OK the EJ257 has these motor-based vents routed in the PCV "system":

1) passenger cylinder head--inlet and outlet
2) driver cylinder head--inlet and outlet
3) driver-side block--outlet
4) passenger-side block--linked to PCV valve

1, 2, and 3 are linked together by rubber hose and metal piping that snakes around under the intake manfold. The purpose of 1, 2, and 3 is to equalize the pressure between the two heads and the block. Yes? An fair amount of air moves through 1, 2, and 3, but where does it come from? Where does the air enter the system? If there is oil vapor in this part of the system, I've never seen it. Mines been venting into the engine bay for months with no accumulation.

We are left with 4), it is hooked up the one-way PCV valve. When the intake manifold is under vacuum. This valve draws a vacuum on the crankcase (sucking off "blow by" vapors etc). The vapors are pulled off of the crankcase vent 4 and are pushed into the intake track of the stock set up. When under boost conditions, the valve is shut (when it is needed most to collect blow-by.

n2xlr8n has advocated use of GM electric vacuum pump. The only place it makes sense to me, is hooked to solely crankcase vent 4. Yes? The hope is that pulling a vacuum on the crankcase even while under boost will benefit ring seal and thus improve containment of compression (less blow-by).

Am I missing something?

Since I've got WRX heads with single port valve covers, I'll tell you how mine is set up.

Block: I've got both CC breathers from the drivers and pass side block halves being pulled by one-way vacuum valves at the downpipe (or at least they will be very soon when the valves are put in place). Above those CC ports are oil/air separators, this way oil particles aren't left airborn into the exhaust stream under vacuum. On an STI, run these CC breathers to either oneway valves or a pump.

Valve covers: My valve cover breathers are then tee'd into each other where they share a common filter.

PCV valve: Mine is plugged and is no longer routing anything. It was afterall, a big vacuum leak! Besides, other than emissions, what's the point of pulling the CC gases under no boost situations and then it just closes off and then dumps back to the intake. When you actually need the vacuum is under boost, not just cruising around under very little load. This was a compromise of emissions and simplicty.

My recommendation for STI dual port valve covers: Do exactly like I did on the WRX ones and tee the two inlet ports together to a common filter. On the ports that are that are relieving CC pressure, just run those to a vacuum source via check valves or a pump.

So do you think any "blow-by" gas is going to the driver's side vent on the block. I don't. I think the only vent that should be vacuum'd is the passenger side vent that was formerly hooked the the PCV valve.

The way you have your valve covers set up, I'd think that you would see virtually no oil in you oil-air-sep-catch-can. Do you collect stuff off of those?

So you have both of the block valves hooked together-->one-way check valve(s)-->valve(s) opens when exhaust is pulling strong vacuum (e.g. on boost). If the PCV valve was originally only hooked to the passenger side of the block, why do you think the other side has any need for vacuum?

I hate it that I cannot figure out how this rather simple system is routed--both the path and direction that air is supposed to flow.

Thanks for the reply.

So do you think any "blow-by" gas is going to the driver's side vent on the block. I don't. I think the only vent that should be vacuum'd is the passenger side vent that was formerly hooked the the PCV valve.

I can tell you that there's more blow-by coming from the the big un-baffled one (driver side). Maybe not more per se, but it sure seems like it more of it since it's not baffled in the block. They both need vacuum IMO! To me it's not questionable. Try pulling that driver side vent hose off and rev your motor. You'll see what I'm talking about.

The way you have your valve covers set up, I'd think that you would see virtually no oil in you oil-air-sep-catch-can. Do you collect stuff off of those?

I actually removed the catchcan altogether. I now have 1/2" hoses coming off each valve cover to a tee and then share a common open air filter. There's ZERO oil that has ever come from it. Nothing! But remember, you want to run everything uphill so to speak...against gravity.

So you have both of the block valves hooked together-->one-way check valve(s)-->valve(s) opens when exhaust is pulling strong vacuum (e.g. on boost). If the PCV valve was originally only hooked to the passenger side of the block, why do you think the other side has any need for vacuum?

