Pressurized the CrankCase Question HELP
06-28-2005, 06:00 PM
#17
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Originally Posted by ttwirz
I have this same problem with My SC N/A. oil in the intake tube after the breather hose from the crank case. What is an "AOS"
06-28-2005, 06:02 PM
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Originally Posted by Rob
Like j-chen said, just add in a reducer to get it back to the factory size. You said previously that you have access to a machine shop, Correct? Have them make you a stepped delrin bushing that just lightly presses into your larger opening. That way you won't have to pull the turbo to replace the AOS either.
06-28-2005, 06:04 PM
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Originally Posted by hosrom_951
Daniel: I would put the catchcan back on, also since the cathcan would coolect all the oil vapours in the intake, and you also drilled the AOS anways.......... you would be gaining a few ponies (talking 1 or 2, maybe a bit more??). Also, since th eair is coming in "cleaner" with the catchcan, the AFR would be better, in a sense of control.
Once i get a wideband, i would show the difference of before and after AFR with and without the catchcan all datalogged.
PS: When would you be posting the links for the video(s)?
Once i get a wideband, i would show the difference of before and after AFR with and without the catchcan all datalogged.
PS: When would you be posting the links for the video(s)?
. BUt i still wanna get a smaller hole so as much can't come out. I am waiting for this dam google upload crap to let me post my videos. it takes them a week to approve of it before it comes live. you know anywhere else i can post vids up
06-28-2005, 06:06 PM
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Please don't roll your eye's. The tube you fill er up with is the air oil separator? I though my problem was blow by since my motor is a bit tired and the Super Charger doesn't help the mater. I wonder if the set up is a bit different because in stock for the n/a does not have to acomodate presure in the system.
06-28-2005, 06:22 PM
#21
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There's always some pressure in the crankcase due to blow-by gasses. It's a matter of how much pressure you have to deal with. On most cars, the crankcase is vented from the valve-cover through a PCV valve to the intake. Basically a 1-way valve with a built-in screen.
The way the AOS works on the Porsche is internally, there's a labyrinthine path that the crankcase air takes on the way to the top to get to the breather hose. This causes the oil vapor to cool and condense somewhat and the droplets to fall out of the air and drip back down the oil-filler. The pressurized air is then sucked back into the intake by the vacuum in front of the turbo.
Numerous studies have been done on crankcase pressures. From the various hot-rod Mustang and Vette forums out there, you can figure out that introducing a vacuum into the crankcase as opposed to leaving it slightly pressurized or at ATM is worth about 15-20hp.
There may very well be some damage to Daniel's AOS as it's got cracks and sealant all over it. Internally the baffling may have been damaged. Replacing it will certainly rule that out as a cause of oil in his intake and the resultant smokey exhaust.
I've also found other instances of these symptoms caused by worn rings with large ring-gaps and lots of blow-by. The AOS in these cases were replaced with brand-new units with no reduction in oily intakes and exhausts. There was however, a reduction by running the car with the oil-filler cap off. In these cases, the cause was found easily by a compression and leak-down test. So here's some tests that should be done to determine the true cause of the problem:
- compression and leakdown tests
- modify a oil-filler cap with a port to hook up a pressure-gauge, see what crankcase pressures really are.
Those familar with stats will understand that emperical test data may show a correlation but it does not show cause and effect relationships. Good basketball players are not tall because they play basketball. Conversely, picking tall players will not automatically give you a good team. Finding workarounds or compensating effects to remove the oily intakes and exhaust may solve the symptoms, but it may not really be solving the cause of the problem. Such as getting new harder-compound tyres to solve an outer-edge wear problem, sure the worn edge is gone, but the real problem is the alignment is off. Fix the problem, not the symptoms.
if crankcase-pressure are higher than normal, finding ways to get rid of that extra pressure is not the solution; such as venting the crnakcase to ATM or running with oil-filler cap off. The solution is to fix whatever is causing you high crankcase pressures to begin with.... most likely new rings...
BTW - contrary to popular myth, while oil-vapor may displace some incoming air-volume on the intake, leading to richer mixtures and lower power, it does not lower your octane rating.
The way the AOS works on the Porsche is internally, there's a labyrinthine path that the crankcase air takes on the way to the top to get to the breather hose. This causes the oil vapor to cool and condense somewhat and the droplets to fall out of the air and drip back down the oil-filler. The pressurized air is then sucked back into the intake by the vacuum in front of the turbo.
Numerous studies have been done on crankcase pressures. From the various hot-rod Mustang and Vette forums out there, you can figure out that introducing a vacuum into the crankcase as opposed to leaving it slightly pressurized or at ATM is worth about 15-20hp.
There may very well be some damage to Daniel's AOS as it's got cracks and sealant all over it. Internally the baffling may have been damaged. Replacing it will certainly rule that out as a cause of oil in his intake and the resultant smokey exhaust.
I've also found other instances of these symptoms caused by worn rings with large ring-gaps and lots of blow-by. The AOS in these cases were replaced with brand-new units with no reduction in oily intakes and exhausts. There was however, a reduction by running the car with the oil-filler cap off. In these cases, the cause was found easily by a compression and leak-down test. So here's some tests that should be done to determine the true cause of the problem:
- compression and leakdown tests
- modify a oil-filler cap with a port to hook up a pressure-gauge, see what crankcase pressures really are.
Those familar with stats will understand that emperical test data may show a correlation but it does not show cause and effect relationships. Good basketball players are not tall because they play basketball. Conversely, picking tall players will not automatically give you a good team. Finding workarounds or compensating effects to remove the oily intakes and exhaust may solve the symptoms, but it may not really be solving the cause of the problem. Such as getting new harder-compound tyres to solve an outer-edge wear problem, sure the worn edge is gone, but the real problem is the alignment is off. Fix the problem, not the symptoms.
if crankcase-pressure are higher than normal, finding ways to get rid of that extra pressure is not the solution; such as venting the crnakcase to ATM or running with oil-filler cap off. The solution is to fix whatever is causing you high crankcase pressures to begin with.... most likely new rings...
BTW - contrary to popular myth, while oil-vapor may displace some incoming air-volume on the intake, leading to richer mixtures and lower power, it does not lower your octane rating.
