How Light is Your Flywheel+Clutch? - Page 2 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

PorscheFan5 · 06-11-2015, 10:28 AM

JFP and others,

In my case where I am doing an Electric conversion of my 2004 Boxster, I wont have the engine but the DC motor. In this case should I keep the stock Flywheel or go for a LW one? What do you guys think? Somewhere I read that people changed it to LW one in an electric conversion but cannot find it now. Note that I will be mostly driving in 2nd or 3rd gear and the RPM will be anyway high.

BTW, if I am driving at highway speeds in 3rd gear, how high will the RPM be? I am thinking of using the stock RPM sensor and stock RPM meter in the dash. Just wondering if I will go out of the meter range...

maytag · 08-09-2018, 11:43 AM

revival of an old thread.
Now, three years removed from these posts, do any of you who are still here have any further recommendations regarding the Lightweight Flywheel & Sprung Clutch?
Stone?
Any others here with First-Hand knowledge who can share your experiences?

I understand the issue of balancing. I've built some very high-revving engines & I know the sort of harmonics that can occur.
What I DON't have, is experience with these cases, and what sort of abuse they'll tolerate.

I see some reports of crankshaft failure, but none are attributable to someone's first-hand experience. All are "I've heard of ....". Whereas I see several posters saying they have run the LWFW for upwards of 45k miles, with no issues.

Just looking for some experience to chime-in, before I make any sorts of decisions here.

particlewave · 08-09-2018, 01:47 PM

If you look hard enough, Jake Raby has posted first hand results of busted cranks from LWFWs.

thstone · 08-09-2018, 02:09 PM

Quote:

Originally Posted by thstone

I am up to about 62,000 miles and 94 track days and I am on the 2nd clutch (same LWFW) without a problem.

And as always, your mileage may vary.

Maybe I am lucky with clutches and unlucky with valve lifters.

** Update **

Total of 5 years, 140 track days incl 60 races, and four engines.

Still zero problems due to LWFW.

YMMV.

maytag · 08-09-2018, 02:25 PM

Quote:

Originally Posted by thstone

** Update **

Total of 5 years, 140 track days incl 60 races, and four engines.

Still zero problems due to LWFW.

YMMV.

this is goood.... :-)

So, the benefit of the LWFW is clear to you, then?

My car is still primarily a street car; is the added noise from the trans noticeable?
And driveability? I've driven lots of lightened flywheels before, (none in a Porsche) so I understand the need to rev more from a start, etc. But any other driveability issues?

maytag · 08-09-2018, 02:32 PM

Quote:

Originally Posted by particlewave

If you look hard enough, Jake Raby has posted first hand results of busted cranks from LWFWs.

still looking... can't find it.
I see where it looks like he MAY have posted a photo of it once, but no photo there any longer.
I'll keep looking. BUT I'll be honest; after reading a ton of his posts on this topic and a couple others, the guy clearly has his own agenda in what he writes, so it's a little hard to take what he's writing as unbiased, first-hand-experience. He certainly has more knowledge and experience than I do, though.

particlewave · 08-09-2018, 02:48 PM

Quote:

Originally Posted by maytag

still looking... can't find it.
I see where it looks like he MAY have posted a photo of it once, but no photo there any longer.
I'll keep looking. BUT I'll be honest; after reading a ton of his posts on this topic and a couple others, the guy clearly has his own agenda in what he writes, so it's a little hard to take what he's writing as unbiased, first-hand-experience. He certainly has more knowledge and experience than I do, though.

You won't get any argument from me on that!

particlewave · 08-09-2018, 02:53 PM

It seems he's removed the post from his site, but here are the pictures that google has saved:

j.fro · 08-09-2018, 04:58 PM

I installed the LWFW at 142000. At 189000 no problem with that ( do have a cracked head). 9 years of competitive autocrossing and all of the beating that goes with it.

thstone · 08-09-2018, 05:41 PM

Quote:

Originally Posted by maytag

this is goood.... :-)

So, the benefit of the LWFW is clear to you, then?

My car is still primarily a street car; is the added noise from the trans noticeable?
And driveability? I've driven lots of lightened flywheels before, (none in a Porsche) so I understand the need to rev more from a start, etc. But any other driveability issues?

Yes, its all good! Five years of racing Boxster's has been hugely rewarding! Engines (for me) are wear items just like tires and brakes. Some engines have lasted longer than others, but none of my engines failed due to anything related to the LWFW.

Some noise from the trans might be noticeable with the top down and the clutch out. Push in the clutch, no more noise. Top up, not noticeable. Otherwise, no drivability issues, just a little quicker to rev.

thstone · 08-09-2018, 05:44 PM

Quote:

Originally Posted by particlewave

It seems he's removed the post from his site, but here are the pictures that google has saved:

Do you know if those photos are from a Boxster? My memory wants to say that is a 996 engine but ... I'm lucky to remember my home address these days.

particlewave · 08-09-2018, 06:12 PM

I don't recall, just that it was an M96 with a lightweight flywheel.

BYprodriver · 08-10-2018, 04:12 PM

Quote:

Originally Posted by Krieger

So how about lightening the stock dual mass flywheel a couple pounds?

I have my dual mass flywheels balanced before install, but there's not a lot of room for lightening holes & still maintain dynamic balance.

mikefocke · 08-10-2018, 04:45 PM

Pray tell what benefit would Jake have re the dual mass versus lightweight flywheel choice. He makes neither so no financial incentive. And since he has been inside more failed engines than most posters here, he just might have some insight. That PCNA advises against it in a TSB also adds to the weight of the dual recommendation. Maybe if you have rebuilt your engine and balanced it to a micro ounce or if you just happened to get one balanced that way from the factory, you may be in the group that has a positive experience with the light weight flywheel. Or not...

Your car, your money, your choice.

WillH · 08-10-2018, 04:54 PM

Isn’t there a harmonic balancer pulley available for the M96?

JFP in PA · 08-10-2018, 06:58 PM

Quote:

Originally Posted by WillH

Isn’t there a harmonic balancer pulley available for the M96?

Yes, but it is not equivalent to the action of the dual mass flywheel.

Lew · 08-12-2018, 09:03 AM

Porsche wanted the lightest crank they could have and those cranks cannot stand the huge torques both in Revs and downshifting loads. Many light weight flywheels installed have caused the cranks to fail.

maytag · 08-12-2018, 10:18 AM

Quote:

Originally Posted by Lew

Many light weight flywheels installed have caused the cranks to fail.

Can you cite more than one?
In the WHOLE of the internet, I can find only one.
Please, show me "many".

Sent from my SM-G930T using Tapatalk

JFP in PA · 08-12-2018, 11:17 AM

Quote:

Originally Posted by maytag

Can you cite more than one?
In the WHOLE of the internet, I can find only one.
Please, show me "many".

Sent from my SM-G930T using Tapatalk

We have seen a couple, but also do not post everything we see on the web.....

Lew · 08-12-2018, 11:22 AM

Which one are you talking about Maytag? I remember reading a couple of articles about the reason cranks broke, and others that spoke of hearing about broken cranks that were light flywheel related were in a public conversation. I somewhat remember the article I read, and if I can find it, I will post it up for you to read. If it's a different article that you mention, that's two of the many.