Nope! The idea is to create as much vacuum as possible (to an extent only) with the CC evac system so each block breather (the two on the block halves) have their own oil/air separator and each will have their own one-way valves. This should create about 10" hg of vac at WOT in higher up rpms (speculating based on just a single valve turbo set up, which we'll be using both valves).

I hate it that I cannot figure out how this rather simple system is routed--both the path and direction that air is supposed to flow.

You know, bboy, I used to feel the same way. Honestly I struggled with the idea until spending some time looking at the FSM and the way the engine ingested fresh air and how it expelled spent gases and blow-by. It just clicked not long ago :D

If you're certain that one of the valve cover ports intriduces fresh air, and then the other helps expell blow-by, then like I said above....you can use filtered air for the freshair ones and vacuum to the blow-by ones. Plug the PCV valve and have each crankcase vent to a vacuum source like a valve or pump.

Hope that helps!

Todd

I'll try harder to figure out the two crank case vents (the two on the block) to see if they do benefit from vacuum. I just don't understand why you would go to the trouble of hooking up the PCV valve (and intake vacuum) to just the one vent. From your comments you regard the two cc vents on the block as functionally equivalent. I'll keep looking at that.

I rev my motor and only get oil out of the passenger side cc vent. That's one reason I'll still unconvinced that it "requires" or even warrants a vacuum connection......but then I can't even say where that driver's side hole in the block goes.

I think the only difference is the baffle as they both sit over the crank (more or less). You wouldn't happen to have an extra block around would you? I wish I didn't toss my old 2L in the trash for times like this (it was really screwed up bad though) :)

I didn't hook up the PCV valve at all. It's been completely capped/blocked/plugged off, i.e. no more PCV valve. Like I said above, I came to the conclusion that it was a vacuum leak based on conversations with others in the race industry. The intake vacuum isn't going to be a part of the system anymore. The only sources of vacuum will come from one-way valves like I mentioned above.

My PCV valve is on the floor in the back seat. I think I see what you are saying. The baffle prevents oil from shooting out of the block. I'll look for someone's block that's apart. I think the WRX block is different from the STI, but what do I know.

Thanks.

We are using twin catch cans which both draw vacuum from the intake pre-turbo (one for crank breather and one for head breather). Thus the system draws the vapors through the catch cans and then back through the turbo. Not sure what the story is for the PCV...

We are using twin catch cans which both draw vacuum from the intake pre-turbo (one for crank breather and one for head breather). Thus the system draws the vapors through the catch cans and then back through the turbo. Not sure what the story is for the PCV...

There's no way that the turbo inlet tube is pulling a ton of vacuum though (or atleast I don't see that happening). Maybe low vacuum at best. Then add the catchcans, which will further reduce the vacuum. That's not an idela set up by any means IMO.

The baffle prevents oil from shooting out of the block. I'll look for someone's block that's apart. I think the WRX block is different from the STI, but what do I know.

Thanks.

They're identical except for the extra port on the STI case. The crank is picking up and slinging oil so that's why the baffle is needed. Then add blow-by gas and then it picks up the airborne oil particles and sends them out the unbaffled port...path of least resistance!

OK the new scenario is to:

1) hook together the two cylinder head vents and vent to atmosphere
2) hook together the two block vents and apply vacuum

PCV hose to intake manifold is already plugged.

Hope for positive impact of the vacuum pump, if not call tmarcel and ask about exhaust pumping to use it as venturi vacuum.

Agreed, the intake tube, pre-turbo, is only under very mild reduced pressure. The intake manifold, post-throttle, pulls good vacuum, but only when the throttle is shut. ;)

I'll try harder to figure out the two crank case vents (the two on the block) to see if they do benefit from vacuum.

One is baffled, and the other is not; the "other" sits directly over the spinning crankshaft. I am pulling vacuum at the (rearward)"baffled vent".

S.

One is baffled, and the other is not; the "other" sits directly over the spinning crankshaft. I am pulling vacuum at the (rearward)"baffled vent".

S.
Passenger side rear block vent, but not the driver side front? Or do you just have the one vent?

If you have two block vents and pull vacuum on just one, aren't you just pulling air in through the one vent and out the other (i.e. no vacuum, or little vacuum).

