Does 997 have dry sump?

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Does 997 have dry sump?

Postby rss996 on Tue Aug 17, 2004 9:32 am

Does the 997 have a dry sump?

Thx.
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Postby kary on Tue Aug 17, 2004 10:52 am

I am sure the 997 cup cars do though I do not know that for a fact. I hope and pray the street 997's do :roll:
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Postby Bob Gagnon on Tue Aug 17, 2004 4:11 pm

The 997 engine is derivative of the 996 engine. The standard engine is essentially identical with a slightly redesigned air filter and exhaust to increase the HP from 320 to 325 or 66.5 kW/Liter.

The 3.8 liter engine is a bored out 3.6, the bore in increased from 3.78 to 3.9 inches. The engine has had some changes made to decrease pumping losses and improve crankcase venting due to the larger bore, their is a aluminum harmonic balancer fitted to the crankshaft. The cams are different and the intake is completely different made of plastic and has better flow characteristics. The exhaust is different. The net result is slightly more efficient at 68.3 kW/liter for 355 HP.

Kary's prayers are not answered though, no dry sump :beerchug:
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It's integrated

Postby B Wulff on Tue Aug 17, 2004 5:58 pm

Both the new 3.8 litre engine and the 3.6 litre engine feature the familiar integrated dry sump lubricationsystem. Similar in concept to classic dry sump lubrication, with integrated dry sump lubrication there is no external oil tank. It combines the advantage of dry sump lubrication – a reliable oil supply even with high lateral and longitudinal acceleration.

Key word here is: integrated :P
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Postby Bob Gagnon on Tue Aug 17, 2004 8:40 pm

Looking at the normal 996 design, I don't see much difference between the Porsche "integrated dry sump" and a wet sump design.

The pressure pump in a 996 draws oil from a siphon dipping into a sump below the engine which contains the oil, just like any wet sump engine. The oil from the crankshaft, pistons and connecting rods drains into the sump by gravity just like a wet sump engine.

Where the 996 has something in common with a dry sump engine is in the way the oil returns from the cam towers to the sump. It is picked up by scavenge pumps on each side which return the oil into some swirl pots within the sump that defoam the oil. This is done by necessity on the 996 since the cams are below the level of oil in the sump, gravity drainage would not work for this area.

There is a clever baffle and windage tray design which helps scrape the oil off the crankshaft and direct it to the sump, but there is still the issue of oil collecting in the cylinders as it sloshs around under cornering and braking forces in the engine.

Because of the flat design of the Porsche 996 engine this sloshing is more problematic than a 'V' or straight engine and the reason flat Porsche engines have for the most part been true dry sump, save the pushrod 356.

Porsche has done several modifications of the baffel system to keep the oil from sloshing out of the sump.

One problem with the 996 system in track use has been collection of oil in the right side camshaft tower. This is because the design of the engine places one of the scavenge pumps in front on the left and one in the back on the right side of the engine. The oil collects in the front on the right under braking and turning with the pump at the rear. Porsche designed a kit ti install an extra oil pump in front on the right side to correct this problem. This pump comes with the so called Carrera Powerkit".

I would call the normal 996 a: "complicated wet sump" not an: "integrated dry sump"; I can see why Porshe wants to use their term for marketing reasons.

The GT series engines (GT1/2/3 and Turbo) use a true dry sump with a separate large pump in the crankcase to drain the crankcase of oil and send it to a tank outside the engine. This tank functions as a swirl pot to defoam the oil as well as a supply of oil which is relatively immune from the affects of cornering and braking. The supply of oil is not free to slosh around inside the engine. Oil in the GT engines is also pumped by scavenge pumps from the camshaft housings as in a normal 996 engine but directly back to the scavenge tank.

I personally like the true dry sump, not the integrated dry sump.
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Postby sean996 on Wed Aug 18, 2004 1:18 pm

It is unethical, misleading, and false advertising for Porsche to refer to this kind of lubrication system as an "integrated dry sump".

What makes a dry sump is a seperate scavenge pump for the sump/crankcase!!!

