LWFW would love some pointers!

[Robert986]

I´m seriously considering putting on a lightweight flywheel.. As always I google like crazy first when trying things I haven´t done before ;-)

I know that it will be harder to use in daily traffic but this car is a bit track oriented.. Also know about the risk due to lack of harmonic damping. I plan to use a pulley with harmonic damper to mitigate somewhat. (Eg. RSS 608 - Harmonically Damped - Underdrive Performance Pulley Kit)

Sorry for my newbie questions..

1) How high do I really need to lift the car to get to remove the gearbox properly? I have a feeling I need to invest in a set of new, higher jacks..

2) I got an offer on a FW made in iron (4.5kg) whats the deal with a iron FW? Is it better/worse/other benefits related to the alu FW? is 4.5 unreasoneable light, am I better of with a little heavier?

3) The clutch.. Do I need a sprung clutch or can I use the oem? I guess my question is "should I" I understand that there will be some ratteling with the unsprung, but will it hurt the drivetrain?

[Starter986]

I will say 20 inches. 23 inches comfortable.

[Robert986]

Originally Posted by Starter986

I will say 20 inches. 23 inches comfortable.

Thanks man!

[Gilles]

Hello Robert,

There has been several documented crankshaft failures due to removing the DMFW as you will no longer have the harmonic balancer effect that is build into the DMFW..

However you may want to explore installing a front pulley that has a balancer build into it, I believe that some of the GT3's came this way from the factory, this should help you to counteract the bad harmonic vibrations that cannot be cancelled with a low weight flywheel.

Please note that by any means I am no expert on this subject.. but have been reading about for more than two decades ever since I installed a LWFW on my 1.5 Fiat X1/9 and then into a 3.0 Alfa V6, but somehow I chicken out on the 987CS ...LOL

One thing for sure is that you Will Love the way how quick the engine will rev up (and down..) after installing a LWFW..

Good luck with your project
.

[Quadcammer]

I would skip the lwfw honestly. Even with the harmonic dampner, you still have the shock from the transmission if you aren't exact on your rev matching.

And yes you would want a sprung clutch disk.


Tranny out...20 inches is fine, but i agree around 2 feet makes working conditions more favorable.

I've got the job down to about an hour to remove, slightly longer to reinstall.

[rfuerst911sc]

I love my LWFW but in my situation everything was balanced as the engine was being built . I have no funny vibrations or issues other than at idle the transmission gear stack is noisy . It's just part of the process with this type of flywheel . If you or whoever is going to do the swap does NOT have the ability to balance I would hesitate going down this route .

[Hasbro]

Not sure what lump the op has but I believe there is a thread on this forum where Jack Raby said the 2.5 is pretty much ok at handling the resulting harmonics from a lwfw, whereas the others required more balancing attention. Anyone have opinions about that?

[Hasbro]

This might be worth perusing.
Lightweight flywheel a bad idea?

[Robert986]

Oh sorry for my late repsons, thanks all for the good input!

It looks like the flywheel I was offered has gone so I need to find something else. A lot of talk about the Aasco alu-wheel. I also realize that I want a sprung clutch, to mitigate the ratteling. This car is mainly a street car but I want it to be competetive at the track too.

So, if I would go with the Aasco, do anyone know a sprung clutch that would fit? My car is the 986s 2003.

Also a question to yoou gues who responded about lifting heigt, the 20", do you mean the total clearance so that 20" jacks would be enough? Or do I need to lift it 20" higher than how it stands with the wheels on? Stupid questions I guess.

I know that it´s an increased risk, but wtf..

[BYprodriver]

Originally Posted by Hasbro

Not sure what lump the op has but I believe there is a thread on this forum where Jack Raby said the 2.5 is pretty much ok at handling the resulting harmonics from a lwfw, whereas the others required more balancing attention. Anyone have opinions about that?

The longer the engine stroke the more stress load on the engine parts, & greater need for the parts to be balanced.

[maytag]

Originally Posted by BYprodriver

The longer the engine stroke the more stress load on the engine parts, & greater need for the parts to be balanced.

which balancing is done internally... not by a dual-mass-flywheel. how you gonna balance with a mass that isn't always in the same place relative to the crank??

[ike84]

I think he's asking about the dampening effect, used specifically in conjunction with light weight single mass flywheels. I don't know anyone who has specifically installed this in a 986, but but the theory is sound. Many engines use the crank pulley as the harmonic damper, I don't see any reason why this wouldn't be a good insurance policy if going that route.

Sent from my SM-G970U1 using Tapatalk

[jaykay]

Yes, correct. I was after the damping function performance. The dual mass does some of this correct? Anyway it would seem this added protection....very pricey at that