Passenger side rear block vent, but not the driver side front? Or do you just have the one vent?

If you have two block vents and pull vacuum on just one, aren't you just pulling air in through the one vent and out the other (i.e. no vacuum, or little vacuum).


I guess the reality is, that even if you're just pulling one of the vents on the CC, it would be fine if you can pull enough vacuum. Either way, you still need to evacuate the case. In my scenario, I believe that pulling from both is neccessary since the venturis probably won't pull enough vacuum by using just one of them.

I think you've got the idea! Why not just get you a cheap vacuum gauge (for testing the vac system) from PepBoys or the like and tee it in. This way you will know whether or not if you've got the desired vacuum.

Well if you you are pulling air through the crankcase, this is ventilation and will remove any positive pressure and blow-by gas. I thought the idea was to have an actual vacuum, negative pressure, much lower than atmospheric, such that rings don't flutter off of the lands during the power stroke.

Some sites on the net are advocating between -10 and -15 in of Hg worth of vacuum. If one of the vents is open and one attached to vacuum, I can't imagine pulling more than about -1 in of Hg vacuum on the crankcase. Maybe moving air through is more important than the reduced pressure?

In the very long vacuum pump thread several hypotheses were generated for why vacuum pumps make power, but the consensus was that a lack of positive pressure permits better ring seal and seals the power generating combustion better. Then there were minor contribution from reduce windage (air friction reduce in a low pressure crankcase) and less air resistance to the down stroke of the piston. BTW I don't buy either of the last two--windage is more about oil and the pistons movement cancels each other out.

I'll work a little nipple off of the vacuum'd tubing and hook it up to my boost gauge to measure how much vacuum you maintain.

Thanks again for the attention.

OK, here is a better explanation of what we are doing and why (from my tuner):
There is a big breather tube coming off the block
That runs into a two way valve – one side goes to the intake manifold / one goes to the catch can
Under vacuum, the valve allows the intake manifold to keep vacuum on the crankcase (there is almost 0 blowby in this situation)
Under boost, the valve diverts the PCV to catch can which goes to the inlet pipe. At 20psi, a GT30 will suck your hand in if you aren’t careful – there is a lot of vacuum.

The valve breathers have no check valves and always go to the catch can and then intake. Off boost there is very little vacuum, but that’s fine. We’re looking to equalize pressure through the covers more than apply vacuum (as we do directly in the crankcase).

I'll work a little nipple off of the vacuum'd tubing and hook it up to my boost gauge to measure how much vacuum you maintain.

Thanks again for the attention.


Cool! Be scared if you see boost though :lol:

At 20psi, a GT30 will suck your hand in if you aren’t careful – there is a lot of vacuum.


Regardless if it's a GT40 or a VF22, I think most people will agree that it's a low pressure (vacuum) source. It's moving a lot of air but that doesn't mean that it's creating much vacuum to your catchcan.

I bet bboy has a good explanation for this as he's a science geek :D (I mean that in a good way).

OK, here is a better explanation of what we are doing and why (from my tuner):
There is a big breather tube coming off the block
That runs into a two way valve – one side goes to the intake manifold / one goes to the catch can
Under vacuum, the valve allows the intake manifold to keep vacuum on the crankcase (there is almost 0 blowby in this situation)
Under boost, the valve diverts the PCV to catch can which goes to the inlet pipe. At 20psi, a GT30 will suck your hand in if you aren’t careful – there is a lot of vacuum.

The valve breathers have no check valves and always go to the catch can and then intake. Off boost there is very little vacuum, but that’s fine. We’re looking to equalize pressure through the covers more than apply vacuum (as we do directly in the crankcase).
That's the same way the stock system works and the purpose of the PCV valve is to control the manifold versus venting into the turbo inlet.

We want to improve upon that evacuation AND not have the engine ingesting any oil through the intake. If I just don't want the oil bleeding into the intake, I can use a catch can alone.

I'm trying to take n2xlr8n's lead and do this:
http://www.competitionplus.com/09_17_2003/moroso_pump.html
with an electric vacuum pump.

edit: nvm

That's the same way the stock system works and the purpose of the PCV valve is to control the manifold versus venting into the turbo inlet.

