I was just perusing the porsche site and in the engine feature, it says that the cayman has a dry sump. I was under the impression that only the gt / turbo models had this feature. I checked the regular 911s to see if they had claimed all of the motors to be dry sump but didn't find that to be the case.

(click dry sump on this page)
http://www.porsche.com/usa/models/ca...detail/engine/

If I gather correctly, the dry sump on the gt3 motor includes an external resevoir, whereas for the cayman, the resevoir is internal to the motor.

Those who are technically inclined, can someone clarify? Is the cayman motor dry sump or not? I did not there are varying degrees in this case.

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Cayman S Black.
s550
e93 m3 (in production)

The Cayman S has an integrated dry sump system. Which is a little different than many other dry sumps on race cars, which usually have a completely separate oil reservoir. This link will give a basic understanding of "wet sump" and "dry sump".

http://www.drysump.com/drysump.htm

This is what is in the Cayman S "Technik Introduction" book. " The Cayman S engine features integrated dry sump lubrication. This ensures a reliable supply of oil at all times. Two oil return pumps draw the oil out of the cylinder heads. It is defoamed via a new return system of narrow ducts and finally collected in the integrated dry sump. The weight opimized oil pressure pump collects the oil from the integrated dry sump and supplies it to the lubrication points in the engine. This principle ensures optimum oil supply even when extreme requirements apply..." A lot going on huh?

Speed Racer S,

I would also like some clarification on this topic.

A true dry sump system stores the oil in an auxiliary oil tank and feeds it by pressure to the points in the engine where it is needed. Then a scavenge pump returns the oil back to the tank.

In a conventional wet sump set up, the oil is stored in the oil pan where the crank shaft is partially submerged along with the oil pump. So, the lower part of the engine gets part of it's lubrication by the simple fact that it's partially submerged and because movement is splashing oil around the lower half. Rod and Crank bearings are still supplied with pressurized oil from the oil pump, as is the top end (cam shafts). Oil from the top end makes it back down to the oil pan via gravity.

My understanding of the benefits of dry sump are:

1. More consistent oil delivery during periods of extreme lateral forces (sharp turns) when oil in a wet sump would be forced up and to one side.
2. Less oil contamination from crankcase contaminants
3. Ability to store much more oil, extending change intervals and reducing oil temperatures.
4. Better oil cooling as the tank becomes an oil cooler as well.

Now the Cayman has an 'Integrated Dry Sump'. As I understand it, the oil is stored in the lower end of the motor, but not submerging the crank. This negates benefits 2 and 4 above. But the Cayman still force feeds oil to all points using 1 oil pump, and then returns the oil back to it's sump with two scavenge pumps, one in each head.

Personally, I don't really see why they are even suggesting it's a dry sump at all. But maybe I'm missing something. Can anyone elaborate?

Thanks,

GB

How does this relate to oil "belching" out the exhaust resulting from hard cornering in an S that doesn't seem to affect a non-S?

I mean hey, a supermodel girlfriend is great. But if she is constantly wetting herself...

After reading the cool article shared by Cayman W, we can add a few more benefits to the dry sump:

1. Less viscous drag
2. Smaller oil pan allowing lower placement of the engine, reducing the center of gravity.

If the Integrated Dry Sump works like I think, it will share benefit 1, but not benefit 2.

No one I know considers the Cayman S to be equipped with a true dry-sump engine, which would obviously be preferred for track use. Otherwise, I wouldn't worry about it. I am doing up my Cayman RS conversion for the track, so have fitted an oil-sump extension with extra windage.

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LEE in D.C.
'06 RS project
http://www.Momentum-Motorports.com

Continuing with the Porsche supplied verbage "...such as during high lateral and logitudinal acceleration. The oil supply system has been adapted to the high levels of stress imposed on the crankshaft drive and the resultant requirements imposed on the switching quality of the valve drive's adjusting elements. The delivery capacity of the oil pressure in the crankcase has also been optimized by reducing the axial play tolerances of the impellers". So maybe they needed to hire some our members to do those stress tests???

All of us old guys know that a wet sump oil system utilizes the "dip-n-splash" method for rod and main bearings, along with whatever oil gets pumped through oil galleys.

Dry sumps provide oil pressure solely by pumping. The benefits of having an integrated dry sump are:

1. less oil needed (no extra hoses to fill)
2. engine oil temperature warms up faster - so you don't have to wait as long to "drive" the car.

Since the addition of water-cooled heads, the external tank isn't of as much value as it once was. In the Cayman, there isn't really any convenient location to hold one. The solution then is an integrated dry sump.

I think that its a great idea. As long as you don't perform aileron rolls, loops, and sustained inverted flight, your engine should be adequately lubricated.

Porsche does warn about using tires with more adhesion, as it could lead to oil starvation on turning ...

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LL

Two points: 1) The crank is never submerged in oil in any engine. This is why over-filling with oil is so bad. The oil would become aerated (foamy) and not pump or circulate properly. 2) The fact that an engine has scavenge pumps to recover oil and return it to a sump, whether that sump is integral or separate, is what defines a dry sump system.

I am well aware of the advantages of a dry sump oil system or a traditional dry sump as most people call it with an external resevoir. However, I have never seen a recent Porsche motor with an integrated system fail because it wasn't a "true dry sump". The question comes down to can the system provide the oil that needs to be provided across all load conditions. If it can, then I wouldn't worry about it. If the integrated system fails then I would worry about getting something else, but as I mentioned, I haven't seen the integrated system fail.

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