Open Air Filter Through Empty 'stock' Filter Box

Varun Patrick

Registered User
I own an Audi A3 1.4 TFSi (125HP) and I am currently looking to switch out the stock air filter for an open air filter system. I have searched through many forums and pages but have not been able to find an answer to this question: Is it alright to remove the stock air filter from the filter box, and connect the cone air filter to the box directly from the outside?

The air will technically be channeled from the outside, into the open air filter, travel through the empty filter box and then into the engine.

Theoretically, it appears that there is not difference being made, just that the stock air filter box will store some reserve fresh air? Has anyone here done this and can advice me if this is a good idea or not?
 

k.lockU2

Registered User
Not sure on the A3,
however I did this on my A4 v6 with no problems at all ... I left the bottom box in situ.... and tried without it also ..only to replace it ... I found
This this created more of a vortex around the K&N filter ... the fitting bracket needed a bit of fettling for a better position ... I also found the funnel ( tunnel ) was best kept in ... I widened it at the entry point simply by cutting the grill with a dremel just under the hood ...
 

Varun Patrick

Registered User
There's no way a come air filter like a K&No is going to filter like the original , isn't Dubai , dusty ?
Dubai sure is dusty. A week after a engine cabin wash and the cabin is filled with fine sand again. But I am planning to get a filter wrap bag along with the filter.... Though I doubt it will keep the finer grains out?

So you suggest i stick with a dry filter rather than an oil based one? Probably consider a foam filter?
 

Varun Patrick

Registered User
Not sure on the A3,
however I did this on my A4 v6 with no problems at all ... I left the bottom box in situ.... and tried without it also ..only to replace it ... I found
This this created more of a vortex around the K&N filter ... the fitting bracket needed a bit of fettling for a better position ... I also found the funnel ( tunnel ) was best kept in ... I widened it at the entry point simply by cutting the grill with a dremel just under the hood ...

And also... technically, the added vortex inside the stock filter box should help cool the air a little bit too right? I'm just grasping here theoretically. lol. Have no idea how it translates and I don't want to be spending money on a loss of performance. Especially in a city as hot as Dubai.
 

alpesh26

Registered User
Take the stock air filter out and tap it out onto the floor, you'll soon see how much sand it stops getting into the engine. I did this on my Cayenne when I was living in Abu Dhabi. Personally, I would keep the stock filter, I don't think you'd get a noticeable difference with the filter system you're looking at. I'm not an engineer though lol
 

k.lockU2

Registered User
I didnt realise your location ... I'm in the uk so no dust or sand .... I would keep to the factory if I were you in that case . yes it would allow a higher cold air flow rate , " but " it would also block up at a far quicker rate . Reason being you clean them with an oil based coating this would give you the opposite goal ... starving your mass air flow sensor .
 
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