Hi All...reading a porsche book and read some interesting takes on upgrading the air filter system in the engine bay with a K&N cold air design or otherwise...

Read on...info is interesting...hope to not start a debate...

"It's a complete waste of time installing aftermarket air filter assemblies on the standard full water cooled 3.4 and 3.6 liter M96 engines...Over 90% of these engines are fitted with electronically controlled throttle valves, and the DME (ECU) decides how much air is going to be let into the engine, not the driver."

Taken out of Porsche 996, the essential companion...

It does state that it may help with the noise...

 

It makes sense.

 

Couldnt you compensate this with tuning. If you could tune the throttle valves to allow more air in via a cold air intake wouldnt this net a power gain?

 

The engineer in me forces me to chime in.

When cruising, or at "partial throttle", where you're only asking for a percentage of the engine's maximum power, the combined pressure loss across the filter and butterfly (in the throttle body) will be a constant. (The butterfly will be more open with a more restrictive intake/filter, and more closed with a less restrictive one.) In this mode, the effect of a performance air filter/intake on engine power output is pretty much nil, although it may sound better with an aftermarket intake.

BUT--and this is an important but--when you floor the fun pedal and ask the engine to produce maximum power, the butterfly will open wide and produce effectively zero pressure loss. In this mode, the pressure loss across the air filter/intake will directly affect the amount of air delivered to the engine: less pressure loss = denser charge = more air. More air means you can burn more fuel which equals more power.

The writer of the "essential companion" may be trying to say that, for the vast majority of drivers, an aftermarket intake/filter may offer no real performance advantage. Unless one races or tracks their car a lot, this is probably true. But he/she is totally incorrect to say that they are a "complete waste of time".

 

I think the book also mentions damage to the mass air flow sensor caused by oil on filters such as the k&n one

 

Just my .02 but if you have ever installed a K&N or equivalent hi flow filter in your car you will instantly hear that wonderful noise it produces that makes me not care so much how many extra ponies I am getting. You have to experience it first hand to appreciate it and once you do the occasional MAF you hear about getting ruined is a risk you’ll take. Personally I think many of the reported MAF issues stem from mishandling or age of the part but that’s just my opinion and that keeps me happy.

 

Can't agree more. Have had the K&N for almost a yr, no MAF issue.