Hi all,
I'm planning to change the clutch and IMS soon, so it's good time to upgrade the flywheel.
I'm thinking about SharkWerks Light Weight Flywheel Kit. But it is single mass, my local Porsche mechanic shop told me single-mass makes more noise and vibration compares to OEM dual-mass.
So if you currently have it in your 996, how do you like it?
If you don't like it, any other suggestions?
Thank you
BTW, mine is 03 996 4S.

 

Got the same story from my dealer shop. I trust them. Jb

 

So you stick with the OEM?

 

Yes it makes a slight noise unless you press the clutch pedal...Not something intense but its continious. Plus you have to convience thw next buyer that this sound comes from a light flywheel, not a mechanical problem

 

I put a SPEC 2+ kit in my car....with LWFW.

LOVE IT!

Did not feel that much more vibration. If you let the car idle with in neutral, you'll be able to hear a little rattle coming from under the car. That's about it.

I'm also running Wevo SS motor mounts. Now THAT introduced much more cabin vibration.

 

And then there is this:

http://www.flat6innovations.com/broken-crank

Not that this is common, but Flat6 says that the only broken cranks they have ever seen where on engines with LWFW's.

 

Yep, saw that...and if you remember, I was on the fence for over 6 months about the install.

However

my dealer is the one who installed it. They're head tech is the one who told it was safe to install. He said he's installed "lots" of LWFW, some for motorsports, some for street use only...and he's never had any come back. He also stated he's never seen a broken crank on any 996. Ever.

 

+1 to the above... maybe F6I is crying wolf a little, but also...

The DMF is important on this engine, if you move to a LWFW I would personally only do so after having the engine balanced along with new thrust shims and adding a harmonic pulley (requires complete engine tear down).

By removing the dampening of the dual mass flywheel, you are placing the duty on the spring loaded clutch disc and likely more load on the thrust shims. Not saying it can't be done, but after reading several recommendations from both flat 6 innovations and ln engineering to only go with the DMF, it's not a bolt on you want to do without making some other considerations first.

At the very least with this swap if you don't have the engine balanced, I would have the new LWFW balanced and install a harmonic crank pulley to hopefully reduce your chances of that doomsday scenario.

 

As a side note I recently had my DMF balanced and it was off by 20 grams... which is a pretty significant once you start increasing RPMs.... so balancing is even something to consider with the DMF.

 

I have an AASCO and it makes noise, I wouldn't do it again if I had a chance to start over.

 

I'm not saying Jake is crying wolf...just that the "issue" might not be as cut and dry as he feels it is.

I mean, people call him when their crap explodes....not when everything is working fine. So his view might be a bit skewed.

I sat on the fence for a long time...with my kit in a box...and asked everyone I ran into that might have any relative experience. I met many weekend racers who ran LWFW and never had any issues. In fact, the only negative feedback I got was from Jake. However, since I respect his knowledge and experience, it weighed heavily in my decision. (hence the 6 month wait)

The fact that your DMF was unbalanced just proved the point however....perhaps having your engine balanced with the LWFW is overkill. I mean, you don't hear about broken cranks from unbalanced DMFs, do you?! Not warned against it like the LWFW.

Maybe the case against LWFW is more of a "guilty by association" situation...

Anyway, I've been super pleased with mine. Spent a couple days at the track in November and been driven daily. Not a single issue to report.

 

That's lots of great info, thanks all.
For the DMF, OEM is the only one to go with? Or balancing the DMF would help without changing anything?

 

I'm not 100% sure but I think the theory is the DMF (even unbalanced) is going to soak up more than a LWFW and it's accompanying clutch disc spring.

Certainly the more balanced the engine is the better it will perform, and the flywheel is just one portion of an engine balance... after having my entire engine balanced at this point going forward any flywheel I install I will have it balanced before it goes into service.

I read about an aftermarket DMF but can't place my finger on it at the moment.

In the end, I think Jake spells it out pretty clearly on the link Dharn posted above:

"1- The engine was "upgraded" to a lightened flywheel. This new flywheel was installed onto the existing stock engine without being balanced to that assembly. This created an imbalance in the rotating mass AND it did away with the factory dual mass flywheel.

2- The dual mass flywheel was removed to alow the single mass lightened unit to be installed. This eliminated ALL MEANS OF HARMONIC DAMPENING!! The crankshaft was forced to absorb ALL harmonics from the engine and transaxle when the dual mass unit was removed..

So- adding the light weight flywheel was a double negative, not only did it create imbalance, it also eliminated the harmonic dampening of the dual mass arrangement."

Regarding point 1 to my point earlier, I'm guessing that even if a DMF is unbalanced, because of it's ability to soak up imbalance with it's dampening capability, is going to be a better situation than a LWFW without the dampening capability.

Regarding point 2 I think it's pretty self explanatory. I'm not sure how much help the sprung clutch is going to do for harmonic dampening... at this point you're looking at a fixed pulley, bearings, thrust shims, crankshaft and a flywheel connected directly to the transmission through a sprung clutch disc.

 

Very true words above, certainly he sees the bad side and does broadcast a little doom and gloom. However, he probably has accumulated more knowledge about how to prevent those things than any shop by several factors.... considering he not only sees the failures but analyzes what causes them, why they happened... etc.

How many race cars don't have their engines balanced but run a fixed pulley and single mass flywheel?

How many production cars are on the road without a harmonic damper (pulley or flywheel?)?

Anyhow, as pointed out earlier, it's not like a recipe for disaster. a.) you install LWFW, and b.) your crank explodes.... but all I'm saying is if you're going to go down that road maybe protect your investment.

If you don't go through the tremendous expense of having the engine torn down, rebuilt, and balanced, at the very least perhaps install a harmonic crank pulley and have the LWFW and pressure plate balanced.

 

I have had the LWFW on my car (Aasco and SPEC stage 2+) for about two years. I absolutely love it. I did a great deal of research prior to installing it on my car. I also read the post by Jake on the broken crank...did you see how many track miles that engine had on it? I would be thrilled if my engine held up that well.
The deciding factor for me was talking to Randy Aasco. He told me about all of the race cars that are running their flywheels. I trusted his expert opinion and have had no regrets. If you are looking at a product that is sold by Sharkwerks, talk to Alex if you have any worries. He ran a LWFW on Project White Shark. I would trust his opinion.