2002 Boxster S smoking when turning left at the track

[paganrj]

Hi there!
I have a 2002 Boxster S that I drive regularly and also use at the track. A few months ago, while at the track, it started smoking heavily after tight left turns. It will quit doing it after a few seconds but will do it again in the same left turns. Thought it was hi oil level but it was ok initially and went lower after couple of sessions.
Changed the AOS (OEM, not the cheap one) and went back to the track a few weeks after but the situation happened again in the same conditions. Took the old AOS apart and found that the diaphragm was in good shape, no damage or cracks. That makes me believe that the issue is not related to the AOS.
I was told to check the scavenger pumps, took both out and they look fine, there was no visible wear. The car came with the X51 baffle when I bought it, don't believe it has anything to do with it.

What else can be causing this oil ingestion?

The car is driven on the road on a regular basis without smoking or any other issues. It has also been tracked for a long time with the same modification and never had that issue before.

Thanks for any suggestions you might have. Rey

[tonythetarga]

What type of oil are you using. Regular motor oil, even Mobil 1, has detergent in it. That foams up when driving in high speed track conditions. You should consider using Motul or Redline racing oil.
Also, if you are using R-compound tires, the g-loading will allow sloshing oil to get into the AOS and smoke.
Your oil level for track should be at least one bar down from full. That’s only about a cup of oil. If it is at the full mark, you’re too full for track use.

[JFP in PA]

I'd make that two bars down from the full line.

[mikefocke]

A deep sump pan? Baffles? Pickup tune extension? Stock? Stuff like https://www.pelicanparts.com/search/?q=deep+sump&redir=yes&host=search or https://www.pelicanparts.com/search/?q=sump+baffle&redir=yes&host=search

[paganrj]

Originally Posted by tonythetarga

What type of oil are you using. Regular motor oil, even Mobil 1, has detergent in it. That foams up when driving in high speed track conditions. You should consider using Motul or Redline racing oil.
Also, if you are using R-compound tires, the g-loading will allow sloshing oil to get into the AOS and smoke.
Your oil level for track should be at least one bar down from full. That’s only about a cup of oil. If it is at the full mark, you’re too full for track use.

I have always used Mobil 1 and for the first few years it never smoked under the same conditions and track. I will reduce the oil level for next event to see what happens but after burning a lot of oil in one session I went out again with level about half way and it kept smoking bad in the same turns. Thanks for your recommendations

[paganrj]

Originally Posted by mikefocke

A deep sump pan? Baffles? Pickup tune extension? Stock? Stuff like https://www.pelicanparts.com/search/?q=deep+sump&redir=yes&host=search or https://www.pelicanparts.com/search/?q=sump+baffle&redir=yes&host=search

Yes, the car came with deep sump pan and baffles when I bought it.

[paganrj]

See the attached pictures how it starts smoking after turning left then it fades away. I have been driving the car in the same track for 4 years and the previous owner for another 3 or so with the same equipment on it (street tires now, soft compound before) and this never happened before, something went bad and doesn't seem to be the AOS. Thinking about installing an additional catch can but that will be a patch not a solution to the problem.

[mikefocke]

Anti-freeze level? That looks white.

[paganrj]

Originally Posted by mikefocke

Anti-freeze level? That looks white.

The smoke is blue and water level never dropped.

[tonythetarga]

Well…it’s too much oil to drip on the exhaust, so it seems to me it has to be getting sucked into the intake under g- loading. That sounds like AOS all day long to me. Even a new one can be defective.
Perhaps there is a vent line that is blocked or kinked causing oil to get sucked into the intake.
Have you tested the AOS with a manometer?

[paganrj]

Originally Posted by tonythetarga

Well…it’s too much oil to drip on the exhaust, so it seems to me it has to be getting sucked into the intake under g- loading. That sounds like AOS all day long to me. Even a new one can be defective.
Perhaps there is a vent line that is blocked or kinked causing oil to get sucked into the intake.
Have you tested the AOS with a manometer?

I agree with you Tony, I found unusual amount of oil in the intake. The only reason I'm thinking is something other than the AOS is because the failure point of it is the diaphragm and it was good on the one removed. The diaphragm has a spring that keeps it open under low vacuum from the intake suction and closes it at WOT, overcoming the spring force. That doesn't happen when the diaphragm is compromised and oil gets into the intake.
When you mention vent lines, which ones specifically you are referring to? I will need to check them.
I have not tested the new AOS with a manometer, I will do that. I will also be installing an oil catch can between the AOS and the intake to see what happen next time I use the car on the track. Thanks.

[CarGuyNeil]

Originally Posted by paganrj

I agree with you Tony, I found unusual amount of oil in the intake. The only reason I'm thinking is something other than the AOS is because the failure point of it is the diaphragm and it was good on the one removed. The diaphragm has a spring that keeps it open under low vacuum from the intake suction and closes it at WOT, overcoming the spring force. That doesn't happen when the diaphragm is compromised and oil gets into the intake.

When you mention vent lines, which ones specifically you are referring to? I will need to check them.

I have not tested the new AOS with a manometer, I will do that. I will also be installing an oil catch can between the AOS and the intake to see what happen next time I use the car on the track. Thanks.

Do you have the Porsche Motorsports AOS?

Sent from my SM-S908U using Tapatalk

[2.7RS]

Originally Posted by CarGuyNeil

Do you have the Porsche Motorsports AOS?

Sent from my SM-S908U using Tapatalk

My thoughts too.

You are probably getting faster and faster. Time for track upgrades

[tonythetarga]

Originally Posted by paganrj

When you mention vent lines, which ones specifically you are referring to? I will need to check them.

I guess what I mean is that there is probably more vacuum than you need. The air filter clogging up is one way it may create more vacuum and the pvc valve is another. The AOS is the main crank vent.

[paganrj]

Just replaced the AOS again and will test the car at the track this weekend. Also installed an oil catch can to see if that helps.

[CarGuyNeil]

Best of luck.

Sent from my SM-S908U using Tapatalk

[paganrj]

New AOS (3rd), Redline oil, oil level two bars down, a catch can installed and oil still going into the intake. Less than before but still smoking some. Emptied the catch can after very track session and it had about 1/2 quarter of oil each time. In the picture you can see oil in the temporary clear hoses going and coming from the catch can.



Also found that the connector between the vent line and the block seems to be leaking, there was oil coming from that engine area. I don't believe it has anything to do with the main issue but I will replace it, it seems like it has a spring loaded valve on it.



Next step, looking at replacing both scavenger pumps with spares that I have.
I would not mind installing the Motorsports AOS if I was sure that the problem is the AOS, so far it does not seem like it is.

[CarGuyNeil]

Thanks for the update. Best to you to find a solution. Keep us posted.

Sent from my SM-S908U using Tapatalk

[paganrj]

I am wondering if this can be caused by engine blow-by

[mistertate]

Excessive crankcase pressure, could be. Do a leak down test