We want to improve upon that evacuation AND not have the engine ingesting any oil through the intake. If I just don't want the oil bleeding into the intake, I can use a catch can alone.

I'm trying to take n2xlr8n's lead and do this:
http://www.competitionplus.com/09_17_2003/moroso_pump.html
with an electric vacuum pump.

OK, I see. All I care about is not having oil in the intake tract since I am running a blow-through now.

Yeah nobody likes det' inducing oil in the intake......except the EPA.

But what are we ultimately after...afterall? Aren't you guys modding your cars for more power/performance? Yes! Okay, so getting rid of the oil in the intake is positive to avoid oil caked piston tops/combustion chambers, which in turn can create detonation.

The idea here is to create vacuum in the crank case! This is what is helping the rings to seal. And, the end result is little to no caking of the combustion chamber. Simple!

But what are we ultimately after...afterall? Aren't you guys modding your cars for more power/performance? Yes! Okay, so getting rid of the oil in the intake is positive to avoid oil caked piston tops/combustion chambers, which in turn can create detonation.

The idea here is to create vacuum in the crank case! This is what is helping the rings to seal. And, the end result is little to no caking of the combustion chamber. Simple!

Don't forget that with a blow-through MAF, we need not to muck up the sensor with the oil vapor!

I'm trying to take n2xlr8n's lead and do this:
http://www.competitionplus.com/09_17_2003/moroso_pump.html
with an electric vacuum pump.

I'm with you....just not with that particular pump. Not a good idea, unless you have run one before, and you know exactly how to set them up.

The GM electric version is a no-brainer (and 20% of the cost) :)

S.

I'm trying to take n2xlr8n's lead and do this:
http://www.competitionplus.com/09_17_2003/moroso_pump.html
with an electric vacuum pump.

i can't believe they actually said:

Free from crankcase pressure, theoretically a piston on the downward compression stroke has less resistance to impede its progress, thus allowing it to accelerate faster.

ummm... how about when the piston's movement changes direction? :lol:

i can't believe they actually said:

ummm... how about when the piston's movement changes direction? :lol:


You'll have to convince me that what they are saying is not a valid point, Ken :)

The idea is to have as little pressure on the backside of the piston / rings during all 4 strokes. Regardless of the science behind it, when someone actually does the mod I've been preaching about, the interesting results will show

a) If a teardown is done. Note the combustion chamber cleanliness. The absence of crap on the plug is evident, as well. One thing I've noticed on these EJs is how nasty the combustion chamber/crowns are, even on a well-tuned engine.

b) On the dyno. Wagers? ;)

S.

well what i'm taking issue with is the idea that reducing the pressure on the bottom of the piston will cause an increase in torque output directly by virtue of the increase pressure ratio from "top" to "bottom" wrt the piston. maybe i read it wrong but to me it seemed like that's what they were saying...

i completely agree that there are a LOT of benefits of the having a high pressure ratio, but that's not one of them! you don't get something for nothing--every time the piston gets an "easier job" of moving downwards into an evacuated crankcase during a power stroke it has to do exactly the same amount of work giving it back on the exhaust stroke.

every time the piston gets an "easier job" of moving downwards into an evacuated crankcase during a power stroke it has to do exactly the same amount of work giving it back on the exhaust stroke.

I see what you're saying but I don't think it's that simple. The piston is designed to combust, and to combust, it has to move upwards (on the power stroke). On the other hand, it's not designed to pressurize the crankcase. It should work harder at moving upwards anyway (compression). It shouldn't have to work hard to move downwards.

It's true that there will be less resistance to any movement of the piston in a reduced atmosphere, but I think it's effect would be very small compared to the effects of friction from the cylinder walls, bearings, and oil viscosity.

The biggest benefit to me must come from having NO positive pressure in the crankcase with which to "flutter" the rings. Improve ring seal and you improve power transfer.

My plan is to try and document a boost from the GM vacuum pump by just turning it off while on the dyno. Even if it nets just 5 hp, it will be the cheapest power/$ mod going. If we can get anywhere near the "advertised" 5% it will be incredible.

