[EastBayE90]

I'm assuming by the picture you posted from the N54 tech PDF that the check valve would be located near the top right corner of valve cover in that picture.

Here is another picture I found and on ALLDATA for 1 it says

Detach crankcase breather (1) at cylinder head cover.



Uploaded with ImageShack.us

So the lower line is a breather also? I thought the bigger fitting just above 1 was the PCV line.


EDIT: looking at this new picture the PCV block seems to sit directly ontop of the valve cover hence why we would not see it in my first picture. But if you look at the first picture on the inside of the valve cover you can see two square holes and that is probably where the PCV block sits.

[marconi118]

looking on the picture of post 122 under the line that comes from number 3 there is this horizontal cylinder. The right end (back of the car) is closed with a round cap that you can simply unscrew.

Inside there is in the centre a small 6mm round passage that goes to the intake valves (it splits into 6 somewhere in the head). I closed this hole with a piece of silicone hose and a crew.

running this since several months, no issue, no oil leak of the cover seal and a lot of blow by because now all the "shit" is going out via the catch can (actually I vent it to the atmosphere at the back of the car via a 22mm pipe, it smells like a shit for the others behind me )

[EastBayE90]

This is word for word from ALLDATA for the explination of the PCV system






Engine Ventilation
The engine ventilation is pressure-controlled. Depending on the intake pipe partial vacuum and charge-air pressure, venting takes place either via a 6-way distributor rail in the inlet ports or into the fresh air pipe before the exhaust turbocharger (cylinders 4 to 6). The distributor rail is integrated in the cylinder head cover.


Two valves are fitted for engine ventilation.
Non-return valve with pressure limitation The non-return valve with pressure limitation regulates the flow depending on the applied intake pipe partial vacuum and controls the introduction of the blow-by gases into the inlet ports.
As of a defined charge-air pressure, the non-return valve closes with pressure limitation.

Non-return valve to the fresh air pipe The 2 fresh air pipes are arranged after the intake muffler. Each of the 2 fresh air pipes connects the air filter to an exhaust turbocharger. In the fresh air pipe, the air cleaned in the air filter is transported to the compressor.
As of a defined charge-air pressure, the prevailing partial vacuum in the fresh air pipe opens the non-return valve. The blow-by gases are vented into the fresh air pipe to the exhaust turbocharger (cylinders 4 to 6).
The ventilation connection to the fresh air pipe has an engine ventilation heating system based on the PTC principle (positive temperature coefficient). The engine ventilation heating is activated via terminal 87.

[Joshboody]

Originally Posted by marconi118

The "secondary valve" is in the valve cover next to where the OCC connects, there is a small round cover you can remove by unscrewing it with a flat key. I obstructed this valve with a simple piece of silicone pipe, so that no blow by will go directly in the manifold and coat the valves....

that's bold, but maybe semi-ok. this would leave the boosted side open, since the off boost side closes the boosted side check valve with vacuum i'm assuming. BUT boosted side would be working on less, or no vacuum at cruise and idle. Your cc pressure has to be higher with this setup. And then a OCC would compound this.

[Big Tom]

Originally Posted by RobBeck

That Big Tom catch can appears to be the fire!! Good job!! (I want one!!)

But, you need to get that check valve back in there. Its needed as when the intake manifold (post throttle body blade) is lower vacuum than pre-throttle blade... The secondary check valve opens and that one is supposed to close. So in essence you are creating some sort of vacuum leak at idle and ver low loads without that check valve in place. Aside for that, looks amazing.

As for the secondary check valve, it's supposed to close when the post TB blade pressure is higher than the pre-TB blade pressures (ie. Under boost and mild engine loads). At this point the check valve you ommited is to open and is essentially what you have in your setup.

Can anyone locate this secondary valve? It's in the diagrams but I havent had a moment to tear my car down to find it. I have concerns it may need replacement after time, and if it leaks under boost it will cause the turbos to pressurize the crankcase.

Ok, so you're saying that I should re-install the check valve?
In that case, it's a 5 minute job.

