2.8 air box mod.
04-25-2002, 04:10 AM
#1
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2.8 air box mod.
I did this a little while ago but haven't posted it yet. This is similar to the europeanspeed.com airbox mod but the 2.8 has a different design which I believe makes this mod better for it.
1. Remove the airbox completely.
2. Unscrew the screw that holds the mesh prescreen. Remove the screen by sliding it up and out. (These really restrict airflow, especially if it is full. Removing it doesn't hurt anything since I know at least the 96 does not have it).
3. Down at the bottom of the airbox is a spring loaded flap held by 2 screws. This opens up under heavy throttle and high revs because of the vacuum caused by the increased use of air at high rpm. Remove it. All you are doing here is allowing more air to come in all the time instead just higher rpm.
At this point you can reinstall your airbox. I felt a pretty big difference with just this little bit of work. Throttle response is better and the rpm drop during shifting is smoother.
However I wasn't finished. After a little friendly persuasion, I removed the airbox again and drilled 1/4" holes in the inner fender well inside where the foam surround on the bottom of the airbox sits. I drilled about 20 holes in a grid pattern to allow more air in (this air is cold too) I also drilled one or two holes down where the foam surround would be at its lowest to drain any possible accumulation of water (more on this later).
Test drive time. The holes really made a difference. I don't think this is a placebo effect because I have had some people ride before and after the mod and they can feel a difference. At the time of their comment they did not know about my tinkering. My wife is one of them and made a comment about how much smoother it felt.
Now. First rainstorm post-mod was a doozy. I was worried about the water coming into the airbox from the wheel well. I took it apart and looked inside the airbox afterward and it was well and truly dry. I believe since the holes are inside the line of the tire that the tire isn't flinging the water into the holes.
I would say for the time spent on it and the lack of money spent on it, this mod is worthwhile. Audi seemed to design the 2.8 box pretty well with few obstructions and good flowthrough. Removing the prescreen cleaned up the last of the obstructions and removing the flap allows more air in. A K&N filter to top it off is worthwhile.
I would recommend this mod to other 2.8 owners especially if you don't want to get a cone intake (was doing research for that when I found this mod)
I think this mod only works on the 30v engines. I tried to do it on a 96 A4 for a friend and the airbox did not have the screen or the flap. However, the mounting points and the shape of the box were similar to the 30v so it might be possible to use a 30v airbox in place of the 12v.
Remember as always, you are doing this mod at your own risk. I accept no responsibility for damage to your vehicle or yourself. (standard liability clause)
Good luck.
1. Remove the airbox completely.
2. Unscrew the screw that holds the mesh prescreen. Remove the screen by sliding it up and out. (These really restrict airflow, especially if it is full. Removing it doesn't hurt anything since I know at least the 96 does not have it).
3. Down at the bottom of the airbox is a spring loaded flap held by 2 screws. This opens up under heavy throttle and high revs because of the vacuum caused by the increased use of air at high rpm. Remove it. All you are doing here is allowing more air to come in all the time instead just higher rpm.
At this point you can reinstall your airbox. I felt a pretty big difference with just this little bit of work. Throttle response is better and the rpm drop during shifting is smoother.
However I wasn't finished. After a little friendly persuasion, I removed the airbox again and drilled 1/4" holes in the inner fender well inside where the foam surround on the bottom of the airbox sits. I drilled about 20 holes in a grid pattern to allow more air in (this air is cold too) I also drilled one or two holes down where the foam surround would be at its lowest to drain any possible accumulation of water (more on this later).
Test drive time. The holes really made a difference. I don't think this is a placebo effect because I have had some people ride before and after the mod and they can feel a difference. At the time of their comment they did not know about my tinkering. My wife is one of them and made a comment about how much smoother it felt.
Now. First rainstorm post-mod was a doozy. I was worried about the water coming into the airbox from the wheel well. I took it apart and looked inside the airbox afterward and it was well and truly dry. I believe since the holes are inside the line of the tire that the tire isn't flinging the water into the holes.
I would say for the time spent on it and the lack of money spent on it, this mod is worthwhile. Audi seemed to design the 2.8 box pretty well with few obstructions and good flowthrough. Removing the prescreen cleaned up the last of the obstructions and removing the flap allows more air in. A K&N filter to top it off is worthwhile.
I would recommend this mod to other 2.8 owners especially if you don't want to get a cone intake (was doing research for that when I found this mod)
I think this mod only works on the 30v engines. I tried to do it on a 96 A4 for a friend and the airbox did not have the screen or the flap. However, the mounting points and the shape of the box were similar to the 30v so it might be possible to use a 30v airbox in place of the 12v.
Remember as always, you are doing this mod at your own risk. I accept no responsibility for damage to your vehicle or yourself. (standard liability clause)
Good luck.
04-25-2002, 09:18 AM
#3
That won't work at all....
in this forum because you haven't provided any pictures 
Yes, that screen is restrictive - in fact on 1.8T's and 2.7T's, you can see it being sucked in. However, it is extra insurance for a car that lives under trees or road debri a lot with the owner who'd rather drive it than maintain the car regularly. For performance, a lot of things can be modified or taken off.
Yes, that screen is restrictive - in fact on 1.8T's and 2.7T's, you can see it being sucked in. However, it is extra insurance for a car that lives under trees or road debri a lot with the owner who'd rather drive it than maintain the car regularly. For performance, a lot of things can be modified or taken off.
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