I'm with you Steve, the Moroso pump poses a danger, requires much more fiddling, and saps some hp since it's belt driven. I'm hoping that the GM pump is big enough. I know it's designed for use on a much larger engine, but those are NA motors.

So the consensus is vacuum both vents on the block?

I'm hoping that the GM pump is big enough.

So the consensus is vacuum both vents on the block?


:p If it's big enough for a 9 liter, 1100hp monster, I think it will do on our EJ.


Not imo. I'm capping the valve cover vents, placing a filter on the forward CC vent, and pulling vacuum at the rearward baffled vent...you guys do it how you see fit. :)

S.

bump for an update bboy.

Ron told me to route my EJ22T/JDM V8 2 ports heads like this.

The 2 big ports on either heads are "T"'d together and then share a filter (small crankcase breather type), then the the 2 small ports are "T" with one of the passenger side CC vent (the one that faces the turbo) and that line goes to the air/oil separator. The other inlet for the air/oil separator is ran to the turbo inlet. The a/o sep. has a filter on top. I am confused what to do with the driver side cc vents. The PCV is hooked to the other hose on the passenger side CC vent.

Any thoughts opinions?

It's in and hooked up and awaiting it's trip to the dyno on 28th of April. I have the vacuum between the two CCVs and the oil-air separator (T connection for both vents, one hose to vacuum, one hose out of vacuum to o-a separator). The heads are also combined and plumbed into the oil-air separator. So the vacuum is only pulling on the crankcase vents and not the heads. Positive pressure into the o-a separator and then air comes out through the top.

I can tell you that there's more blow-by coming from the the big un-baffled one (driver side). Maybe not more per se, but it sure seems like it more of it since it's not baffled in the block. They both need vacuum IMO! To me it's not questionable. Try pulling that driver side vent hose off and rev your motor. You'll see what I'm talking about.


One is baffled, and the other is not; the "other" sits directly over the spinning crankshaft. I am pulling vacuum at the (rearward)"baffled vent".

S.

OK, here is my new concern. Now I'm worried a lot of oil is going to be coming out of the "driver's" CCV. Enough that I could suck a substantial amount of oil.

I have BOTH crankcase vents (CCV) hooked with a Tee, the third port on the Tee goes to the "in" of the vacuum pump.

I won't go into why I think this may be a problem, but suffice it to say it was messy.

n2xlr8n is pulling only on the "baffled" (passenger side, rearward). I don't see how I can do that without sealing the other CCV. Otherwise there will be no vacuum because the vacuum pump will just pull air out of the one CCV and air will rush in the other.

I'm beginning to think that the unbaffled, driver side (actually it's right in the middle of the block under the TB) is a SOURCE of oil for the heads. I cannot figure out why the STi designers would have made the PCV this way unless it's meant to push oil to the heads.

Is it possible that oil is meant to flow out of the CCV and into the two heads?

Hmmm....not sure bboy. Anything is possible I guess. With the baffles and seprators on mine (still tied to the intake) I'm not having any issues with oil. I know because I've got my IC pipes and intake off the car as I'm putting on new clamps right now. I had a slight trickle of oil at the intake but that's with 4k miles on the ODO. I say trickle because it wasn't caked in the inatke or turbo. Just a slight trickle in a stream. No biggie.

I had been running with the vacuum pump attached, but not runing. I had filled up the pump with some oil, so when I turned it on again I shot oil out of the pump's outlet. The pressure was high enough that it leaked past the hose attachment and coated my firewall with oil. Nothing a little degreaser can't handle. I'm toying with the idea of just plugging off the central (driver) CCV and pulling a vacuum on the rear (passenger) one. The nipple is larger, it's baffled, it's simpler, and that's what the PCV valve does anyway under no boost. Plus, I feel like once you are pulling a vacuum on the crankcase, it doesn't matter how many holes you are drawing air out of.

I'm going to call Steve and talk to him about the oil flow thing. I'm looking at this fubar'd system and for the life of me I can't figure out why the STI has an extra CCV and each head an extra vent. Why do that?

