You know.. I must have been half asleep when I posted all that stuff about my install of the headers and cooling system.

The most important thought I had and I forgot to make note of it.

As you know all these new generation cars have EGR (Exhaust Gas Recirculation) valves/systems in place to help reduce the level of emissions. There are tubes that run from the crankcase to the intake tract (please anyone correct me if I am wrong on this explanation).

Because of where these tubes are, they will pick up oil from the crankcase and recirculate it back into the intake system (throttle body). This gets injested/burned by your engine.

Now, over time, this oil will harden and form sludge around your pistons and other internal engine parts. If you've ever taken off your Y shaped intake tube that runs from the air boxes to your throttle body, you would know what I am talking about.

Oil injested by the engine will cause a decrease in octane and could lead to knock or timing being pulled. There are a few ways to combat this.. One is to put an inline filter in the tubes to trap any oil before it enters the throttle body. This option, while effective, would require you to periodically empty the little trap where the oil is. The second option is to purchase an oil catch can. It is the same idea except that it will hold a good amount of oil and has level indicators telling you when it is time to empty them.

Now, saying all this, I have ordered one of these: http://www.machv.com/groilcacan.html to put inline on the EGR hose to stop oil from being fed back into my engine. There is lots of room on the backside of the engine firewall to mount one out of sight.. I will be playing with placement to try and hide it as best as possible.

This issue will be of increasing importance as you increase the horsepower of your car.

As always, I will be sure to take lots of pictures during the install.

Just thought I would share this thought..

Nice write up on the mods. I can't wait to see the performance numbers. Interesting that MB didn't put any kind of a filter on the breather tubes. Even a sponge would work.

BTW, oil in the combustion chamber does not reduce octane, it increases your octane requirement! I know, I'm nit picking. Sorry. I just can't help it sometimes.

Semantics... You are correct though.. Thanks for making that point.

vrus - Your idea is a good one, however you have removed the Exhaust Gas Recirculation capability of the system (I am assuming that you are not going to hook the EGR line back up to the Intake System, instead venting it to atmosphere). What you can do, is run a line from the new oil Catch Can back to the intake system and that would keep the EGR system in-tact. The major problem with all Catch Can systems is the oil, that is carried in the air, and sucked out of the crank case area, has been atomized into such a fine mist that it is very diffucult to separate it from the air, so any attempt at trying to capture this fine oil mist would have to involve some sort of filtering material for the oil to cling to, thus being separated from the air. The Catch Can you have chosen may not have any filter material in it. However, it does appear that the top can be removed for access to the inside of the Catch Can, allowing filter material to be put inside. Also, you would have to make sure that the intake tube goes to the bottom of the Catch Can and the outlet tube is flush with the inside of the Catch Can top, to force all the gases to go thru all the filter material before exiting the Catch Can. All this assumes that the EGR system is still being hooked back up to the intake system. Keep up the good work! - Bob

Nope.. You missed it... Look at the pic of the catch can carefully..

It has an line going IN and one going OUT. The EGR system will remain intact.. This is how it will get hooked up:

- Disconnect hose from crankcase to throttle body at the throttle body. Connect it to the Catch can.
- Connect another hose between the other side of catch can and the throttle body.

This will take the gases that are in the crankcase and carry them to the oil catch can. Since oil is heavier than air the oil will drop to the bottom of the can once the vapours enter the can. The air will then continue through the other side of the catch can into the output hose and move towards the throttle body.

So, as the vapours pass through the can, the oil gets left behind and hopefully 100% clean air continues on into the throttle body.

I've done this on past cars and it is remarkable how much oil gets trapped in there.

I'll post some pics of what gets caught in there after a week of driving and at that point might shock a few people.

Where is the line that recirculates the gases and where do you plan to install the catch can?

I am pretty sure it is the line at the back of the block right behind the throttle body opening of the supercharger... It runs under the area where the air boxes are.

I think there is 1 line on each side but not 100% positive. I need to look it up in the shop manual CD and see exactly where they are and if I need 1 or 2 of those catch cans.

I am going to try and mount it at the rear of the firewall.. Not sure of exact location yet.. Have to play around with different mounting points until I find something that works.. It needs to be fairly easy to get to and to remove because it will have to be emptied every couple of weeks.

Could you mean PCV (Positive Crankcase Ventilation) and not EGR (Exhaust Gas Recirculation)? The recirculated exhaust gas is supposed to mix with the fuel/air mixture and has the purpose of lowering the temperature of the exhaust, thus creating a lowered level of NOx (Oxides of Nitrogen). Right?

:p Yeah... Damnit.. of course.. I mean PCV!

Thanks for the correction.. But, you get what I mean...

Victor - Please allow me to clarify:

What you have described here is the PCV system (Positive Crankcase Ventilation). Its intended use is to remove blowby gasses (essentially unburned fuel - ie, hydrocarbons) from the crankcase before they can contaminate the oil. The PCV valve is essentially a check valve that only allows flow from the crankcase to the intake.

The EGR system is used to reduce the amount of NOx created by the engine. It does this by diluting the air/fuel mixture with a small amount of exhaust gas. Since exhaust gas has virtually no O2, it is fairly inert. Adding it has the effect of lowering the combustion temperature below the point at which nitrogen combines with oxygen to form NOx. The EGR is usually active during cruise mode - not during idle, WOT, or when the engine's cold. There should be a tube running from the exhaust manifold to the intake somewhere that contains the EGR valve.

