LWFW question...
10-31-2008, 12:14 PM
#31
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for those, "I'll believe it when I see it guys"...
Technical Information
Service
36/08 ENU 1360 1
GT3 Engine: Flywheel and Pulley
Vehicle Type: 911 GT3 (997)
Model Year: As of 2007
Concerns: Flywheel and pulley
Information: Replacing dual-mass flywheel with single-mass flywheel.
We have discovered that the dual-mass flywheel, which is installed as standard in the GT3 engine (vehicle type 997810/-811), is being replaced in the dealer organization with the single-mass flywheel from the GT3 RS engine (vehicle type 997850/-851).
Information
Due to an increasing number of reported faults, we expressly wish to point out that the installation of the single-mass flywheel (from the GT3 RS) in the GT3 engine is not approved by Porsche.
Since the 911 GT3 (997) engine application is designed for the dual-mass flywheel, conversion to the single-mass flywheel results in the following problems and consequences:
• The single-mass flywheel causes fluctuations and vibration in the lower rpm range, thereby reducing the smooth-running performance of the engine.
• The crankshaft is subjected to one-sided loading, causing stress peaks that can result in damage to the crankshaft.
• The one-sided loading of the crankshaft can cause the pulley to come loose, resulting in damage to the belt drive and engine.
• Any damage relating to conversion or damage that can be attributed to conversion is not covered under warranty.
Please advise your customers of this information accordingly.
©Porsche Cars North America, Inc.
October 15, 2008
Technical Information
Service
36/08 ENU 1360 1
GT3 Engine: Flywheel and Pulley
Vehicle Type: 911 GT3 (997)
Model Year: As of 2007
Concerns: Flywheel and pulley
Information: Replacing dual-mass flywheel with single-mass flywheel.
We have discovered that the dual-mass flywheel, which is installed as standard in the GT3 engine (vehicle type 997810/-811), is being replaced in the dealer organization with the single-mass flywheel from the GT3 RS engine (vehicle type 997850/-851).
Information
Due to an increasing number of reported faults, we expressly wish to point out that the installation of the single-mass flywheel (from the GT3 RS) in the GT3 engine is not approved by Porsche.
Since the 911 GT3 (997) engine application is designed for the dual-mass flywheel, conversion to the single-mass flywheel results in the following problems and consequences:
• The single-mass flywheel causes fluctuations and vibration in the lower rpm range, thereby reducing the smooth-running performance of the engine.
• The crankshaft is subjected to one-sided loading, causing stress peaks that can result in damage to the crankshaft.
• The one-sided loading of the crankshaft can cause the pulley to come loose, resulting in damage to the belt drive and engine.
• Any damage relating to conversion or damage that can be attributed to conversion is not covered under warranty.
Please advise your customers of this information accordingly.
©Porsche Cars North America, Inc.
October 15, 2008
10-31-2008, 12:26 PM
#32
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10-31-2008, 12:59 PM
#33
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I guess nobody wants to mention the White Elephant in the room "overrev" after trudging the dual mass around the motor reponse is a little up on the driver in catching the revs. If it was out of balance enough to break a crank it would also mess your hair up while you were driving it.
regards
regards
10-31-2008, 02:32 PM
#34
Rennlist Member
you have to keep in mind that the broken crank that was shown was not in a GT3 motor...there are no instances of a broken crank in a GT3 motor that I know of...also, there are many, many 996 GT3's that have the lwfw mod and have not had problems....I guess if 996's started flooding in for warranty repairs due to lwfw and front pulleys a new statement including the 996 GT3 would follow...according to my dealer they now won't install lwfw in a 996 GT3either...
10-31-2008, 05:47 PM
#35
I wonder if the crank in the 996 and Gt1 based engines are the same. Not the Case, sump etc as this is the part that failed.
Porsche has been for years producing dual mass flywheels for the boxer engine I believe to cure harmonics particular to this design. A single mass FW would eliminate any relief offed by a dual mass FW.
Also stated were 12,000 ! Miles of track use. I'm amazed that it didnt blow before. A tribute to Porsche engineering.
The el cheapo (in comparison) American V8 aftermarket produced a liquid filled harmonic balancer for race engines. I wonder if one could be adapted for a dedicated Porsche track car.
I also agree that engine and flywheel are balanced separately and should work together. In a Indy/F1 car I'm sure they are balanced as an assembly for weight and extra efficiency.
Porsche has been for years producing dual mass flywheels for the boxer engine I believe to cure harmonics particular to this design. A single mass FW would eliminate any relief offed by a dual mass FW.
Also stated were 12,000 ! Miles of track use. I'm amazed that it didnt blow before. A tribute to Porsche engineering.
The el cheapo (in comparison) American V8 aftermarket produced a liquid filled harmonic balancer for race engines. I wonder if one could be adapted for a dedicated Porsche track car.
I also agree that engine and flywheel are balanced separately and should work together. In a Indy/F1 car I'm sure they are balanced as an assembly for weight and extra efficiency.
10-31-2008, 11:35 PM
#37
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Actually I think the dual mass is essentialy designed to reduce drive train noise more than act as a harmonic balancer. If it was designed to reduce torsional vibration why would they have designed a component that has a "part life" in the inception. The dual mass center section ( the part that essentially flips flops not slips such as a Lancaster dampner) shows signs of premature wear in many cases, the elastonmer literaly pukes out. If this is tantamount to engine life why the poor design?