I was under the impression that the "pasenger" side CCV was supposed to be t'd to the two small head breathers in order to equalize pressure in the block. It's the large, "driver's" side CCV that has the PCV valve, in conjunction with the two large head breathers, that are supposed to do all the vacuum work.

There are separate oil passages to and from the heads, so no, I don't think the main CCV is supposed to play any role in pushing oil - at least I don't think it is supposed to.

There are separate oil passages to and from the heads, so no, I don't think the main CCV is supposed to play any role in pushing oil - at least I don't think it is supposed to.

Exactly.....whether it is supposed to or not, it seems like effectively the smaller vent does blow a lot of oil into the heads.

Drivers side=central=forward=under throttle body=5/8" OD
Passenger's side=rear=closer to firewall="PCV valve connection"=not under TB=3/4" OD

I think we are talking the same valve's Kirk, just opposite lingo.

Really starting to hate this system. Can't reach n2xlr8n yet, maybe tomorrow.

IMO, this is the best discussion I've seen on nasioc yet. A tremendous topic and filtered by serendipity because only knowledgeable, thoughtful folks are posting...

I'm sidelined again, but it gives me another opportunity to rethink my system. I've got that extra ccb filtered to atmo, and after giving it some thought, I think I'm going to do my valve cover breathers the same as Todd. However, I've still got my crankcase (the original Y'd breather) routed as it was in stock form. I'm just seeing too much blowby in my intercooler pipes.

If Steve sees this, I have no other reason than the fact that I'm a *****, but going the extra step and installing a vac pump just isn't in the cards.

....reading very carefully.

Thanks Pat, but I think we are all a bunch of gearheads fumbling in the dark. :) I know what you mean though, lot's of good folks including you.

For my Ventilation System du Jour we are serving:

Large baffled passenger side CCV to GM vacuum pump-->oil-air separator.
Smaller unbaffled "driver's side" CCV blocked off.
Cylinders heads are all hooked together like a big loop/circle: "in" driver's--"out" driver's-->"out" passenger's--> "in" passenger's-->"in" driver's (now we are full circle).
The only thing that is open off of the cylinder head circle is the small metal hose-end that would be connected to the "driver's" side CCV if I kept the stock routing. It's hard to get to, so I have left it open for now, but maybe later I'll put a hose and a little filter on there--or plug it.

So now, vacuum is being pulled all the time on the crankcase via the baffled passenger side CCV. Everything that could come out of the crankcase will go through the vacuum.

The cylinder heads are at "equal" pressure because they are linked togther and because the metal tube-end is open to atmosphere.

The block and the heads are at UNequal pressure by design. The vacuum pump makes sure that the block/crankcase is always under vacuum and therefore lower pressure than the heads.

It will probably stay like this until my dyno appointment unless I blow or suck a bunch of oil.

Todd was right. That one CCV (smaller one) moves a lot of oil. I don't want to deal with it, so it's capped off for now. Based on my extremely limited experience, I'd say that after 10 "pulls" from 3-8000 RPM in 4th gear I pumped 1/2-1 quart of oil out of the smaller/unbaffled/smaller/driver's side CCV. It's practically an oil pump!!!

-Trent

Drivers side=central=forward=under throttle body=5/8" OD
Passenger's side=rear=closer to firewall="PCV valve connection"=not under TB=3/4" OD

I think we are talking the same valve's Kirk, just opposite lingo.
OK, I'm with you now - I've been looking at the motor on an engine stand for do long now that I keep losing track of what forward is.

Let me ask you: do you think the reason why the smaller CCV is pushing oil is because you don't have the pump running yet so you are pressurizing the crankcase due to the routing? OR, do you think in one of the more stock configs it always sprays incidental oil up into the heads while acting as a pressure-equalization breather?

the more stock configs it always sprays incidental oil up into the heads while acting as a pressure-equalization breather

My guess, but I have not ruled out the blowby hypothesis.

Here is what I know. I finally hooked up the "forward/central/smaller/unbaffled" CCV and whammo lot's oil being pushed out. When it was hooked up as per the stock configuration, yes, there is some blowby oil, but not nearly the volume as after I Tee'd the two CCVs together.