[dzenno]

Originally Posted by Big Tom

Ok, so you're saying that I should re-install the check valve?
In that case, it's a 5 minute job.

I definitely would...

[Big Tom]

Originally Posted by dzenno

I definitely would...

Ok sir, I will.

Pics will come.

[cn555ic]

Originally Posted by Big Tom

Ok, so you're saying that I should re-install the check valve?
In that case, it's a 5 minute job.

yes I would...also please give info of the BIG TOM Catch can...where to buy and materials needed!!

[dzenno]

Originally Posted by Joshboody

that's bold, but maybe semi-ok. this would leave the boosted side open, since the off boost side closes the boosted side check valve with vacuum i'm assuming. BUT boosted side would be working on less, or no vacuum at cruise and idle. Your cc pressure has to be higher with this setup. And then a OCC would compound this.

hmmmmm let me get this straight...the checkvalve marconi capped off, now when his car is under boost air is being pressurized by the turbos into the intake manifold and has no way (in case of say that checkvalve going bad, being clogged or just capped off as what he's done) of entering back into the crankcase. This is GREAT in eliminating additional crankcase pressurization due to boost from that side and solves the "on boost" part of the equation. The other checkvalve (the one OCCs are hooked up on) will be open under boost and vent to whatever you're running attached to it (breather or an OCC or back to the rear intake pipe)...That solves the acceleration/boost issue as now you're doing 2 things perfectly: 1) not pressurizing the crankcase under boost and risking damage to your engine seals and turbo seals and 2) not letting vacuum in the intake manifold pull out oil vapours from the engine and clog up (carbonize) your intake valves.

Then if we look at what happens under decel/cruise/idle though (which is what the car sees vast majority of the time unless its a dedicated race car)...the checkvalve we capped off will obviously remain closed so any built up crankcase pressure during our onboost run will not vent using vacuum in the intake manifold when on decel/cruise/idle...the other way out (other checkvalve) will also be closed under decel/cruise/idle because the PCV outlet checkvalve that goes out to the OCC or rear intake pipe will be closed as vacuum has closed it (not a very tight seal as I've noticed yesterday by blowing air from my mouth through it) ...UNLESS...you remove that checkvalve!

So with the latest Big Tom setup (no checkvalve) and the other checkvalve that closes to the intake manifold capped off as marconi indicated we should actually be all good...

a vacuum pump at the crankcase outlet on top of that would totally complete the picture (triggered when the car goes into vacuum) but I'm not sure how complicated that'd be to setup/configure..

what do you guys think?

[Joshboody]

yeah, taking the check valve off would be better in this case. A vacuum pump would be really cool, then you can use a heavy duty, restrictive oil/air separator. I'd pay $500 bucks for this and a plug for blocking the one valve.

In the diagram it looks like the boosted check valve is in the head cover and the removable hose maybe a secondary check valve??

[dzenno]

Originally Posted by Joshboody

yeah, taking the check valve off would be better in this case. A vacuum pump would be really cool, then you can use a heavy duty, restrictive oil/air separator. I'd pay $500 bucks for this and a plug for blocking the one valve.

In the diagram it looks like the boosted check valve is in the head cover and the removable hose maybe a secondary check valve??

Vacuum pump would be awesome but I've also read that there's only so much vacuum (their measurements were in inches when I was reading it) you should ever pull on the crankcase...not more, not less...this is why I wouldn't know how much is good enough and not too much...hmmm, what would be test best setup for this part of it I wonder...

You're right about the diagram...marconi seems to indicate that its possible to get to the intake manifold checkvalve without taking the valve cover off...i'll check that Saturday when I actually get to work on it a bit..

[Joshboody]

Originally Posted by dzenno

Vacuum pump would be awesome but I've also read that there's only so much vacuum (their measurements were in inches when I was reading it) you should ever pull on the crankcase...not more, not less...this is why I wouldn't know how much is good enough and not too much...hmmm, what would be test best setup for this part of it I wonder...

