Air filter box info and mod
05-26-2007, 08:44 PM
#11
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2 of the 3 are same on A4 and S4
the fresh air at front near grill and the secondary source at side of airbox into fender.
the "flap" or butterfly may or may not be for the high rpm/high speed condition, but if pulling hot air, could be for drivability during warmup. just a guess, but i cannot see hot air intake helping under the high rpm scenario. it would seem to have the opposite effect.
the "flap" or butterfly may or may not be for the high rpm/high speed condition, but if pulling hot air, could be for drivability during warmup. just a guess, but i cannot see hot air intake helping under the high rpm scenario. it would seem to have the opposite effect.
05-27-2007, 04:09 AM
#14
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For performance on a NA car, adding some hot air is prob. still better than air-starved.
IMO the car could benefit from a well-designed aftermarket CAI solution. I didn't think that before.
05-27-2007, 04:20 AM
#15
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You're welcome. It sounds so sweet, I wouldn't want any more exhaust noise.
The car screams like a banshie. The intake sound is incredible, more F1-like.
The S4 crowd could pull the airbox and cut a hole in the front/bottom. Chopping up the airbox is a common performance "trick" in certain applications. But wait - don't do it - unlike the rs4, A4/S4 guys have some aftermarket CAI choices...
The S4 crowd could pull the airbox and cut a hole in the front/bottom. Chopping up the airbox is a common performance "trick" in certain applications. But wait - don't do it - unlike the rs4, A4/S4 guys have some aftermarket CAI choices...
05-27-2007, 07:22 AM
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the main snorkel tube and small side tube on fender are there on B6/B7 A4 & S4
the fact that the addtl flap feature in the RS4 airbox has a small snorkel opening right next to exhaust manifold should tell you something about its purpose. otherwise it would be a direct feed from elsewhere.
05-27-2007, 07:28 AM
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yes, if it was air starved
the fact that it's air feed is at or near a heat exchanger really sounds to me like it's purpose is to draw warm air from exhaust manifold as quickly as possible, and this points to improved warmup/cold drivavbility purpose. that method has been and is being used on many cars.
05-27-2007, 07:33 AM
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Also
my guess is that it's closed after warmup, to prevent hot air from being drawn in and fouling the fresh air supply(s). Any way to determine when and under what conditions that flap opens?