It's still evolving. Feel like a total noob.

...Feel like a total noob.
Ditto. Put a lot of boost into a very small crankcase area with very large diameter pistons and, voila, you have the perfect recipe for crankcase pressure issues.

Other than a pump, it makes me want to tap about 2 extra low-end breather holes into this puppy.

Thanks Pat, but I think we are all a bunch of gearheads fumbling in the dark. :)

:lol:

I pumped 1/2-1 quart of oil out of the smaller/unbaffled/smaller/driver's side CCV. It's practically an oil pump!!!

Wow! That's pretty crazy. I almost want to cap mine off too. Although I'm not getting an oil surge like that (my oil/air separators must be working) I bet the one CCB on the pass-side of the block would suffice.

Yeah I agree guys, I'm finding the good threads to be fewer and further between these days concerning mechanical info. I just really wish there was more good threads on flashing the stock ECU...then I'd be in business ;)

I've taken the pump out of the loop. It's leaking oil on top of the transmission. I'm sick of the thing at this point.

I'm hooking the smaller/forward/unbaffled CCV up to the stock metal tubing that runs to the two heads (just like stock). It's basically an oil supply and too much blows out of there to use a vacuum pump on.

I'm hooking the larger/rear/baffled/passenger CCV to my oil-separator.

Phil Grabow is in town and I was talking to him about it. He designed the oil-air separator I'm using, so I asked him what he would do. He thinks, if I hook the vacuum pump to anything it will be to top of the oil-air separator. I'll do my best to find something to fit the top of the oil-air sep. by Friday when we throw it on the dyno.

A little advertising. I warn you it's pricey.
http://www.elementtuning.com/elementcompetitioncatchcan.htm

PCV is an interesting topic indeed. The hookup to the intake side of the turbo in my understanding is a great benefit to oil flow in the head. As crankcase pressure builds, it makes it more difficult for oil to flow up and into the heads (fighting the pressure). The pcv relieves this pressure and helps to draw oil up and onto the valvetrain. *Shrug* just my .02

So, what I call Loop 1 (forward CCB t'd to both small HB) is going back to stock, and you're going to vacuum the main CCB - so far, so good. What, if anything will now pull vacuum off the pre-tubo intake since, as I understand it, you have the manifold nipple (post-turbo) blocked? Or did I miss a T somewhere?

1. With this routing, how do you get any fresh air into the CC?
2. Is there a reason, in anyone's experience, why we shouldn't vent both loops, rather than just using Loop 1 to "equalize?"

(this frigging system is really starting to piss me off....)

The pcv relieves this pressure and helps to draw oil up and onto the valvetrain.
As long as Loop 1 is left in the stock configuration, any pressure differential is equalized quickly. The problem is Loop 2 is NOT very effective at reducing overall pressure. Therein lies the rub.

PCV is an interesting topic indeed. The hookup to the intake side of the turbo in my understanding is a great benefit to oil flow in the head. As crankcase pressure builds, it makes it more difficult for oil to flow up and into the heads (fighting the pressure). The pcv relieves this pressure and helps to draw oil up and onto the valvetrain. *Shrug* just my .02
Yes and no. The PCV creates an opening that "vacuums" the pressure built up while on boost in the crankcase. Like blowing into a beer bottle, you are quickly halted by air pressure, but the beer will slosh around quite easily (and oil will still flow into the heads). When the crankcase pressure gets higher than boost pressure, that's when the trouble begins. At that point the PCV valve get's forced open and oil starts spewing through it and into the intake.

So, what I call Loop 1 (forward CCB t'd to both small HB) is going back to stock, and you're going to vacuum the main CCB - so far, so good. What, if anything will now pull vacuum off the pre-tubo intake since, as I understand it, you have the manifold nipple (post-turbo) blocked? Or did I miss a T somewhere?

1. With this routing, how do you get any fresh air into the CC?
2. Is there a reason, in anyone's experience, why we shouldn't vent both loops, rather than just using Loop 1 to "equalize?"

(this frigging system is really starting to piss me off....)

