diy E90 Air duct inlet

[LYFGP]

So I was doing a little cleaning yesterday and noticed that the one side of the air inlet duct is closed.

I was thinking of doing a little “mod” and opening it up.
Will it make any difference? Is it worth it?

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[LYFGP]

No one done this yet?

 

[naren512]

to be honest, i have not checked mine. will try this weekend

 

[AshG108]

My LCi e90 320d also had the same and I removed it...also had K&N air filter already so perhaps placebo effect, car felt like it breathed better but i have ono concrete proof of that though.

 

[LYFGP]

Thanks gents.

I guess it's wort a try then just to do it and come back and give my opinion then.

 

[Nukleuz]

I think BMW's multi million dollar R&D department would have tested that option, and decided
to make it that way for particular reasons.

I would leave it be.

 

[Sleepa]

I am not sure about the above.

Can only assume it increases airflow as the 30ds ones are completely open both sides.

However I know the below works well.

Logged no heat soak, gives good airflow gains +20% with stock intake pipe.

 

[LYFGP]

Update: I've cut them open last night and went for a test drive.
There's probably no difference at all besides a bit more air intake, but in my mind my car feels faster

@Sleepa I guess the 30d needs all that air more than the 20d then?
A friend of mine actually has the same filter on his 20d e87 and also mentioned the increased gains and mentioned some stustustu sounds (Video included on whatsapp)

 

[Sleepa]

Update: I've cut them open last night and went for a test drive.
There's probably no difference at all besides a bit more air intake, but in my mind my car feels faster

@Sleepa I guess the 30d needs all that air more than the 20d then?
A friend of mine actually has the same filter on his 20d e87 and also mentioned the increased gains and mentioned some stustustu sounds (Video included on whatsapp)

By cutting them out I honestly cannot see it hurting anything.

Why they block them on the 20d and they are open on the 30d? No clue. At the end of the day you can only get so much volume of air through the filter anyway?

Glad to hear he's enjoying the filters. They are epic!

 

[EthanJappie]

I am not sure about the above.

Can only assume it increases airflow as the 30ds ones are completely open both sides.

However I know the below works well.

Logged no heat soak, gives good airflow gains +20% with stock intake pipe.

What size air filter did you use? Thinking of doing the same on my 30d

 

[Sleepa]

What size air filter did you use? Thinking of doing the same on my 30d

76mm

 

[EthanJappie]

76mm

Thanks bro. Where did you get your filter if you dont mind me asking. Really like the look of it.

 

[DarrylvanNiekerk]

I did a little research on this a short while back as I was interested in doing the same to my car.

The way the air flow is designed is to create a proper flow and swirl of air through the MAF so the car knows how to fuel and set timing etc. By cutting open points or adding a cold air filter you effectively smooth out the airflow and the MAF battles to get proper readings. This can have a negative effect on your performance but the change in sound is a placebo effect.

If you want to change your airflow then ideally you should put in an aftermarket chip to account for variables the computer wasn't made to do. Without this the car sets itself to basic settings and tries to make do with info from other sensors. Long term you will probably waste fuel and just make more noise.