The AOS (air-oil separator) is NOT the culprit!
10-05-2010, 12:24 AM
#16
Racer
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If a TSB exists for the smoking upon startup and it involves a DME reflash -- I don't recall where I heard this maybe from my Porsche tech friends -- then there' s not much a DME reflash can do but fiddle with injector timing, injector pulse widths, VarioCam timing and lift (if car equipped with VarioCam Plus).
Just thinking out loud: Perhaps the new DME lets the engine crank a few more revs before it enables the fuel injectors and throws in some adjustments consisting of some combination of valve timing/lift tweaks only upon startup of shortly after which will help evacuate the oil in the chambers and lower the amount of smoking upon startup or possibly eliminate it entirely.
I'll see if I can learn anything more about this from my Porsche tech contacts.
Sincerely,
Macster.
Just thinking out loud: Perhaps the new DME lets the engine crank a few more revs before it enables the fuel injectors and throws in some adjustments consisting of some combination of valve timing/lift tweaks only upon startup of shortly after which will help evacuate the oil in the chambers and lower the amount of smoking upon startup or possibly eliminate it entirely.
I'll see if I can learn anything more about this from my Porsche tech contacts.
Sincerely,
Macster.
Avoiding looking for smoke would be like you stop thinking about the AOS... from time to time they both show up, even when we don't want them to, just to remember us that they exist.
10-05-2010, 04:13 PM
#17
Race Director
I most prefer this post of yours. Gladly you heard about it... friends you can trust... dealers not always.
Avoiding looking for smoke would be like you stop thinking about the AOS... from time to time they both show up, even when we don't want them to, just to remember us that they exist.
Avoiding looking for smoke would be like you stop thinking about the AOS... from time to time they both show up, even when we don't want them to, just to remember us that they exist.
I know my car, my Boxster anyhow, has an AOS. I don't lose any sleep over it. After 235K miles, I know the Boxster well enough to know it will smoke upon startup sometimes. All other things being equal, the smoking frequency appears to increase as the oil accumulates miles. Just had the oil/filter changed yesterday with a bit over 5K miles on this oil so I expect any smoking events will be a long time in reappearing.
What I do is just note that the smoking when it occurs falls into the behavior pattern that is normal for what my car has done in the past. Absent any other signs of trouble/distress I just let 'er smoke. No biggie. But as soon as the smoking changes and for the worse you can be sure I'll have the car in for its 3rd AOS R&R.
Sincerely,
Macster.
10-05-2010, 11:54 PM
#18
Racer
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I understand that the AOS is an issue with your Boxster. There is also a TSB from Porsche addressing just that: Boxster Technical Information 'Blue Smoke Emitted by Engine, Installation of Modified Oil Mist Separator' 02.03.2004 bx1014e.doc Vehicle Type: Boxster/Boxster S; Model Year: As of '03 (3).
With my experimenting i've just showed you that on gen2 base Caymans the problem isn't the AOS... and the Porsche TSB seems to confirm it as they talk about of a DME reflash.
10-06-2010, 06:01 PM
#20
Race Director
Then, the only difference between your Porsche tech and mine is that mine didn't just tell me... he actually showed me the TSB addressing blue smoke upon cold start-up on '09 gen2 base Caymans/Boxsters.
I understand that the AOS is an issue with your Boxster. There is also a TSB from Porsche addressing just that: Boxster Technical Information 'Blue Smoke Emitted by Engine, Installation of Modified Oil Mist Separator' 02.03.2004 bx1014e.doc Vehicle Type: Boxster/Boxster S; Model Year: As of '03 (3).
With my experimenting i've just showed you that on gen2 base Caymans the problem isn't the AOS... and the Porsche TSB seems to confirm it as they talk about of a DME reflash.
I understand that the AOS is an issue with your Boxster. There is also a TSB from Porsche addressing just that: Boxster Technical Information 'Blue Smoke Emitted by Engine, Installation of Modified Oil Mist Separator' 02.03.2004 bx1014e.doc Vehicle Type: Boxster/Boxster S; Model Year: As of '03 (3).
