911GT3

My local shop has a .2 non-RS GT3 in with devastating engine damage. When the company man came to look at the damage, he said Porsche would not cover it as the dual mass flywheel had been replaced with a single mass LWFW. That I understand. When we go modifying our cars I don't expect Porsche to cover any damage that occurs with non-stock parts. It is what he said next that bothered me: The non-RS GT3 engine is not designed to handle the LWFW and damage can occur. Is there anything different (assuming the clutch, pulley and all other things are appropriately changed) with the non-RS and RS engines that should really make the non-RS not be able to handle a properly-installed LWFW?

paver

Damn....sorry to hear. What actually failed?

9972RS

sorry to hear that. porsche warranty sucks.

911GT3

Don't know whole story, but something about bolts securing the flywheel. Obviously operator error during installation is a reasonable cause. I was just wondering if the company guy actually had any reasonable evidence for his statement. Should those of us with LWFW installed by reputable shops be concerned because of a real inherent issue with the non-RS engine? I can't see a reason, but wondered if I am missing something?

Viperbob1

BS. Installed 50+ and no issues ever. Sounds like typical CYA.

Serge944

Porsche factory service manual prohibits LWFW installation on 997.2 GT3. It very clearly states this.

RedRSA

Yes, there is a statement from Porsche stating that "due to an increasing number of reported faults" that the installation of the single mass RS flywheel is not approved and if done it voids the warranty. As one of the reasons they state that the engine was not designed for the single mass flywheel.

However, that does not address the OP's question: was there in fact any real difference between the GT3 and the GT3RS with regard to the design/installation of the single mass flywheel? A review of part numbers on PET reveals very little difference in part numbers, right down to the crank. GT3 Cups have used the same single LWFW for years with no adverse consequence.

This is a time critical question for me as my engine will be out next week for coolant line pinning and conversion to the 4.0 setup is on the table.

Fisher

This is a very real problem and has been discussed in other threads. Many of the inputs have created confusion, maybe because of incomplete failure reports. Whatever. JamieGT3 of RK Autowerks has developed a harmonic dampener that looks like a technically feasible solution. See the following discussion:

https://rennlist.com/forums/997-gt2-...cking-out.html

There are many other discussions, such as:

https://rennlist.com/forums/997-gt2-...-on-gt3-s.html

The only information I have found from Porsche is:

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

P.J.S.

Hogwash

Fisher

Bat Guano

Jamie_GT3

Our analysis shows that the GT3 and GT3RS differ in very few parts and honestly none that would say a GT3 would have damage that an RS would be immune to. Seems it's mainly the flywheel that's different... and the tuning.

If you look at the cam bolt issues on the .2, it's mainly all RS's that have the issue, very few GT3's with DMFW, if any that I've heard of...

We're trying to get the new damper out to help the .2 guys as well, it's in engineering as ATI had to redesign the carrier to be smaller than what they have done in the past.

To the OP, very sorry to hear the trouble and I agree BS on the GT3 being more susceptible than an RS...

sechsgang

Wow that's a load of ****...really a shame Porsche won't stand behind some of this stuff..its not like you are putting turbos on your gt3 and expecting them to cover a blown engine...

andrew2008

Here's some information about GT3 engine harmonics:

http://performancedevelopments.com/technical-bulletin/

I have no affiliation, just found this searching the web.

aussie jimmy

pdk will solve all of porsche's liability issues once and for all.

Metal Guru

I call BS on that.
Flywheels store energy to smooth out the power pulses that the engine generates. That's all they do.
A dual mass flywheel's (DMF) purpose is purely for NVH. It dampens secondary vibrations from the engine that manifests itself as drivetrain rattle at lower engine speeds. Switching from a DMF to a single mass flywheel will not cause the destruction of an engine on it's own.
This sounds to me like the factory going by the book on warranty claim denial once again simply because they can.
You can bet that every RSR the factory built has a lightweight single mass flywheel in it.