I have to run my wet sump F car (which BTW, is an "integrated dry sump" by P's standard because it's got a bunch of baffles between the crankcase and oil sump) with an extra quart of oil to stop occasional oil starvation, so it was real important to me that the next sports car have a dry sump. It was dissapointing when I found it didn't, especially since I'd been real clear about that at purchase time. :cry:

I know you shouldn't believe what your told (especially by sales people), but I think you should be able to trust a window sticker. What's next, a new model featuring an "integrated turbocharger" which would actually be a regular 996 with an uprated alternator!!! Hopefully I'm not giving P any ideas here, there's probably plenty of potential buyers out there that would love to answer "yes" when asked if their car was a turbo! :D

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Postby David J Marguglio on Wed Aug 18, 2004 2:09 pm

Good points Sean. Misleading to be sure. So which P-cars do have a dry sump?
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Postby Bob Gagnon on Wed Aug 18, 2004 2:25 pm

All air cooled six cylinder cars (both street and racing variants including air/water cooled) have a true dry sump ie 901/911/906/935/910/956/962 etc.

All racing 4 cam engines from 550 Spyder to 904 have true dry sump, as well as all 356 Carreras.

All water cooled six cylinder cars that have engines based on the air-cooled 6 cylinder crankcase i.e the GT1/GT2/GT3/Turbo engines, have true dry sump.

The 907/908/917/771 etc have true dry sump.

Funny until the "integrated dry sump" we didn't need to use the term "True" dry sump.
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Postby Jad on Wed Aug 18, 2004 2:34 pm

Not to defend Porsche, as I would rather have the true dry sump on my Targa even though it is only occasionally tracked, but on the street is there any advantage to the dry sump? and doesn't it add quite a bit more weight, complexity and volume of oil? If I am correct in that, I can see why Porsche did it considering the percentage of new cars that actually see the track.
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Postby Bob Gagnon on Wed Aug 18, 2004 4:36 pm

I think the dry sump is probably NO advantage for street use, but it goes to what myself and other old farts consider as part of a "real" Porsche.

The old cars were made by gear heads* and were appreciated by gear heads.

The new cars are made by corporate bean counters and not appreciated by gear heads.

*Gear head: Crazy, obsessive individual who has taken his car apart and put it back together, used to be a common person to find, grease under finger nails, a dying species.
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Postby MikeD on Wed Aug 18, 2004 4:54 pm

Bob Gagnon wrote:The GT series engines (GT1/2/3 and Turbo) use a true dry sump with a separate large pump in the crankcase to drain the crankcase of oil and send it to a tank outside the engine. This tank functions as a swirl pot to defoam the oil as well as a supply of oil which is relatively immune from the affects of cornering and braking. The supply of oil is not free to slosh around inside the engine. Oil in the GT engines is also pumped by scavenge pumps from the camshaft housings as in a normal 996 engine but directly back to the scavenge tank.


It would appear that they have the technology to make a true dry sump an option. Just use the crankcase (and other necessary parts) off the GT production line. Not that Porsche would ever do that, but it seem possible, right?

I assume that as the 996 and 986 share a similar engine design the 986 would have the same starvation issues?

Is it possible to turn an "integrated dry sump" into a "true dry sump"? I.e. can Sean and/or I turn our cars into dry sump cars? Seems possible, although expensive.
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997 sump

Postby tb911 on Wed Aug 18, 2004 8:22 pm

From what I have read, the 997 has an "improved" integrated dry sump. I guess you can read that as an improved "wet" sump.
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Postby Bob Gagnon on Thu Aug 19, 2004 8:05 am

Mike-

I guess you could say dry sump is an option in the form of a GT3, GT2 or Turbo since they have a dry sump engine.

I guess one could technically add a dry sump pump to a normal 996, I have even seen it done on a pushrod 356. It would take a lot of "hot rodding" to do it though and the end result would not be as effective, since the entire crankcase really has to be redesigned to do it right. There would be no advantage to doing this unless for racing reasons in a class where you had to run the 996 crankcase.

Here's a little history on the latest GT/Turbo engines in the GT2 GT3 and Turbo cars.

Their engine really is a modified air cooled 911 engine that started life in 1963 in the first 911 cars. The air-cooled 911 engine is a modular design with a separate crankcase which accepts individual cylinders topped by individual cylinder heads. This modular design allows easy design changes and changes in displacement.

This very flexible 911 engine was modified into many variants for racing use, the 904/6,906,910,911RSR are a few using this engine.