Yup. Thanks for the input. I realized I used the wrong acronym right after I read CanDrive55's post.

The E55 has 2 EGR valves at the front of the supercharger.. They kind of look like bypass valves but later found out are for the EGR system.

The PCV (as you and CanDrive55) pointed out is what I was trying to refer to.. I have to double check the location but I think I know which hoses they are.. just a matter of confirming it with the WOrkshop Manual CD.

Thanks to both of you for the correction.. Last thing I want is people to read this stuff and be even more confused.

I only hope I got my idea across to those that read it...

Another nice write up. You get into the technicals behind these cars. I'm so scared to mess with much, until the warranty runs out.

Well.. it's easier than I thought. The PCV hose runs from the crankcase into the hard rubber Y-shaped intake tube on the back of the throttlebody. Its on the driver's side..

I will pick up the catch can and do an install and post some pics.. Hopefully in a few days I'll have some evidence in there to show all of you.


Jangy: Thanks. I like tinkering...

vrus - I agree that some of the oil will be left in the Catch Can and will do so, in-part, because of a temperature drop as the Air/Oil mixtures travels thru the hoses and the new Catch Can. Don't forget that the oil mist made the trip to the Catch Can because it was suspended in the air in the first place. True, oil is heavier than air when in liquid form, however the oil mist is not and that is why it makes it all the way back to the Intake System and the top end of the Motor.

My suggestion, filling the Catch Can with a open filter material, will increase the surface area the oil mist comes in contact with and will promote the mechanical removal of the oil mist from the air, which is the last way, besides temperature drop, that will remove the oil from the air.

In any case, not all the oil will be removed, however any oil that is removed is a plus for performance.

Again I appreciate all your efforts in documenting the changes and the resulting changes in performance. - Bob

This is a good idea, Vrus. If you decide to try it, steel wool would be a good material to promote oil condensation. Plus, it's cheap.

If steel wool is so good, why don't auto manufacturers use it? They use foam or a more open weave plastic material similar to Scotchbrite in factory PCV systems.

After doing a bit of research (and not being able to find the Greddy unit in stock ANYWHERE), I decided to order one of these instead:

http://www.accmachtech.com/pcvcatchcans.htm

They are a bit pricey but they are the best from what I have gathered.

Evolution Marine:

I agree with what you are saying and I would suspect that if the in and out passages were in a direct flow pattern I would be worried, but, since the entry and exit points were different I figured most if not all of the oil would be trapped.

In any case, this new unit that I found actually has a filter mesh of some sort which helps to keep the oil at the bottom of the unit.

I should have it in a couple of days and will take some nice pictures..

vrus - Now thats a Catch Can! Great design! Maybe I am just a succer for good engineering but the price seems very fair to me. I would check the oil level to make sure that it does not get up to and in contact with the SS Screen, other than that, you have made a good choice. - Bob

Thanks!

Yeah. I am a sucker for great engineering also.. That's why I dont mind spending the money on it.. but a couple of guys called me crazy when I told them how much the catch can was...

I try to buy the best stuff and hopefully get it right the first time.. More expensive upfront but cheaper in the long run.

Should have it in a couple of days and will install same night I get it.

My guess would be the same answer that is used for all questions of this type - cost. The OEM units are designed to be throw-aways and would probably not survive the cleaning chemicals. If you check out the unit that vrus purchased, you'll see that they use stainless steel mesh for the condensing material.

Yes. Thanks for that. After I read your comment I started looking for some alternatives with a steel filter and that's what led me to the AMW catch can.

Makes sense. The OEM units are typically service items that get tossed.

Be careful not to introduce any restrictions in the system that would impede the return line to the intake side of the engine. On FI cars any restriction can lead to inadequate venting of excess pressures. Longterm result of this is springing oil leaks around your oil pan from sustained overpressurization of the crankcase. The overpressure is from blow-by around the piston rings (on our new cars with low boost it should be minimal). I think the ratio for crankcase ventilation requirement is double per every additional 3psi of boost. Also, ball-checkvalve systems tend not to work too well in that they cannot react quickly enough to the pressure changes. Some systems even include a return line to the crankcase so you don't even have to worry about draining the catch-can.

Hmm.. Interesting... I've seen these particular cans working on high boost, high horsepower cars but not specifically an E55... From my point of view our cars run HIGH boost.. We are at 12lbs which is quite a bit.

Heck, a 5.7L LS1 motor which is 350hp from the factory goes to 460rwhp with a 5psi Magnuson supercharger. Consider we have more than twice the boost and we only manage 420rwhp stock... That's a pretty significant difference.

I'm a bit nervous about inadvertantly pressurizing the crankcase.. They say to install a small one-way check valve to be safe.. not sure what that is or what part I should use...

Any suggestions on how I can test if this is becoming a restriction? I just want to stop oil from being sucked into my engine..

Unfortunately restrictions usually will manifest as a oil leak or multiple oil leaks. Many in the Subi/Porsche/Evo worlds would have found out the hard way that venting to atmosphere will even lead to oil leaks from inadequate ventilation. The suction of the intake tract is negative pressure which helps to evacuate the crank pressure much more effectively than just venting thru a atmospheric breather filter like a hot rod. As long has you have a catch can/oil trap there should be no danger in sucking excessive oil into the intake when plumbing the line without a check valve.