Lightweight flywheel now installed / 997.2 C4S

[JonnieD]

Unfortunately you cannot compare across different models because the gearbox itself it fundamentally different.

There are too many factors involved and noise primarily is down to other factors such as diff backlash, end float measurements and how the gears are spread.

You can have two 997 Turbos for example, fit the exact same LWFW and have totally different noise results for the reasons above.

In the case of the 997.2 we rebuilt the gearbox so we were able to set all the right tolerances. You cannot assume that fitting the same identical LWFW on another 997.2 will give the same results in terms of noise, unless you are building the gearbox and setting up the diff etc.

Older Porsche models ( 993 and before ) again are more reliable in outcomes because of the design of the gearbox.

Ken

Useful insight, thanks Ken. And great job by you guys on mine :thumbs:

I can see why the gearbox differences between the models would explain why a lightweight flywheel would act in a certain way. But hadn't considered the same gearbox in different cars acting differently too.

Is it that the tolerances in the newer gearboxes vs older ones that are very different, or the gearbox design itself?

 

[NineExcellence]

Unfortunately you cannot compare across different models because the gearbox itself it fundamentally different.

There are too many factors involved and noise primarily is down to other factors such as diff backlash, end float measurements and how the gears are spread.

You can have two 997 Turbos for example, fit the exact same LWFW and have totally different noise results for the reasons above.

In the case of the 997.2 we rebuilt the gearbox so we were able to set all the right tolerances. You cannot assume that fitting the same identical LWFW on another 997.2 will give the same results in terms of noise, unless you are building the gearbox and setting up the diff etc.

Older Porsche models ( 993 and before ) again are more reliable in outcomes because of the design of the gearbox.

Ken

Useful insight, thanks Ken. And great job by you guys on mine :thumbs:

I can see why the gearbox differences between the models would explain why a lightweight flywheel would act in a certain way. But hadn't considered the same gearbox in different cars acting differently too.

Is it that the tolerances in the newer gearboxes vs older ones that are very different, or the gearbox design itself?

We have built many gearboxes and the tolerances when stripping are always different like for like boxes. As I mentioned this is why the same two models with similar mileage can have completely different experiences with LWFW from 996 onwards. The design of the LWFW can also impact as well.

 

[Cheib]

Interesting read OP. I am quite surprised about the fact there is not much 'chatter" but it is also interesting to read 9eEs comments so I guess there's good reason for going to people that know what they're doing when you fit one. I remember reading a review on Sharwerks website of various 997 fettling options....they said that a LWFW was not for everyone because of the noise....

In terms of characteristics it sounds really interesting in how it's changed the way the engine revs. I love my 997.2 GTS but I am lucky enough to own a GT3 now as well and the one thing I really notice in the GTS is how the engine feels almost a bit 'lazy" because of how relatively long it takes the revs to drop on the engine. I actually drive the car in Sports mode because the throttle is a bit more sensitive I found when H&T'ing that negates some of that lazy feel as the throttle is a bit sharper.

 

[JonnieD]

Interesting read OP. I am quite surprised about the fact there is not much 'chatter" but it is also interesting to read 9eEs comments so I guess there's good reason for going to people that know what they're doing when you fit one. I remember reading a review on Sharwerks website of various 997 fettling options....they said that a LWFW was not for everyone because of the noise....

In terms of characteristics it sounds really interesting in how it's changed the way the engine revs. I love my 997.2 GTS but I am lucky enough to own a GT3 now as well and the one thing I really notice in the GTS is how the engine feels almost a bit 'lazy" because of how relatively long it takes the revs to drop on the engine. I actually drive the car in Sports mode because the throttle is a bit more sensitive I found when H&T'ing that negates some of that lazy feel as the throttle is a bit sharper.

Lucky man having a GTS and a GT3 :thumbs:

As well as the gearbox tolerances per the 9e comments, I think the noise is also dependent on which engine its used on. I've certainly noticed more noise on the M96/97 normal and Mezger engines than on mine and one other MA1 engine (on a 981 GT4) I've heard.

I'd be interested to hear what the lightweight flywheel was like on a GT3 R, which is the most recent car Porsche offered it on. The newer ones including your 991.2 don't but I've read that Porsche said it doesn't need one due to the new crankshaft design and ultra low friction in that engine. That's probably what you're noticing compared to the GTS.

I don't know what the Sport is like on a 997.2 as mine doesn't have it, though I did have something similar on my E92 M3, which sharpens the throttle response. But I do notice a big difference on mine now with the new flywheel over how the throttle response was before, and doing more driving recently, I'm convinced its quicker in the low gears on acceleration. Pickup is very fast now, its really impressive.

I don't where you're based, but if you're close by you could certainly give mine a try comparing it to the GTS.