With my experimenting i've just showed you that on gen2 base Caymans the problem isn't the AOS... and the Porsche TSB seems to confirm it as they talk about of a DME reflash.
I'll be sure to bring this TSB to the attention of the Porsche techs I interact with and see if in return one will give me a copy of the TSB for my records.
Sincerely,
Macster.
10-07-2010, 08:41 AM
#21
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10-09-2010, 03:51 PM
#22
Race Director
Also be sure to bring the Boxster TSB (02.03.2004 bx1014e.doc) to their attention because if the smoking in your Boxster changes and for the worse you do NOT need to have the car in for its 3rd AOS R&R, BUT for a Modified Oil Mist Separator (as per the TSB). It will be most likely the 1st and the last you need to install.
I did a search on that document and except for the hit here it shows up nowhere else. How did you learn about the document? Can you supply a copy to me?
Sincerely,
Macster.
08-29-2016, 06:50 PM
#24
Rennlist Member
I went back to the Sixties and converted the GEN2 Cayman PCV system into a 'road draft tube'. 
I disconnected the crankcase breather line from the intake manifold (PN: 9A1 107 515 01) and also the vent hose from the AOS to the intake manifold (PN: 9A1 107 520 01). Thus, i do NOT have any connection what so ever from the AOS to the intake manifold, meaning that NO oil can enter the intake tract and seep into the cylinders via the AOS. The respective intake manifold inlets are both sealed.
In order to still vent the crankcase i connected a 'road draft tube' to the AOS outlet (intake manifold side) that goes under the car, and have sealed the crankcase breather line (intake manifold side) but allowing some 'fresh air' entering a little hole (the size of a needle) to still vent the crankcase through the heads. This way the AOS works like a 'catch can' which can return the oil droplets to the sump while it routes the vapors directly to the atmosphere via the 'road draft tube'... Do i smell oil outside the car? Yes i do!
The question is... does the exhaust still smoke upon cold startup?
YES!
Car works perfectly (although i do NOT recommend this mod) but it STILL smokes upon cold startup - same HUGE cloud. So, the conclusion is obvious: on the GEN2 base Cayman the AOS is NOT responsible for the smoke.
From where do you think the oil is coming up? Any ideas?
I disconnected the crankcase breather line from the intake manifold (PN: 9A1 107 515 01) and also the vent hose from the AOS to the intake manifold (PN: 9A1 107 520 01). Thus, i do NOT have any connection what so ever from the AOS to the intake manifold, meaning that NO oil can enter the intake tract and seep into the cylinders via the AOS. The respective intake manifold inlets are both sealed.
In order to still vent the crankcase i connected a 'road draft tube' to the AOS outlet (intake manifold side) that goes under the car, and have sealed the crankcase breather line (intake manifold side) but allowing some 'fresh air' entering a little hole (the size of a needle) to still vent the crankcase through the heads. This way the AOS works like a 'catch can' which can return the oil droplets to the sump while it routes the vapors directly to the atmosphere via the 'road draft tube'... Do i smell oil outside the car? Yes i do!
The question is... does the exhaust still smoke upon cold startup?
YES!
Car works perfectly (although i do NOT recommend this mod) but it STILL smokes upon cold startup - same HUGE cloud. So, the conclusion is obvious: on the GEN2 base Cayman the AOS is NOT responsible for the smoke.From where do you think the oil is coming up? Any ideas?
A small hole someware would be required to let air into the engine but small enough to maintain vacuum.
This system would eliminate oil fumes from going into the intake and lowering engine performance.
A small electric vacuum pump is available from Summit for a couple hundred bucks and the required plumbing would be very easy.
I am planning to look into doing this for my Cayman. If it works, it will be a much better solution than the AO valves offered by Porsche.
Comments?
08-29-2016, 06:57 PM
#25
