[JBSC]

Originally Posted by Marc Bixen

Porsche started installing an alternator clutch bearing on all manual trans cars starting with 996's. Tiptronic and PDK don't use it. The actual reason for the clutch release, and remember on air cooled cars, the alternator is behind the fan, is to prevent over-rev on high rpm shifts. Track guys will get this. What happens is that at high rpm when you depress the clutch the centrifugal spinning force of the alternator will actually cause the rpm to go up another 200-300 rpm after you push the clutch pedal and lift off the gas, thus creating an over-rev. Very common on 964/993 track cars. I've never heard of this causing over-rev type damage, but it is a little disconcerting, and does slightly slow down your shift, which equals increased lap times. Not what you're looking for. Cool innovation guys, thinking outside the box. I'm sure there are other bonuses from this also, maybe increased cooling, as the fan continues to spin at higher rpm than the engine on decel, as well as possibly slightly better fuel economy. I've thought about something like this ever since learning about the system on 996's. Thumbs up. Hope you can market it well.

Thanks, Marc. Exactly how I thought of it. Didn't know about the 996/997/991 analogy. Looking forward to seeing how their R&D progresses.