58 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHLightweight flywheel
Leading reported evidence
Check pelican parts did not see my car listed
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
I checked pelican parts did not see my car listed.
Leading evidence: 'Check pelican parts did not see my car listed' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check more information' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
Ran both on my 997 C4s but I am pretty sure they are compatible with the 996.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
He did tell me about the multiple race cars/teams that used his flywheel.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I use Revo which was the rage back in the late 2000s and one of the early software providers.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I know a good few people running LWFW with no issues at all on the 3.6 I will be fitting one to mine this year along with a Harmonically damped underdrive pulley.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
58 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T174436Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Agree with DBJoe. Why create the problem if you dont have to. If you want faster reving, all you need to do is get a good tune. They all facilitate faster reving for the e-throttle powered cars. And it will cost you less money with more benefits.
They are fine if you have the crank, FW and clutch assemply balanced during a rebuild along with properly weighted pistons and rods. Of course its also good practice to get a billet crank if its a race build.
It might help against gearbox chatter at idle but it won't replace the DMF's damping of torsional vibrations in the crankshaft itself. Which no degree of balancing of the whole assembly will do either.
M96 Its an internally balanced engine iirr.
Thinking since its a flat 6 with opposing cylinders, if all reciprocating rod & piston mass weights are equal, they cancel each other out. So when balancing crank no bob weights are needed. or external weight from flywheel or damper
But the crank pulley damper and heavy DMF are there to cancel harmonic vibration at the rpms where vibs peak, not to balance engine recip mass.
DMF is balanced all by itself as a separate entity. And its spring activated dual masses move slightly to cancel harmonics at speed, allowing them to rotate slightly independently to cushion power pulses/vibs
Above is directly related to installing a light weight flywheel and how it should be balanced integrated with the reciprocating mass.
Other things to take into considerations with a LWF are the inevitable harmonic vibrations of a flat 6 that have been known to snap cranks in pieces.
If the LWF is perfectly balanced by itself to add no external vibrations/harmonics, and a quality correct size/mass Fluid Dampener is also installed that seems to help minimize the risks of damage to the crank from a LWF.
Funny thing is, Porsche engineers decided on using an expensive DMF instead of making bean counters happy....hmmm ?
Guess we know better on what basic engine principles our engines need/work best with.
Refresh me, Why exactly do we need a LWF...?
jmo
Without much knowledge of the 911R, I do know its a Mezger design basic architecture with dry sump lubrication, without the opposing harmonic vibrations from chain drives/chains on both ends of the engine like our m96.
Can only assume if Porsche offers a LWF then the DMF is not needed for engine longevity on the 911R like it is on the m96. Maybe an option for more comfort on the R and less NVH. 911R engine is a very different animal than the bean counter m96.
But all the above is just a guess, I'll go with whatever the Porsche engineers recommend/offer and build. The engineering/R&D department at Porsche are some of if not the best in he world at developing engines if the bean counters leave them alone. Yes they do have some problems with cutting edge materials now and then, thats the price to pay for the highest performance cutting edge stuff. Just have to look at there racing achievements. I have no doubt they know a lot more than any of us by a long shot...
Get a Sprint booster. Climb under your dash and plug it in. Set it easy at first then slowly increase before going to race mode. They can go up to 10. Mine goes to 11.
My friend has 996.1 GT3 and it has single mass light weight flywheel and solid clutch plate (makes 'bag of spannes' noice at idle) from factory.
Is the Metzger engine that much different than M96 related to the harmonic vibrations - isn't both engines moving pistons and fireing in same order?
Mezger engines rattle the transmission and that's what they do unless you spring for a 997 RSR crankshaft. The obnoxious noise doesn't harm anything except your hearing. The DMF calms the rattling. I had a lightweight flywheel and went back to the DMF after 100 miles; I loved the zing of how it revved. The rattling didn't play well with my tinitus so I had to change it.
I ran a LWF for over a decade with no issues. 1999 996 C2. I wouldn’t do it for a street only car however. Since I have a throttle cable, there was no Sprint Booster option but I have not heard positive things about them on some of the other cars I have had. If it’s a track car then I’d recommend skipping it. No serious track guys that i know use it, but it may be beneficial for street driven cars. With no first hand experience with a Sprint Booster though, my opinion is fairly worthless and clearly it works for some.
There is not a single shared part between a mezger and a m96 motor. The mezgers have also been in existance since before a dmf was even a thing so the pitfalls have been worked out. I have the lwfw in my gt3ish and i barely hear it at idle but i also drive a dual disk cummins dodge and peterbilt. The noises from their transmissions dont bother me either.
Thanks, yes this is familiar to me, but am trying to understand the harmonic vibrations discussed earlier.
If the pistons move in same way opposing to each other and the fireing order is same, the hamonic vibrations should be same - weight and balancing of moving internal parts of course effect the force of the harmonic vibrations.
My guess is that the mezger crank was designed in a manor that would resist all of those harmonic issues. The parts in a m96 were built for value and efficiency with the intention of a dmf so the internal parts may not be as strong?
