chsu74

New controversial topic:

There were threads mentioned that installing LWFW, compared to the dual mass OEM, would upset the balance the M96 engine leading to failure. If a LN bearing was installed, because it makes sense as a while you are in there mod, would the LWFW be a safe mod?

Tippy

The LWFW doesnt upset balance of the motor, it reduces harmonic dampening causing more vibration to be transmitted through the engine components.

If anything, you will be safer after the IMS bearing with a LWFW or factory dual mass.

sandersd

I've read if a LWFW is installed it is wise to have the crank/FW assembly balanced together to prevent excessive vibration which could lead to early failure.

goliver

Ive read on here that you have to use a specific oil in the trans to calm down the noise that occurs in the gear cluster due to less dampning.

redridge

I see what your next mod is.... getting ready for the Glenn are you?

Mfletch

I love my LWFW. I highly recommend this mod for the guys that don't mind increasing the sporting nature of their car. If you are worried about vibration issue, talk to Randy Aasco (the manufacturer) about it...he will tell you about all the race teams that use their product. I read every post on the subject for over a year, before I made the plunge. The gear noise is not bad. You really only notice the increased noise with the windows down and the transmission in neutral.

Ubermensch

I'm not sure a race team using a LWFW is a very convincing argument for street use. Most race teams are willing to trade performance for some longevity since they rebuild engines more frequently than the average street car owner would be comfortable with.

Jake Raby

Failures associated with the LWFW install do not share the same failed parts as that of an IMS bearing.

The failure we have experienced with the LWFW has been crankshafts broken in half, in these engines the IMS bearing saw no failure at all.

Crankshaft failures that have occurred with the LWFW rarely occur in street cars, all but one of the failures I have examined came from full time track cars or DE cars that see a lot of track time.

Gretch

Man, that ain't pretty!

drbooba1

In all fairness we have seen crankshaft breakage in engnes with the dual mass as well, and in the earlier models the dual mass has bent the crank enough for the ring gear to touch the inside of the bell housing. The factory RMS checking tool that the dealer uses measures the out of round condition of the crank to the case. As the out of balance is a buckling that starts at the crank pin connection on the crank, so when you use a LWFW despite the fact that your car feels like a race car always observe the manufactures RPM limit and don't overspeed the motor.

regards

ivangene

WTF!!!

The crankshaft can break in half??

I swear, I will not be sleeping this year either!!!

(I know my car is NOT a track car, or LWF but holy sheeeet)

chsu74

The next project, when the clutch goes, is LWFW, LN Bearing, upgraded AOS and on the fence with (Plenum?)...

Pac996

This is more of a heavy gas pedal, not a light weight flywheel

A LWFW gives you faster revs sure. But the common one helps maintain the rotating mass and not throw more pressure on the engine. The dual mass helps absorb and apply rotating mass weather going up or down in rpms while shifting. Considering the 911 can't be shifted lightening fast I don't see the LWFW as much of an integral part of performance except for getting the weight of the car down. Although I think it can help to destabilize or shift the chasis around faster for managing the contact patchs for cornering. All in all if you aren't a master of the craft a LWFW is just bling bling making it so you can wind it faster out of gear. Maybe....maybe not. What do I know, I'm just an old man hehehe.

Apex996

A LWFW is a good mod to employ in an engine that is used extensively as a track car. However the M96 has no crank damper (until the 3.8L)...so the FW provides this function. If you research crank dampers for other engines you may see more on the subject such as; Loss of power, harmonic vibrations, bearing life, ignition issues... faster revving, but some loss of power is actually common.

If a light weight flywheel, (even a perfectly balanced one from a top notch manufacturer) is bolted to an engine without dynamically balancing the entire assembly ... you may be playing with fire. Or you might be ok and the engine may not experience any failures. On the other hand.... if the minute changes in balance don't 'line up' in your favor.. you may get what Jake has posted above. The Porsche crank is made from powder... powdered metal. It's not a forged GT3 crank. Caveat Emptor.

I have experience in this area on non-porsche engines. Not trashing the LWFW idea, just saying it needs to be employed correctly. Via full dynamic balancing...w/ clutch also.

It's interesting to see Pac996 describe the 996 shifting like lightning... I think my 2 gearboxes have both shifted like a truck. I'm on shifter console type #3 and gearbox #2 in my attempts to get better shifting. Hmmm. Spring is in the air... getting track fever already

juankimalo

Sorry but my english isn't good enough to understand the acronym "LWFW"

Could anyone explain me the meaning please?