I would like to run the K & N filters without the box if possible.

 

Michael - juste a question:
In principle, if the path of air from the plenum is beginning to "tight", it can take the pressure of the air filter which increases with speed. If we make these holes, you lose this phenomenon because the air pressure will "lose" in these holes. What do you think?

 

All you are doing is allowing the intake to get more cold air.

 

Ok, but the speed of air is important too

 

It can't affect the speed on the air.

 

I think yes, more than the vehicle is faster, the air pressure increases in the intake passage of air flow so well. In fact, the real question is whether this rate is higher or lower than the aspiration of air through the plenum at full load. For my 996 TT, we had made a calculation and we had to change the air intakes of my GT2 spoiler to put the air box pressure constant. And my tt had over 500 horses.

 

I had a supercharged M3, that I built. I used a K&N filter with no box. The filter was less than 1 ft. from the ground behind the front bumper.

Your problem on the TT sounds like an air flow problem, not a problem with getting too much air. I have never heard of any problems allowing the air filter more cold air. In fact, they make cold air intakes specifically for that purpose.

 

The "N400" or AM Power Kit has a flap that opens in each air box at around 4500 RPM. I am not sure about pressure but I personally do not think the AM air system is that complex - I think they simply tried to bring in cold at the top and ran it down to the airboxes because of the shape of the enclosed bumper and radiator space - all very tight. Probably a big discussion between design and engineering. I did notice on the N400 there is an additional opening in the nose (actually 2 down low, on each side) - since I have never actually seen an N400 in the US I am not sure if this would be to let additional air into the air boxes or for additional brake cooling or both. I do know from experience both are needed for this car on the track - more cool air to the air intakes and to the front brakes/rotors.