i thought knock sensors were piezo, ie, they actually listen for a knock sound which will trigger them ... ?

I had heard of instances where the LWFW can be made to work if you tore the engine down and balanced the crankshaft with the intended fly wheel. I am not sure how you would account for all harmonics this way. Was not aware that the knock sensor used crank speed....wow

Way back when I first got my S, I was I interested in a LWFW to reduce the huge cantilever load on the crankshaft....being worried about the RMS and crank carrier loads ....live and learn

They detect excessive vibration which is why stiffer than stock mounts can be interpreted as detonation also.

sound = vibration. i can't help but think ecu's are sophisticated enough to figure all that out, otherwise that death metal i'm always playing would be messing with my timing. i'm no expert on this, but a quick google tells me that the ecu reads two signals - average and peak, and only declares knock when the difference between the two exceeds a certain threshold in order to ensure that it isn't reacting to background noise. they are also frequency specific; ie. designed to 'hear' knock specifically and not just any bang or rattle. so, you would have to overcome at least two checks before a lightweight flywheel or bad engine mount will read as knock.

further, the guys who would notice the effects of pulled timing the most - cup cars, etc., are all running factory GT3 RS lightweight flywheels and, while i am sure they have go-fast ecu maps, i doubt they run different/more advanced knock protocols.

AASCO and Tilton! Kidding of course but this is a custom option from AASCO for the Boxster S.

http://i1089.photobucket.com/albums/...m/cae3f28f.jpg


I do actually have a different ECU and knock control on the car the Tilton is on. It also has semi-solid trans and engine mounts and data logs on knock readings that don't seem to be a problem. However, I ran the Boxster spec AASCO flywheel and clutch package just like the dozens of other cars on track every weekend with stock ECUs. At least we could all be ignorant and easy to beat together and enjoy the same koolaid afterwards.

Either way, I just got myself a Boxster for every day driving and the first time the trans is pulled the Spec clutch package will go in. If for nothing else, the car is more enjoyable to drive with quicker rev matching. People enjoy driving and their cars for different reasons so the right answer may not be the same for everyone...

As a somewhat non-related data point. I was told to worry about all the things that are being discussed in the thread when I chose to install a solid flywheel in my GF's MCS. While not a light weight unit per say, it is not as heavy as the stock DMF. I guess that I was luck as none of the horror that was predicted came to pass... It works beautifully. I only have about 10K on the install, but so far so good...