Catch-can Vs. Nismo separator Vs. Oil baffle

[cobrAA]

Hey guys,

I'm on my last few bit of my grocery list and I'm not sure if I'm doing it right.


Right now I have a basic catch can vented to atmo + PCV removed. I then bought the Mine's cam baffle.

Problem is that the catch-can vented to atmo 1) take place in the already cramped engine bay 2) my engine bay is misted with oil .. not sure its a good thing for the air filter lol..

So I'm thinking... shouldn't I be running this instead ? http://www.hioctanedirect.com/index....oducts_id=1636

This item would eliminate the problem I have with the catch-can.

Or to be optimal, I should be running all 3 ( catch-can + cam baffle + oil separator) ?

thank you!

[caliber676]

There's always going to be mixed ideas on the subject. The way I'm doing it is cam baffles with an oil separator plumbed back into the intake. Some people say that mines cam baffles hold too much pressure and blow by in the engine, but with regular oil changes I don't see a problem and a reputable company like that isn't making useless parts. The nismo separator has the correct system which you could also make yourself. Basically they are using an oil separator off the valve covers with the collected oil sent to a catch can and oil vapors sent to the intake, and adding cam baffles is what I would do.

At the end of the day any closed Pcv system will circulate some oil into the intake, it's ok, people lose there pants over it though. I've seen it on R8 gt's and rs7's, if it's ok for them, it's ok for ours. You don't want pools of oil in your piping but some misting is inevitable. I find it silly to be venting a system to atmosphere just to avoid some oil mist when you can properly use a closed system and maintain a crankcase vacuum which is beneficial in all aspects

[Bruizer]

The difference is about $100-200. I have the nismo air oil separator if you want it. It's used. I'm going back to a catch can cause I don't want nismo parts.

[r32_nate]

So im curious in reading this, and sorry if I jack ur thread OP. I was running with my PCV still in, vented to atmos (we have no restrictions for that **** here in NB). So when I rebuild this time, is this gonna cuase issues for me? I see people who remove them and use catch cans and all the ****, but I was just planning and letting it blow out for the world to see lol.

[bobbo]

Cam baffles and Nismo seperater is my vote. Baffles being redundant perhaps.

[Skym]

There's alot of pressure in the sump due to excessive blowby at higher rpm, which causes the oil not to return to the sump (blocks the oil returns) and forces the oil out the camcovers.

The key to a good catch can setup is to relieve this sump pressure which normally goes through the small oil galleries in the engine and to the camcovers and then into the intake. Gets worse if you restrict the oil galleries with oil restrictors.

One way to do this is to bypass the small oil galleries via running a few hoses to catch can from the sump (need to weld on fittings to the sump). This is done on R34 N1 GTR's, which also use a V8 swinging pickup setup.

On dry sump setups the multiple stage pump draws the pressure out of the engine, sump. With stock PCV setup the intake of the engine becomes the multi stage dry sump pump.

With venting catch can to atmosphere the air running under the car at higher speeds becomes the pump, hence why the vent hose from the catchcan is vented just behind engine on some racecars.

You need a pump source whether it intake, exhaust (with a one way check valve) or air running under the car.

To remove as much oil as possible before going into intake or whatever pump source you are using, you run it through multiple oil separators / catch tanks.

Also on R33 JGTCC cars with RB28? they ran R33 RB25DET camcovers, as the breathers are in a better location. There was many photo's of this setup on the net.

The problem is the more boost you run, the higher the pressure and the more oil is pushed out the camcovers. There's a point where a dry sump setup is the only option / fix for oil starvation, blowby related issues. Many have learnt this the hardway.

[leung23c]

Firstly, I am no expert. In fact I am a noob. I just read a lot and summarize what people say and process them through my brain. So take my comment consciously. Here is what I believe:

The biggest problem is ring gap........

Secondly....

The problem is the pressure in crankcase is higher than the pressure in the head, so when the oil wants to return to the sump thru internal galleries, it need to move against the pressure differences (sump higher than head, remember).

The head drain kit that connect the back of the head to the top of the sump acts as a pressure equalizer, letting the oil gallery to do their job to let oil fall back into the sump, not necessarily letting oil to fall back from the back of the head back to the sump. This is what I will be doing anyway.

The ideal way is connect the crankcase and head to catch can/breather separately. But most people can't....

Thirdly, vent the catch-can to exhaust pipe through something like this:

http://vibrantperformance.com/catalog/product_info.php?cPath=1022_1069&products_id=1243

Fourthly, install a Mine's cam baffle or hi-octane one, to retain oil in the engine.

Read Hi-octane, lewisengines.au, RIPS N.Z., gtr.co.uk, SAU, whatever.

[cobrAA]

I sent an email to Hi-octane. here's was their replies:

Hi

I would use all 3 together

The more the better for the GTR and they breath heavily

Venting the crankcase is also good

Regards,
Kyle Major
Sales/Manager.