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The only way to be 100% sure you have the larger IMS bearing on an '05 or '06 997 is to physically look at the nut of the bearing cap once you have the transmission separated from the motor. Big nut = larger bearing
The other thing you should do once you verify you have the larger bearing is to remove the seal on the IMS bearing that can be accessed once you remove the bearing flange. The IMS bearing resides in what is not a good location for a sealed bearing since it's sitting in oil - oil migrates in past the seal and washes out the grease that is supposed to lubricate the bearing, but the seal prevents enough fresh oil in to do a good job of lubrication. This is the recomendation for anyone with a large bearing car, especially if it's going to see some track time at more sustained higher RPMs as the surface speed of the larger bearing can actually get too high on a track. The only 2 large bearing failures I'm aware of happened on cars that had some track use. If it turns out you have a small IMS bearing, replace it with The IMS Solution option - if not, just pull the seal, but while you're in there for the transmission work, don't leave it alone.
My 997 C2S is supercharged and pretty close to 500 HP and using the stock clutch with no slippage or other issues. Don't do the lightened flywheel or more aggressive pressure plate material. The lightened flywheel will sacrifice smoothness and drivability, also making the car more prone to stalling when pulling away from a stop. The more aggressive friction disc material will make for very abrupt and jerky engagement of the clutch. My supercharged 928 Spyder has one of these friction discs in it and I wish it didn't as it's almost impossible to launch smoothly from a stop and that car has a ton of low down torque that the 997 doesn't have.
Combining a lightweight flywheel and aggressive friction material pressure plate is a recipe for stalling the car or looking silly leaving almost every stop light.
I also contemplated a LWF, but after research, I found that it wasn't recommended to add a part that wasn't balanced to the engine, which could potentially lead to added vibration and put an already risk-prone engine at more risk for rotational imbalances similar to failures that the IMS suffers...or something like that. Basically, it wasn't Raby approved, and I tend to follow his recommendations.
My clutch started acting funky last week so I pulled the transmission on Sunday. It is an 07 4S so that was a little extra fun. I was surprised how good the clutch disc looked after 104k. The throw out bearing was shot and likely the source of the problem. The car sees a combination of street and track duty so I'm installing an OEM clutch and pressure plate and an AASCO light weight flywheel. I'm bolting it all together tomorrow. I will let you know what I think.
I have logged about 4,000 miles on my Aasco LWFW and I love it. Yes you will get a some chatter in neutral with clutch engaged (after warming up) and a little chatter up to around 2,000 rpms but I wouldn't say its overwhelming. My favorite mod to date!
They’re a performance shop so they offered some optional upgrades as alternatives to going OEM. But after lots of research I’ve decided to go with a dual mass FW. The rattling a LWFW might bring is a concern too much of a concern. I did choose the Bully stage three clutch plate over an OEM though on the advice of a close friend who says the feel off the line is negligible and the added clamping force improves performance. I’ll let you know once it’s done.
Sadly, I’ve had to postponed the work for a while as we’ve received a fair amount of snow up here and I’d rather not drive the car on salty roads.
Sorry for bringing an old thread back to life but I have 2008 C4S and thinking of doing a LWFW , new pressure plate , clutch , new Shift cables and numeric shifter. Reading all the posts about the LWFW rattle and drivability is making me questions the LWFW choice.
Do you still love the LWFW? I am in SoCal would love to know how it would be in traffic. I have a 6MT.
I hav an 08 c4s with all of those done. I love it, but I've had lwfw in previous cars... So I knew what to expect. Also, my car is heavily modded, so I'm immune to the decreased comfort. See my build thread for full mods
I never really noticed the noise until I installed the numeric shifter cables with everything else. Then, when the windows were closed, I noticed a whining sound. Online, there were ways to silence the cables. But I never bothered, as it didn't bother me after a short while
One note... Alex from Sharkwerks does not recommend the lwfw with the AWD. My car was converted to RWD prior to the lwfw. I did mine with a kit that cost about a grand. Details in my build thread
Hah, if memory serves, I sold Halo777 my old aluminum flywheel. It was on my 06 C4S when I bought it. After a few months of ownership, I noticed rattling when the car was idling. Wouldn't occur when the car was cold, and the rattling would also go away when clutch pedal pressed. I figured release bearing, but got a good deal on a complete clutch replacement package including the flywheel so everything went in, and I flogged the flywheel later - so I feel somehow connected to Halo's build lol
On another note, I also remember that I got the clutch kit from another Rennlister. He had listed the package on the classifieds, and I emailed asking if he could confirm a part number or something, not expecting him to have the parts still for sale as the ad was several years old by the time I contacted him. Next thing I know he's shipped the whole thing to me, and just asked me to pay him later! What a guy. That's Rennlist for you.
