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Lesson learned about crank case ventlation breather

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Old 04-17-08, 04:12 PM
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Lesson learned about crank case ventlation breather

So I learned today that it is not wise to use a restrictive filter as a breather, as it turns out it finds other ways to push the oil out....like my rear main that used to leave a drop or two...it now dumps a cup full on the driveway.
I was tired of oil being sprayed from the bigger oil type filter (k+n) knockoff I had been runing for years, now I get it out the rear lol.

I finally just grabbed a jug and ran a open tube to it....no more oil problems-just a getto engine bay for now.
Old 04-17-08, 04:15 PM
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you can buy a decent catch can on ebay for like 20 bucks they look and work alot better then a jug lol
Old 04-18-08, 05:37 AM
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I was just thinking, doesn't the cold start tank have two nipple on the top? It ought to make a swell catch can... I might have to do that especially with a vacant engine bay at the moment.
Old 04-18-08, 12:27 PM
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I switched from an open filter on the top of the oil filler neck to catch above the clutch slave on the firewall when I started auto-xing. I just used a tall alum. JDM beverage can with holes slit in the top of the lid.

Its Blue (5hp) and everybody knows Kanji add 10hp and Kana anoth3r 20hp because they are even more JDM as Chinese junk has Kanji too, but no Kana.

Sustained Gs were just causing too much oil to back out the filter during slosh- you can tell when it is going to happen because the oil level sensor has been going off during your run (yes, RB baffle in place).

The 2 gallon flat sided comp. oil pan REALLTY helps with the level sensor issue BTW

There was also an incident where the filter accidentally got pushed onto its hose too far and closed the end of the hose and almost took out my turbo rear oil seal!

Luckily after a few days of smoke screen the seal reseated itself when I temporarily ran vacuum to the sump.
Old 04-18-08, 01:52 PM
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you don't need a catch can if you dont want... you can just run vac line or something to the nipples and zip tie them to the fuel hardlines...(thanks REted)
Old 04-18-08, 02:40 PM
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the oil catch can is for the charcoal canister removal, correct? i dont understand this mod, how does removing the charcoal canister and replacing a catch can help at all? i removed emission twice but always left the top nipple on the filler neck run to the CC....
Old 04-18-08, 02:44 PM
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Originally Posted by lastphaseofthis
the oil catch can is for the charcoal canister removal, correct? i dont understand this mod, how does removing the charcoal canister and replacing a catch can help at all? i removed emission twice but always left the top nipple on the filler neck run to the CC....

YOU DON'T UNDERSTAND ALOT.!
Old 04-18-08, 02:52 PM
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ok, so what, is my charcoal canister full of oil? or what , it's kinda why i asked....
Old 04-18-08, 02:54 PM
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Originally Posted by lastphaseofthis
the oil catch can is for the charcoal canister removal, correct?
No.
Old 04-18-08, 03:09 PM
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The problem with putting the sump under intake vacuum is that you suck all the sloshed AND misted oil right into your engine.

I had this set up first with a cotton gauze and steel wool packed oil/air seperator at the highest point of the engine bay before the vacuum. The separator would work on the mist, but as soon as oil sloshed from cornering the thing would fill with oil.

You suck in oil after a hard corner when you get back on the gas and blow your motor.

After taking apart that engine and seeing all the oil in the front (blown) runner I took off the vacuum line.

You can put a vacuum nipple in your exhaust after the turbo with a check valve and get safe vacuum there for this, but then you are back to having a smoke screen accelerating out of corners.
Old 04-18-08, 04:15 PM
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Originally Posted by SpeedOfLife
No.
please enlighten me then, my 10th ae started smoking, the turbo is on it's way out, bad in and out and side to side shaft play, swapping in my spare when the waste gate is done being ported.
Old 04-19-08, 02:31 AM
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Originally Posted by lastphaseofthis
please enlighten me then, my 10th ae started smoking, the turbo is on it's way out, bad in and out and side to side shaft play, swapping in my spare when the waste gate is done being ported.
You have a common problem, please search. Most answers are already there.
Old 04-19-08, 04:31 PM
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Lastphaseothis-

You are actually correct. The oil catch can is only needed once you start to modify the evaporative and crank case ventilation system (all one system).

The stock car pulls gas tank fumes back out of the charcoal cannister and crank case air into the intake tract with a vacuum fitting in the turbo inlet duct (so it has vacuum even under boost).

Once you remove the charcoal cannister you can plug the gas tank evaporative line (small steel at firewall by fuel lines) as there is a 3 way splitter w/ a pressure relief right off the gas tank in case the charcoal cannister plugs up. It will now vent to atmosphere once pressure builds above the relief pressure.

Then you can plug the old charcoal can outlet so the vacuum fitting only pulls crancase vacuum or you can take off this part of the system as well and run a catch can for crankcase ventillation.
Old 04-28-08, 10:04 PM
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So do you NEED vacum for the crankcase ventillation? I used to run a line from the oil filler neck to a catch can, then back into the intake after afm and before turbo. Now, I eliminated the line from the catch can to the intake, and I just have a breather/filter on the catch can. Ever since I've done this, I hear poping sounds from the engine bay once I get close to about 10psi under load. Is this normal? Or does the crankcase require vacum for proper ventillation?
Old 04-28-08, 10:21 PM
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No, it does not have to be vacuum as long as there is very little restriction from the sump to the breather tank.

From what I have experienced, the higher oil pressure you run the more critical it is to keep pressure from building in the sump so the oil can easily exit the turbo instead of going out the turbo rear seal.

FD gen guys have found one big hose out of the top of the oil filler cap is the best place so less oil sloshes out (mainly only a problem for FCs when you add coil overs/ race tires and corner).

If you just do the stock line at the oil filler neck and the one at the intermediate iron you are probably fine with just a breather.

I have no idea what the popping noise is.
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