more aos thinking ...
 

so, folks have talked about dumping the aos into a catch can before - done often by racers (not street legal) avoids feeding oil into your engine upon failure, more notice of aos failure as you'll see oil build-up in the catch can. you you have to occasionally drain the can when it gets filled. here's a good option:

Stage 1 Single OCC

two issues with this approach:

1) crankcase vented to atmosphere, so not environmentally friendly.
2) no longer applying vacuum to the crank case which is a bad thing as engine is designed to have this vacuum to ensure ring seating.

so, has anyone tried combining the catch can with one of these:

TRM Tuning - Crankcase Evac Kit

basically it gets vacuum from the exhaust instead of the intake.

I think these can only be run with straight pipes, otherwise you'll have positive pressure.

I have used these, but only on a race car. Exact placement of these is critical, and not always possible on a street car, plus they only generate vacuum at high exhaust flow rates making it useless on the street.

Ifyou want to go to a catch can, you will need to add a belt driven vacuum pump so that you get better vacuum at low to mid RPM's; several companies such as Moroso make them.

There are plenty of other AOS units on the market to choose from. All maintanence free.

Moroso Air/Oil Separator Tanks - SummitRacing.com

Except that none of them will create vacuum in the sump...............

instead of belt-driven, how about electric? i've read that some folks are repurposing sai pumps to create vacuum (bmw/bosch units). you'd need something robust enough to handle all the oil that it might have to process.

How it is driven is irrelevant, provided it creates a large enough vacuum signal................

-Confused-

All AOS's pull vacuum from the same place.

We are going to begin selling more of our individual engine parts soon.. But our AOS solution is not legal for street use.. The AOS is an emissions device, altering it is not legal in most places in the USA..

No, you are confusing a mechanical air oil separator, which is simply a tank like device with screens and baffles that allows air to detrain or physically come out from the oil, and the AOS system on a Porsche that is a combination mechanical device and a vacuum source (the intake manifold vacuum) to lower the ambient pressures in the sump and allow the low-tension piston rings to seal.

Engines with inherent low manifold vacuum signals, such as a race engine, using a mechanical separator by design still need a vacuum source, usually a belt driven vacuum pump.

is not the greatest need for crankcase vacuum at higher rpm, when an exhaust vacuum system would be most effective as that is when the most air is flowing past the venturi?

Yes, but as I noted earlier, the exact placement of the venturi style vacuum generation devices is critical to their performance; the angle of the exhaust flow to the device and its placement in relation to the collector system on the car’s exhaust headers makes it a difficult installation in tight confines, even on a race car. Add to that the fact that inherent low vacuum signal at lower RPM’s from a venturi system tends to cause plug fouling due to poor ring sealing at lower RPM, and even racecars started using alternative vacuum sources like pumps to provide predictable and consistent levels of vacuum across the entire RPM range.

Perhaps the ultimate solution is dry sump system. Those positive displacement scavenge pumps can pull a lot of vacuum for crankase ventilation, and a properly configured oil tank is a great air-oil separator.

Speaking of which, a guy that I autocross with who has a 2007 Carrera S told me today that the Carrera S model in particular has a dry sump system. I thought all M96 / M97 / 9A1 engines all had the same pseudo-wet sump.

Sorry, but having run several dry sump engine setups over the years, I can assure you that you still need an auxiliary vacuum source (read a belt driven vacuum pump) to properly evacuate the engine case. The dry sump pumps, even a multiple stage units, do not create enough case vacuum to do the job.

As for your autocross guy, his 2007 Carrera S has the exact same AOS setup and wet sump that you and every other M96/97 does……………

I know I'm gonna get hammered by the naysayers, but here's my setup: inline aftermarket AOS plumbed between the crippled factory unit and the intake.
My car runs well, I'm to 155,000 miles, and crikey she delivers at the auto crosses!

Here's a photo:
http://986forum.com/forums/uploads01...1346069329.jpg

Interesting - where did you get this?

It's sold through Jegs. Moroso makes a similar unit that's about twice as large and billet aluminum (and twice as expensive).

That looks like the air/water separators used in a normal shop compressed air system.

Any updates on this?
Thanks
Van