3.0 TDI Airbox Mod


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Jan 17, 2017
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Hello everybody :peace:

After reading through a lot of threads I decided to try to modify the stock 3.0 TDI airbox like others did.
My car is a Audi A5 3.0 TDI Sportback from 2013 (180 KW; engine code CDUC)

A lot of A5 drivers wrote that the stock airbox is sufficiently dimensioned for allmost all driving situations, but i would like to check what is the difference of these kind of modifying. It was really easy to accomplish this kind of work - in short form I removed the "buttfly valve" from the bottom of the airbox and cut the scoop out to achieve a direct air flow to the airfilter.

At first I removed the stock airbox and took some pictures. The snorcel is not allways assembled on the stock airbox, this depends on the country i think. The snorcel is located under the left side front headlight.




On the last picture you can see the "butterfly valve", which is vacuum operated and opens at a assigned rpm to let more air flow into the airbox. At low rpm´s this valve is closed to reduce the intake noise and to prevent that dirt gets into the airbox I think. With a flathead screwdriver you can easily unclip the valve from the acuator. So there will be no error code on the controller, because the actuator is still working. Then connect the snorcel and that´s all about the "butterfly valve".


Then I removed the "scoop" from the intake box. This scoop should prevent incomming snow to direct hit the airfilter. I´ve read in other forums that this should be no problem - we will see :grin:
After cutting out that triangle just put it togehter again, assemble everything and you´re done.

Stock view with scoop:

Just clip the scoop out and then you can cut:

Airbox fitted again in the car:

Insert the airfilter with the airbox lid. There you can see that the air can directly flow on the airfilter:



After a short test drive in my oppinion you can now hear the intake a little bit louder, a nice "breathing" I think :laughing:.

I have logged 2 short drives with the "torque pro app" via OBD bluetooth adapter (1 stock & 1 modified) and I have monitored the air intake temperature and the intake manifold pressure. Now I have to look if there is any difference between the stock an modified airbox.

This kind of mod is realy easy to assemble, costs no money and the engine bay & the intake looks still totaly stock (because everything is covered).
Sure it maybe will be better to change the stock airfilter to a aftermarket filter (e.g. pipercross cone filter or any other) to get more air into the engine. I´m a little bit doubtful if with a "sport air filter" there will be more dirt particle going into the engine (that´s what you read in allmost every forums - "bla bla bla this will destroy the MAF...).

I´m sure that this mod causes not +10 hp or + 5 Nm torque, but the sound is more powerfull and I think the engine could now breathe a little bit easier.
In regular intervals I check the airbox and remove any leaves or dirt and use a vacuum cleaner to clean the airfilter. And I also chang the stock airfilter in regular intervals (e.g. every 10k - 15k km).

Any suggestions or comments are welcome :wink:

Greetings from germany :trafficlight2:
Jun 21, 2010
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Just copied part of your mod and removed part of the scoop to deres trick air flow to the filter. Couldn't get the connector off the vacuum sensor so left the valve for now.

The bit that puzzles me is why there isn't an opening at the front of the trim at the top of the engine to allow air in between the bonnet gap and the grill. Did you ever consider either drilling holes or cutting an opening into this to improve things further?