Yes, I think you are right! Which demonstrates perfectly, that this is the type of mod that one person may love, and another dislike. I can give my positive feedback on the LWFW, but I cant necessarily recommend it to anyone. People have to decide for themselves, as the investment in parts and labor is not a small one.
Thanks Hallo777. Your build is impressive. I may stay off the LWFW and stick to the dual mass but I will be doing the Numeric shifter and cables along with the Fister Exhaust.
I would caution anyone against a lightweight flywheel on these cars.
Porsche flat 6 motors suffer from bad crank harmonics and the dual mass flywheel absorbs some of it (though this isn't really its primary function). A 3.8 is probably the least susceptible to crank breakage since it has a factory harmonic balancer to absorb these harmonics (though because its an elastomer damper its tuned specifically for a certain point and isn't much good if you change part of the assembly like the flywheel.) The only proper way to fit a Lightweight flywheel is with an aftermarket harmonic damper tuned for it, which nobody makes (RSS makes a damper that looks like a rebranded fluidampr i think, but its an underdrive pulley so that's a no go.) Not sure why ATI or Fludampr haven't made a stock replacement damper. Seems like there's a market for one.
I'm not saying it can't be done, many people run lwfw's on these cars, but i believe if you ask Jake Raby he'll tell you every broken crank he's seen was attached to a lightweight flywheel.
I would caution anyone against a lightweight flywheel on these cars.
Porsche flat 6 motors suffer from bad crank harmonics and the dual mass flywheel absorbs some of it (though this isn't really its primary function). A 3.8 is probably the least susceptible to crank breakage since it has a factory harmonic balancer to absorb these harmonics (though because its an elastomer damper its tuned specifically for a certain point and isn't much good if you change part of the assembly like the flywheel.) The only proper way to fit a Lightweight flywheel is with an aftermarket harmonic damper tuned for it, which nobody makes (RSS makes a damper that looks like a rebranded fluidampr i think, but its an underdrive pulley so that's a no go.) Not sure why ATI or Fludampr haven't made a stock replacement damper. Seems like there's a market for one.
I'm not saying it can't be done, many people run lwfw's on these cars, but i believe if you ask Jake Raby he'll tell you every broken crank he's seen was attached to a lightweight flywheel.
Sprung clutch is also important. I think some people cheap out and just get the LWFW without getting the right clutch to go with it.
I have the RSS underdrive dampened pulley on my 997.1 C2 for 4 months now with no issue. Battery charging is perfectly fine, same goes to power steering. What's "no go" about it?
Sprung clutch is also important. I think some people cheap out and just get the LWFW without getting the right clutch to go with it.
I have the RSS underdrive dampened pulley on my 997.1 C2 for 4 months now with no issue. Battery charging is perfectly fine, same goes to power steering. What's "no go" about it?
Correct, The DMF is to protect the gearbox, not the engine. A sprung hub clutch would take over the job of absorbing input shock to the gearbox if you got rid of the dmf.
As for the damper, charging and power steering are probably fine. PS might even benefit from running cooler. The problem is the water pump, M96's and 7's already have cylinder cooling problems that are a major contributor to bore scoring and cylinder ovality/instability. Underdriving your water pump isn't going to help this, even if it doesn't directly cause failure. (you'll notice some engine rebuilders modify the coolant passages to the cylinders to help this.) Maybe it isn't enough to matter, but i would still avoid it personally. The RSS pulley might solve the flywheel problem, but I wish they would make a stock size pulley. Maybe I should email them to ask if they will.
11-21-2016, 01:07 PM
