Anyone removed AOS & Used hoses/breather tank - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Brad Roberts · 03-09-2012, 03:41 PM

Your GT3, pulls oil from the tank so fast, it creates a vacuum on the block and keeps the engine from leaking everywhere. Porsche Motorsports made 8-10more hp by changing the rear main seal on your GT3 engine.. you know why? That seal let the engine breath. The vacuum from the oil tank was so great, that it actually caused the rear main seal to collapse!!

We have no mechanical vacuum on the Boxster engines..

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Brad Roberts · 03-09-2012, 03:44 PM

Now, that being said.. drag racers for years have used a belt driven vacuum pump to pull upwards of 20inches of vac on the engine at high rpm (non dry sump engines)

GT3 = dry sump
9X6 = wet sump
9X7 = wet sump

Want to run a breather can? Go to a belt driven vac pump and adjust the suction side of the pump so it does not pull too much vac on the engine causing seals to collapse.

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Jittsl · 03-09-2012, 04:04 PM

Quote:

Originally Posted by Brad Roberts

Now, that being said.. drag racers for years have used a belt driven vacuum pump to pull upwards of 20inches of vac on the engine at high rpm (non dry sump engines)

GT3 = dry sump
9X6 = wet sump
9X7 = wet sump

Want to run a breather can? Go to a belt driven vac pump and adjust the suction side of the pump so it does not pull too much vac on the engine causing seals to collapse.

B

Hmmm. That may be a little more complicated than I had in mind.

Thanks for the explanation regarding vacuum. Was not aware of this. Isn't that the reverse of the old fashion PCV (positive crankcase ventilation) that so many of my early cars featured?

Brad Roberts · 03-09-2012, 04:18 PM

Bingo @PCV

Porsche has known for a long long time that pulling a vacuum on the engine was a good thing. Most european car companies do this, it wasn't until the late 90's the "merican" car companies figured it out.

PCV's pull vacuum on the engine, but it was not what we call "plenum or port vacuum" it was a simple line from the PCV to the air cleaner.

New LS GM engines have a version of our AOS on them.

12k RPM VW drag engines will make 3-4hp *more* with a belt driven pump

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