Everything is back to the "stock" routing except:

1) No PCV valve.
2) The two lines that would have gone to the turbo inlet tube, now both go to the air-oil separator.

No PCV means no vacuum when off boost (vacuum supplied be the PCV valve and the manifold). So the crankcase is at atmospheric pressure all the time. As soon as blowby occurs it either goes into the two cylinder heads (through the unbaffled/forward/smaller CCV) or it goes out of the rear/baffled/larger CCV and into the OA-separator.

The two cylinder heads are linked together and are plumbed into the OA-separator as well (I've never seen a drop of oil out this hose).

More tuning today with this set up. I'll try to get the vacuum pump in line by friday when we check power numbers on the dyno. Trip to hardware store this morning turned up nada for an adaptor that will "suck" on the top of the OA-separator.

Very cool - let us know what you find out in the various configs. Curious minds need to know...

So I've run the last arrangement for few days. Phil Grabow and I tuned on on Tuesday and then after getting some larger water jets I tuned again on Thursday. In all I did at least 25-30 pulls in fourth gear from 2500-8000 over three days. I emptied the oil-air separator into a dixie cup and there was about a tablespoon of black watery gunk.

Now I need to watch oil comsumption and see if I'm burning any thing. The motor only has 3000 miles on it and I only burned any significant oil when I used 5-30 synthetic. Right now I'm using Mobil 1 15W-30. If I do see oil burning, then it's getting past the rings, but so far it looks good after 300 miles on the Mobile 1.

While on the dyno you could see the blowby coming out of the oil-air separator. Early pulls you could see a little soot come through the filter, and then later all you could see was the change in the air's diffraction as the hot gas was pushed out. It was cool to see it work. I have not seen any oil spray accumulation in the engine bay.

I still want to test out Steve's vacuum pump, but it will have to be in the future. I'll get something rigged up to draw on the top of the separator. The blowby gas is HOT; I'm not sure how well the GM pump will hold up long term.

I dont want my intake smeared with oily film. I have started to make arrangements for a large catch can mounted inside the front guard sort of under the ABS unit. I intend to run all 3 breathers (2 head breathers + rear block crandcase breather), directly to the can in 3 lines. Then initially vent the can to atmosphere but I intend to try the vacuum pump as well.
This will provide vacuum on all 3 breather points and create a negative pressure crankcase setup..

Till now I have had no connection to any of my breather fittings and I have no oil coming out yet. Its a new built motor with about 5000kms on it. I've got a dyno session coming up soon so I want the breather ready for that.

Any opionions/pitfalls to my suggested setup. Of course I only have 3 breathers on my ej20.

I dont want my intake smeared with oily film. I have started to make arrangements for a large catch can mounted inside the front guard sort of under the ABS unit. I intend to run all 3 breathers (2 head breathers + rear block crandcase breather), directly to the can in 3 lines. Then initially vent the can to atmosphere but I intend to try the vacuum pump as well.
This will provide vacuum on all 3 breather points and create a negative pressure crankcase setup..

Till now I have had no connection to any of my breather fittings and I have no oil coming out yet. Its a new built motor with about 5000kms on it. I've got a dyno session coming up soon so I want the breather ready for that.

Any opionions/pitfalls to my suggested setup. Of course I only have 3 breathers on my ej20.


So you've got: one block breather, and one breather on each valve cover? If so, then that would probably not be a good idea to tie in your block breather (it should vent) and the heads (they pull fresh air in for the block) - atleast that's how the manual shows the air/gas flow. This would mean that your heads would be recirculating the blow by gases from your block breather.

Yes, I agree with the post above only of you have something to suck the vapours out at the block breather and you want to ventilate the engine with fresh air. So if using a pcv valve (which I dont want), or the vacuum pump thats fine.
If your going for the "vacuum in the crankcase" setup with the vac pump I cant see any problem with running all the vents to one point, which is the catch can.

reviving an old conversation...

This thread totally helped me finish the plumbing on my hybrid and I am very interested to know if bboy ever got the pump fixed to the top of the AO separator. There was no resolution to solve this dilemma. You guys are killing me with anticipation. Definitely one of the top five best ever threads on here.