IainM

only if you run without an air filter

judging by the crap on my air filter, I would also guess that this system prevents clutch dust from gumming up the splines on the clutch asst, prolonging a smooth clutch action.

id rather change an air filter than remove the tranny

pp000830

Actually I noticed gray soot completely covering the MAF Sensor element when I cleaned it at 80K miles and also coating on the upward-facing fins of the engine cylinders behind the engine blower. I was always puzzled about where the smooth even grey coating came from until I looked at the clutch dust deposits accumulated on the filter in the airbox Then I realized it looked like tens of thousands of miles of clutch facing dust deposits. It also suggested that the air filter even if properly installed still lets some quantity of the clutch dust through.
Andy

Macs993

I recently noticed the flex hose going into to clutch bell housing was shot when I was changing my oil. I spoke to an older dealer mechanic who worked on 993s and he explained to me that it helps to cool and get the debris out of the clutch by pulling fresh air in and then out the vent via the suction created at the airbox. I replaced the flex hose. I noticed that my air filter became dirty along the bottom rear edge where the vent hose comes into the air box. My guess is the Porsche engineers had a good reason to add this venting system. I would rather see that junk on my air filter and change it regularly than have it build I up in the clutch, in addition to the added cooling, especially in my hot climate. It is probably better not to use a reusable air filter that may not be as dense with this vent. The stock Porsche filter is quite dense and should catch the dirt. My MAF sensor is clean.

Meenrod

That's all well and good for you guys with OEM airbox but as I stated in the OP I have had to remove mine due to the supercharger install. I'm trying to figure out whether to 1. Block it 2. Mesh grille it 3. Leave it venting to K&N.

Meenrod

Judging by the crud all over my K&N it doesn't need an airbox vacuum to operate. It's doing its intended job just fine with a cone filter.

IainM

Then I’d mesh cover it at the tranny to let dust out and keep out critters.