Re: integrated dry sump lubrification system
The best way to describe this is that it is internal to the engine and not external as a conventional dry sump is. If you have any history with Porsche 911s, then you may recall their separate oil reservoir that used to hang aft of the RR wheel. The oil filter was mounted near the top of it, and it took two drain bolts to drain the oil on those cars. The capacity was quite high,--14-15 quarts. Over time Porsche integrated the dry sumps more into the design of the engines, with the 964, 993 and some 996 engines getting a conformal sump/reservoir on the back side of the engien (as viewed from the rear). The 996 engines found in the 996TT and then the 993 engines and now the 997TT engines all have this design. The later Boxters, Caymans, and 996 and 997s have what Porsche has coined as an "integrated" dry sump. There are actually some pros and cons to them. First, on the pro side,--less oil needs to be carried in the engine. There are less opportunities for oil leaks. Cons are easily seen as,--less insurance that high G turns don't result in an engine starvation problem (for oil). In fact, on the regular 997 and 997S engines there is a warning in the manual about using high performance tires (i.e., slicks) that could generate so much lateral G force that you COULD starve the engine of necessary lubricating oils.
That's Porsche's way of saying these engines are not the competition engines they once were. I suspect Porsche did a lot of studying of this issue and found that the vast majority of "911" buyers today are not out there flogging their cars on the weekends, like used to be more the norm. As a result, they saw this as a way to eliminate the oil leaks and excessive oil capacity requirements. Once a car gets fancy with tons of comfort items you start to see less need for a dry sump. It also takes a special driver to put a current 911 into an oil starvation situation. Few 911 owners of today would qualify. So,--overkill.
The whole original idea behind a dry sump in the old days was to reduce the need for an oil pan at the bottom of the engine. Oil would be quickly scavenged from the bottom of the engine, routed to the oil reservoir or dry sump and ultimately sent through 1 to 2 oil coolers and then made available again to the engine. Porsche is still keeping the overall height of a 911 engine under control without the dry sump so the center of gravity of the engine is more than adequate for handling.
dan