You're right about the diagram...marconi seems to indicate that its possible to get to the intake manifold checkvalve without taking the valve cover off...i'll check that Saturday when I actually get to work on it a bit..

agreed on the amount of vacuum, but a company could easily test this and be able to sell a very nice system. max manifold measurement and some calculations based on the restrictor would be a good start.

[dzenno]

Originally Posted by Joshboody

agreed on the amount of vacuum, but a company could easily test this and be able to sell a very nice system. max manifold measurement and some calculations based on the restrictor would be a good start.

Alright, so, "companies", who's up to the job to offer this solution for us high boost junkies?

Thought I'd share this as well:

http://nutterracingengines.com/racin...uum_facts.html

[dzenno]

Take a look at this:

http://forums.bimmerforums.com/forum...d.php?t=995302


Heres what I designed for my electric crankcase evacuation system. For boosted Apps It is programable to come on from 1-30 psi of boost. It's going on my 402@15psi. It fits in the stock battery tray. My battery is going in the rear compatment like the Z06


ELECTRIC CRANKCASE EVACUATION SYSTEM
Apply a vacuum source to the crankcase. Rather than putting a breather on the valve cover to let crankcase pressure out, pull the air out with a pump to create a vacuum.
Benefits of Negative Crankcase Pressure using an Electric Pump:

1) Prevents oil leaks from seals and gaskets by eliminating crankcase pressure.
2) Reduces parasitic losses from pistons pumping against crankcase air.
3) Improves piston ring seal.
4) Increases HP and makes your engine last longer.
5) Eliminates your PCV system and the possibility of oil being sucked into your engine keeping your intake system and combustion chambers clean.
6) Eliminates the need for mechanical belt driven evacuation pump that robs some HP and needs rebuilding frequently.
7) Superior to valve cover breathers and exhaust path suction type pcv systems which contaminate your exhaust system and mufflers with oil.
8) Pump can be set up with the filtered crankcase exhaust routed to air filter housing instead of out to breather if desired for a closed loop system (emission friendly).
9) Fits in factory battery tray for easy access to engine. (Battery must be relocated to trunk or rear compartment).
10) Ideal for Turbo, Supercharged and high compression engines which create higher crankcase pressures at high RPM’s/Loads.
11) Creates 5 inches of vacuum in your crankcase with a very high CFM air flow when needed at high RPM’s, exhausting and filtering all blowby, while still maintaining its vacuum for ring seal.
12) The waste oil level is easily seen through sight hose and drained through a valve on the side of catch can. If any oil vapors pass the modified Catch can, they will be condensed and caught in the Air Dryer before reaching the pump to ensure long pump life.

[dzenno]

Another interesting article on vacuum pump assisted crankcase ventilation from the Supra forums, pasting over here (http://www.supraforums.com/forum/sho...se-Ventilation) :

Vacuum for Crankcase Ventilation
All cars have combustion gases blow pass the rings into the crankcase. In the old days, Breathers on top of the engine vented the excess gas, more or less keeping the crankcase at atmospheric pressure. Racecars had really big vents. Turbocharged cars could blow even more gases past the rings. However with combustion pressures of 10 atmospheres, all engines do it.

For emissions reasons, the gas was recirculated, drawn by intake vacuum through a check valve. On the Supra, the system has two check valves, and vents into the intake on either side of the turbo depending on the boost level. Rather small tubes though.

On this board are stories of front seal failures...a sign of an over pressurized crankcase. There are also pictures of very small filters on the end of small tubes; can they have enough capacity for a 600hp 3 liter? And there are configurations with those tubes vented to a tank, and then to the intake. Can than create enough pressure to draw excess gases through that circuitous route?

In oval racing there is a story (told as having happened at Stef's), where an engine was dyno'd, but they didn't have the right valve covers. So they put on some covers that didn't have breathers installed yet. When they put on the covers with breathers, the HP went down. When they put the closed covers on, the power went up.

This engine had a dry sump system. The dry sump positively scavenged the air in the crankcase. When it had the sealed covers it created a vacuum, and that raised HP.