I don't blame you. I was skeptical. I'm pretty much a born skeptic. I could go on and on, so do some research but for sure a Sprint is orders of magnitude easier/cheaper than installing a LWFWheel. You can do it yourself in an hour or less and if your crank busts it isn't the booster that did it.
I don't understand the sprint booster rationale. All it does is step on the gas harder. It's not like the e-gas pedal can go beyond 100% open. So just use the right foot to step on the gas harder and save the coin.
The other option is to pay a little more and get a software package for $1k from a firm that knows the M96 very well which can provide the programming for better throttle response.
An example of this would be FVD Brombacher. You tell them what 996 you have and what you have on it for exhaust amd intake mods and they will send you the program for upload. Any time you add more mods to your exhaust and intake, just let them know and they will update the program and send it to you.
Plenty of other software out there from experienced companies that can do the same.
I use Revo which was the rage back in the late 2000s and one of the early software providers. Great throttle response. Heel toe shifting is a pleasure. But they are no longer in the US. Only Europe.
If I was to refresh my software, I would go with FVD.
Haha. That's exactly what I did pretty much word for word. And that's why I didn't get one for a long time. I was chasing the throttle response my Webers give on my rev happy 2.7. That thing spins when you wiggle your pinkie toe and it's intoxicating. It's one of the things a "tune" does. There's not a lot of power to gain with a tune, many have walked that path, but anemic throttle response can be reprogrammed to compensate significantly. It's a choice, driver dependent.
If you try it let us know for those who may ask later.
Mine goes to 11.
I know a good few people running LWFW with no issues at all on the 3.6 I will be fitting one to mine this year along with a Harmonically damped underdrive pulley.
it makes a huge difference to how quick the engine revs up and down.
By adding the harmonic damper (integrated in) underdrive pulley you reinstate what you loose by going to a single mass (light) flywheel and that, i.e. your way, is the way to do it IMO.
Generally speaking, not having the harmonic vibrations in the crankshaft damped will shorten its service life.
Service life may still be long enough for some but it will be shorter than WITH a means of damping.
As a side note, the stock pulley on the M96 (dont know about M96.7x) has no harmonic balancer integrated as it's a single piece rigidly bolted onto the crank. The M97 got one.
I have been running a LWFW on my 99 996 for over 20 years. I absolutely love it. Before I installed it, I did my research. The person that inspired me to do it was Alex at Sharkwerks. His first 996 project was his personal car dubbed, "Project White Shark". He did a video of his car that you can probably no longer access. The previous owner of my car had several modifications done by Sharkwerks, including a Bilstein Pss9 coilover suspension and GIAC tune. I also contacted the manufacturer of the LWFW, Randy Aasco. After talking to him, I had no concerns about installing his product (I bought mine used, so he wasn't making money on me). The only time that I ever hear the noise is at idle, with the AC turned on. I really only notice it when I'm in line at a drive through. I am building another car to track (foxbody Saleen) and I absolutely will install a LWFW in that car. I love how much faster my car revs up with the LWFW. My first car had a non syncro first gear, so I learned to double clutch when I learned how to drive. Double clutching a LWFW is a joy.
If you believe the forum sponsor's expertise (I do) on the m96, you might find old post below interesting. As they probably build more m96 engines than most anyone...
My take on LWFW...
When all is said and done, with the compatible clutch, getting the LWF balanced, adding a quality harmonic damper, you've spent considerably more than installing a oem DMF. And you've added a distinct possibility of the m96 going 'snap' in a split second rendering your m96 toast.
IMHO there is so much $$$$$ just to get our 20+ year old cars up to snuff why neglect that and jump to a questionable performance upgrade before making your m96 reliable/longivity. Fix imsb, fix defective cylinder structure, fix oil pressure instability, fix AOS hydrolock, fix cam deviation/guides/pads/actuator o-rings/small chains. Do all deferred maintenance like wP, pulleys/belts, engine mounts, expansion tanks, etc. So many thing to do to our 20 + yo cars before even thinking about performance upgrades.
Suppose when all that above stuff is done, along with a full suspension refresh, all interior working & looking acceptable, then its time to look at performance up grades imho...
Taking the potential negative effects of harmonics out of the equation...
In my 21 years of tracking the same 996.2, I have never once wished I had a LWFW on my car to go faster. What i wanted was more throttle response for heal toe shifting on the track. Software solved this perfectly.
I dont get the LWFW excitement. There is no power advantage and no advantage in a M96 over a good software package in reving. Believe me when I tell you, if I could find a way to reduce my track times with a LWFW, I would have done it.
If you want a faster car, upgrade your tires, upgrade your suspension set-up, go to a proven set of 200 cell cats, get a Guard LSD, upgrade your software to rev faster, add the UAOS T and deep sump for more oil, upgrade your brakes, and find yourself a good PCA instructor to show you how to safely balance the car and carry speed.
But I get it, sometimes there are things we prefer even though there is no performance benefit to it.
Hardtailer, I seriously doubt that I asked him that exact question twenty years ago. I do recall that I called him because I bought my flywheel used and it got damaged during shipping (it ripped through the box). He repaired it for almost nothing. When I received it back, it was rebuilt to new condition. He did tell me about the multiple race cars/teams that used his flywheel. He also told me that I would need to use a spring centered clutch with his flywheel.