In the mid 70's, water-cooled 4-valve cylinder heads were added to the 911 engine in the 935 creating a hybrid water-cooled head/air-cooled cylinder engine. Variants of this engine were used in the racing 936 and 962 as well as the 959 street engine.

Finally in the late 90's the engine was modified for the Le Mans GT1 cars when water jackets were added over the cylinders to create a fully water cooled engine. This basic engine is the same one that is in the current GT2/3/Turbo.

Through all this change the basic dry sump crankcase design that started in 1963 was retained and if you look under the first GT3 cars imported to this country you will see the same basic casting as under any air-cooled car. About half way along in production of the Mk2 GT3 the crankcase was changed to eliminate any external casting elements of the air-cooled crankcase. No internal changes of note were made.

So if you want to see Porsche history at it's best look at one of these engines. Technically, since the bolt pattern is the same, one of these engines could be bolted up to a 356 transmission!!! It is a very complex engine to manufacture with separate water jackets and cylinders. I am suprised Porsche has not re-designed it to simplify construction but save the basic design elements.

The normal 996 engine on the other hand, is a non-modular design with cylinders and crankcase cast together as one lump. The cylinders use a similar technology to that intoduced on the Chevy Vega and also the 928 and 944. As mentioned to save money the dry sump was eliminated.

This lack of history and blatant change in philosophy to make this lower cost alternative engine (and transmission, another story) in the 996 is what turns some people off. Particularly when Porsche makes the most money per unit of any manufacturer and it wouldn't have cost that much more to do it right. It makes me sick when Porsche management get up and make a speech, as I understand was done at a PCA Parade recently, to enthusiasts about how much money they are making.......keep the faith, your humble gearhead, Bob G. :beerchug:
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bean counters and grocery getters....

Postby gulf911 on Thu Aug 19, 2004 8:59 am

Unfortunately for you Jad, Bob and others points regarding whats a Porsche rings true. The 996 was designed for the masses/ grocery getter. Yes, its lighter, has new/better suspension, and is faster, for what? The street? . Why wrap it up with a shell that looks like a pill bug? Porsche's actual sports car (GT3) doesn't even use the same freakin engine, what does that tell you? If you want a sports car that also looks and feels like a sports car buy a 993. :shock:
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Postby Jad on Thu Aug 19, 2004 10:13 am

No, I still like my decision as my 996 is not a full time track car, it is a freakin street car that has more than adequate oiling :P . "wet sump" is not going to be a problem for its intended use. If I were going to race a car seriously, I would get a 944 Turbo to be cost effective :lol: , or an early 70's 911 for serious full track car or just a very fun car to drive :shock: . (yes, the truth be told, I think the old 911's are pretty cool and fun even if the coolant is missing) The 993 still remains a compromise on everything, great at nothing car (other than the looks of the tail, which is nice, but looks of a track car are very subjective and not that important to me- see turbo painted by spray paint) 8)

I briefly considered getting a GT3 (also looks like a pill bug?), but it does nothing better as a daily driver/family minivan/grocery getter which is what it will be used as. Paying $50-$100K for a factory stock car to race is not good money management. You can go way faster for way less money. The regular 996 is PLENTY fast and well built to get us around town or even a tour to Julian with a reasonably smooth ride, quiet, good stereo, comfortable seats, enough clearance to clear curbs and speedbumps and be tons of fun. You get the idea, it is a streetcar and that is how it will be used and it is VERY fun as such. 8)

Remember, the 993 is the car that Kary was complaining shouldn't have to compete with Boxster S and 996 as they are way too fast and should have their own class, so I guess they can make at least one or two laps :D . Maybe driven as slowly as the 993's, they would last as long as the 993 (ouch). :wink:

Dan,
Please explain to me why you wouldn't want to build a racecar from and early 911 instead of a 993? You have already agreed the 996 is " lighter, has new/better suspension, and is faster," kinda what I was going for along with smoother, quieter and easier to drive in traffic, etc etc....Thus, the same old point, there are better Porsches than the 993 for everything and it bothers me (can you tell :wink: ) that a small number of people try so hard to convince the world that the 993 was essentially perfect in every way. Not even jokingly with respect like the 911 vs 944 debate where I think both sides see the plus's and minus's to both cars.
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