In NASCAR today, engines run with around 20-psi vacuum in the crankcase. Dry sump pumps have their scavenge sections designed to create vacuum. A check valve is added to suck air into the crankcase to prevent excess vacuum. In lower racing classes, my dry sumped late model is limited by the rules to 2 scavenge stages, limiting the amount of vacuum.

Virtually no one dry sumps the Supra. Owners have found the stock wet sump adequate for road racing, drag racing, and who knows what else. However, would a vacuum pump help?

These pumps are a single, large vacuum stage off of a dry sump pump. It could scavange the air into a surge tank that vented to the intake. If the tank was baffled, presumably oil would separate and only air and gases would return to the intake.

ATI lists a damper with a dry sump pump adapter. My search has not found any pumps or mounting kits. And it looks like a tight fit around the engine.

Has anyone successfully mounted a vacuum pump to the Supra?

Thanks,

David

P.S.
This a link to Moroso's vacuum pump catalog page

[dzenno]

Here's a link to the Moroso racing vacuum crankcase evac pumps:

http://www.moroso.com/catalog/catego...?catcode=17200

How would we hook one of these in?

[EastBayE90]

Originally Posted by dzenno

Take a look at this:

WOW is all I have to say. That is impressive. Someone did his homework.

[dzenno]

Researching further on this topic on other turbo platforms (vw/audi) seem to suggest that vacuum provided by the turbo (so in our case the rear intake tube where the stock PCV hooks onto) is a great source of vacuum and basically a free vacuum pump every turbo car comes with

In any case this PCV on the N54 definitely needs some research/testing especially as we run high boost/upgraded turbos...crankcase pressure gets really evil up there and if at the minimum the stock checkvalves aren't working as they should it can wreak havoc in various places

[Rob@RBTurbo]

Yeah if that check valve "3" pressure restrictor is up to the task (even after mileage) I'd be inclined to just go the big tom route but with the check valve installed.

[Ilma]

Originally Posted by dzenno

Researching further on this topic on other turbo platforms (vw/audi) seem to suggest that vacuum provided by the turbo (so in our case the rear intake tube where the stock PCV hooks onto) is a great source of vacuum and basically a free vacuum pump every turbo car comes with

In any case this PCV on the N54 definitely needs some research/testing especially as we run high boost/upgraded turbos...crankcase pressure gets really evil up there and if at the minimum the stock checkvalves aren't working as they should it can wreak havoc in various places

That was one of the weaknesses in the VW/Audi platform.
The stock pcv system could not handle the additional boost from tunes and would allow some leakage and blowby into the crankcase.

You could easily spot it by looking at your oil filler cap......if the oil on the cap looked frothy, it was a sign that your boost was entering the crankcase. Sometimes it would even leak around the oil filler cap.

Dzenno, if you have the BSH catch can, you should contact Phil @ BSH as he did a lot of work fortifying the VW PCV system and came out with some useful bolt on kits that made sure boost didn't enter the crank and that there was still a vacuum source during idle/deceleration cycles.

[dzenno]

Originally Posted by Ilma

That was one of the weaknesses in the VW/Audi platform.
The stock pcv system could not handle the additional boost from tunes and would allow some leakage and blowby into the crankcase.

You could easily spot it by looking at your oil filler cap......if the oil on the cap looked frothy, it was a sign that your boost was entering the crankcase. Sometimes it would even leak around the oil filler cap.

Dzenno, if you have the BSH catch can, you should contact Phil @ BSH as he did a lot of work fortifying the VW PCV system and came out with some useful bolt on kits that made sure boost didn't enter the crank and that there was still a vacuum source during idle/deceleration cycles.

Yeah, I notice a lot of discussion on this topic on vw/audi forums around their PVC setups and failures around checkvalves...

If you have Phil's contact info please pm it to me..i'll call him..

EDIT: Sent BSH a message through their site describing the issue, awaiting response. Found this on their site which they've done for the VW engines: http://www.bshspeedshop.com/bshstore...CV-Revamp.html

[Big Tom]

Crap... It's impossible to get the checkvalve to fit with my OCC. There's simply not enough space between the engine and the fire wall.

I ended up with re-installing the stock PCV system again... The history continues.