Air filter box info and mod
05-26-2007, 03:06 PM
#1
AudiWorld Super User
Thread Starter
Air filter box info and mod
The air filter box is a very interesting animal in the RS4. Air is supplied via no less than three paths:
1) cold air comes in the front of the car via the obvious intake ducting.
2) Air (temp. unknown) is drawn from above and behind the right wheel via an intake duct that follows the fender, underneath the inner fender, and dumps air into the box via a port on the right (outer) side of the airbox.
3) The power flap. This is a 3" vacuum-operated butterfly valve that is (reportedly) operated by the ECU when the motor exceeds 5000rpm or vehicle exceeds 200km/hr. It draws underhood (hot) air from an air horn immediately in front of the airbox, and behind the heat exchanger that's visible through the right foglight area. There is no room in there to route a 3" cold air supply line.
The three intakes can be seen by pulling UP on the ducting that's visible coming out of the top of your airbox. Tip: After you're done peering down into your airbox, be sure to clean your pre-filter.
So as an experiment, I removed the 3" butterfly. Then, I figured as long as the bumper was off, I might as well oven-bake the headlights and remove those HIDEOUS orange MDOT/NHTSA corners. Ahhhh. I feel much better now.
Cheers. I'm off for a burger and a beer and listen to some intake howl.
1) cold air comes in the front of the car via the obvious intake ducting.
2) Air (temp. unknown) is drawn from above and behind the right wheel via an intake duct that follows the fender, underneath the inner fender, and dumps air into the box via a port on the right (outer) side of the airbox.
3) The power flap. This is a 3" vacuum-operated butterfly valve that is (reportedly) operated by the ECU when the motor exceeds 5000rpm or vehicle exceeds 200km/hr. It draws underhood (hot) air from an air horn immediately in front of the airbox, and behind the heat exchanger that's visible through the right foglight area. There is no room in there to route a 3" cold air supply line.
The three intakes can be seen by pulling UP on the ducting that's visible coming out of the top of your airbox. Tip: After you're done peering down into your airbox, be sure to clean your pre-filter.
So as an experiment, I removed the 3" butterfly. Then, I figured as long as the bumper was off, I might as well oven-bake the headlights and remove those HIDEOUS orange MDOT/NHTSA corners. Ahhhh. I feel much better now.
Cheers. I'm off for a burger and a beer and listen to some intake howl.
05-26-2007, 03:35 PM
#2
We have flaps on our fender port...
and I always removed mine. I also remove the sound deadening "skeleton" that is in the box to provide smoother surfaces...
from an FSI car I had...
<img src="http://img.photobucket.com/albums/v714/bhvrdr/Airbox-1.jpg">
from an FSI car I had...
<img src="http://img.photobucket.com/albums/v714/bhvrdr/Airbox-1.jpg">
05-26-2007, 05:09 PM
#4
AudiWorld Super User
Thread Starter
To get to the flapper valve, yes. And OMG, does it sound GOOD.
I now believe the valve was put in basically for noise abatement. The intake howl is very much more noticable. Forget about any civility or refinement when opening up the throttle. Holy shibby! I'm sure the motor is diggin' the extra air. I always thought the intake snorkel on top was waaaay too small....
<img src="http://pictureposter.audiworld.com/109574/flapper.jpg">
Weight reduction:
<img src="http://pictureposter.audiworld.com/109574/flapper2.jpg">
<img src="http://pictureposter.audiworld.com/109574/flapper.jpg">
Weight reduction:
<img src="http://pictureposter.audiworld.com/109574/flapper2.jpg">
05-26-2007, 05:14 PM
#6
That one is from a 2.0T FSI. It's the only pic I could find...
but I gutted the skeleton from my 1.8t and S4 as well. Did you see the sound dampner and skeleton in there? It looks like it is the bottom of the box under the filter but you can rip it right out.