Scoe911, I have always used a spring centered clutch.
Here is the reason that I initially decided to go with a LWFW....
https://www.sharkwerks.com/1999-shar...-fikse-and-ruf
GC996, "sometimes there are things we prefer even though there is no performance benefit to it"
Why did Porsche put a single mass flywheel on the 996 GT3 RS?
"Uniquely, the RS featured a close-ratio version of the Getrag G96/96 six-speed manual gearbox fitted to the base GT3 along with a single mass flywheel."
I would expect the LWFW crank life is up to the capability of the user. Comments like 'all broken cranks had LWFW' indicates that having one creates a use case where the weight of the vehicle can oppose the engines angular momentum enough to break the crank. Normal drivers won't understand the condition and unknowingly create it.
I would expect it occurs at high speed when a downshift is needed but the rev match is bad.(WAG) The better drivers never create this condition and end up with a 20yr+ life time.
Knowing what a mediocre driver I am, I'll take
@Porschetech3
advice. I don't need a 0.1 second per lap improvement.
eta: My guess at why cranks are breaking is wrong. I've lined out the guess. See post #50 below
Would be interesting to learn how many actual crankshaft failures have been found that have been caused by LWFW with sping centered clutchplate on M96 engines.
Glad you are testing it. Let us know which one you are using and what you are doing to balance everything. Tell us a little more about your 996 such as year, any other mods you have done and if its a street car and if you track it.
My 996 is a 2003 c2 3.6 with added aero parts 175,000 miles ish. orignal engine, IMS, X51 sump, 997 oil return, 997 oil pressure valve and spring upgrade, IPD 82mm inlet and throttle body.
Prep works spec Nitron road sports coil overs with 30Nm/70Nm Eibach Competition Springs (250mm length), Eibach Hollow Technology Anti Roll bar kit, GT3 coffin arms with adjustable arms. OZ Alleggerita alloys 235/40/18 f 275/35/18 rear
Stance Aircups nose lift
996 GT3 carbon ceramic brakes & MC
Equal length Manifolds with IGT sensors, 200cell cats x-pipe, valvetronic silencers with PSE retro fit
Cruise control retro fit
Last year I had it remapped and it made 337bhp and 313.6ftlb at the fly
Nice! Great to know you have a 3.6. Its a great engine!
Do you track the car? Have you done anything with software to rev faster? Also wondering if you did the Plenum and TB mod before you added the equal length headers to see if the headers made a difference?
Good to see another 996.2 enthusiast.
This is not the scenario that causes cranks to snap.
If cranks without a DMF or harmonic damping pulley snap, it is due to fatigue of the crank induced by the harmonic oscillations in turn caused by the combustion forces which vary during combustion stroke.
It happens at a load far below the failure threshold for a one-time applied load.
An example of failure due to fatigue is the metal paper clip that you can bend a couple of times without breaking but repeat it 10x and it breaks.
A sprung clutch disk does very little in this regard either. Its springs primarily reduce shock loading when it is engaged abruptly.
I've been on track afew times with it but mainly a road car. the throttle response is much quicker that stock but it don't rev up and down any where as fast as my mate Scott 996.2 aero with LWFW. He posted a clip of it on insta,
Instagram
Cool. If its an important addition to you guys then enjoy it. We all welcome the testing of parts for engine longevity. I hope you and your buddy get actively involved on Rennlist and keep us posted.
Maybe its because I have been driving my 3.6 for 23 years on the street and track, and know the powerband like the back of my hand, I gotta say that I have never had an issue with rev speed after upgrading the software on the e-throttle. Alot of it has to do with carrying the right RPM in the right gear with the right rev matching. But I am one of those guys that out of habit heel toe shifts around town.
Don't forget to let us know which one you are going to use and what balancing procedures you are going to do. We love this stuff.
FYI - I have both an Aasco LWFW and RSS dampened underdrive pulley for sale. Ran both on my 997 C4s but I am pretty sure they are compatible with the 996.
also have awe headers, if they will fit the 996
I am in Canada but can ship
I had a 14lb single mass flywheel installed in my 2001 996 C2 about a year ago and it has made downshifting much more immediate and enjoyable. No problems with takeoff and chatter only happens on very hot days but doesn't bother me at all as my x-pipe and tubi style exhaust are way louder
If your going to a LTW flywheel, at very least you need a very good harmonic balancer to replace the crank pully..
Boxer 6 cyl engines have a muti order vibration profile, it doesn't shake much, but when it does it does it intensely
and you cant feel it driving the car, Its a fairly high frequency resonance , similar to the one that can kill any 302
ford if you run it extended at about 4K rpm's, it cracks the block on the #2 Main.
I have driven 2.5 years and approximately 20K km with Aasco LWFW and center sprung Sachs clutch plate on M96 engine - which have been about 50% heavy track use and rest street use. Works real well and could'n be happier of the much faster engine response.
I did get the LWFW and clutch package balanced as a set at the local race team's machine shop.
This is a source reference. Confirm exact model applicability in the original material.
