImage

iTrader: (8)

the main reason the can fills up fast is cuz people use too small hose. The larger the hose used, the more the oil will separate and drain back into the block. 5/8ths hose should be fine to use for venting.

96dxB16

I'm the one who spun a rod bearing because I didn't drain back to my pan on my catch can. My catch can filled up and actually started puking oil out. I was out on track so it happend pretty quick. I was in a high g load turn, long sweeper and saw my pressure drop from the loss of oil. Immediately got off it and pressure returned, but the damage was done and started to hear it knock. Was only #4 rod that went, but had to replace the crank and rod.

I never pinpointed the exact issue being how the hoses were ran or a missing drain back.

I originally had it run off the OE breater on the vc to the can, then the 2nd hose was from the top of the black box to the can. Then vent to atmosphere. I'm not sure if oil traveled up the black box into the can or through the vc. I was using 5/8' hose at this time.

Since then I made a vented new can and added 2 more ports to the VC to run -10an lines to a new can that drains back into my moroso pan (glad it was already tapped). I also removed the black box and plugged that hole on the back. All venting is now done through 3 ports on the VC that run to a can that drains back.

I notice oil still gets into the can (quite a bit) but at least it is going back to the block to avoid starving agaiin. I don't know why i have so much blowby or pressure. My compression is 255psi across the board and have minimal leak down.

This is a road racing car on slicks.

EsotericImage

iTrader: (8)

hmm.. got any pics of ur set up..?





Anyone know what size that allen size is thats in the pic?

94eg!

iTrader: (2)

Those pics have been circulating around Honda-Tech for well over 7 years. Here is a thread with some pics directly from the guy at Endyn that helped pioneer these breather systems on LS/CRV blocks. I can tell you though that the all-clear tubing won't withstand vacuum once it's heated up. If it's not hooked up to the intake manifold, then it doesn't matter. And nevermind the extra breather canister he added in front of the motor.

Last post in that thread says they are 14mm hex.

http://htarchive.org/showthread.php?t=1176649

EsotericImage

iTrader: (8)

After researching for hours, I found the Endyn catch mods the block nipples to point further into the block to catch more vapor and less oil.. They only pass the threads 1/4" or so, but seems to be very effective.

Theres so much back and forth confusion on 5 different threads.



I saw his set up on the VC to the catch with the clear hoses.. I know this is the all motor thread.. But I have yet to see a system that pulls vacuum (when in vac) and also evacs crank pressure when in boost.. The only thing i saw was to weld a nipple on the downpipe to draw vac (as the FI IM is useless for vac under boost) but then u have oil and oily vapor going right into the exhaust.. no bueno.

Ill have to keep searching, but Ive spent all morning searching and still havent found anything. I also read that OE FI cars (subaru, mazda, etc) have just a normal PCV set up.. I guess like honda, they build them for people who a are barely in boost and mostly in vac as they are DD's.


But, for an N/A set up, the catch set up is pretty simple.

94eg!

iTrader: (2)

An OEM Turbo PCV system uses the PCV valve to keep the intake manifold from pressurizing the block. When under boost, the system simply allows crank pressure to push itself out into the intake (before the compressor). This is the exact same way a Honda PCV system works. With a turbo, you just wouldn't want to modify your PCV system and add a slash-cut tube to the intake port (as Endyn suggests). If you did, your normal crank-case pressure will have to fight the oncoming intake charge when under boost.

By the time you build your breather system, your gonna be an expert on this subject.

EsotericImage

iTrader: (8)

LOL

spAdam

iTrader: (1)

Semi-back-from-the-dead...

daily driver N/A build here. Pretty mild, high compression b20 non-vtec. Your description is just about exactly what I want to do. What I would like to add to it is some sort of a check valve equipped filter on top of the can. It should purge any positive pressure under WOT, but will pull vacuum through a pcv valve back to the IM under cruise and off throttle conditions. Any input?

EsotericImage

iTrader: (8)

what I ended up doing was using the OE PCV system, then vent off back of block. That way when not in boost (95% of the time on street) the engine gets fresh air. Then when pressure builds, the PCV closes and vapor is forced out the vent.


I used a new PCV grommet and its pretty snug and been working great so far.

spAdam

iTrader: (1)

If I had the vent on the back of the block I would put a baffled can on it and plumb in and call it a day. The vtec blocks have decent evac stock. Non vtec b20 here, nothing but the valve cover straight to the im.

EsotericImage

iTrader: (8)

^^
This is true if your NA and since the B20 doesnt rev too high the OEM system should be fine, but if your boosted, the rear vent is needed.

spAdam

iTrader: (1)

I just realized that I actually quoted the wrong post in my post, lol. So I'll put it here and hopefully it will make more sense.

Daily driver N/A build here. Pretty mild, high compression b20 non-vtec. Your description is just about exactly what I want to do. What I would like to add to it is some sort of a check valve equipped filter on top of the can. It should purge any positive pressure under WOT, but will pull vacuum through a pcv valve back to the IM under cruise and off throttle conditions. Any input?