The BMW questions you were afraid to ask.

[Venom]

Here's a thread where we can leave aside the assumption that we all know everything about BMW's and the mechanical or other aspects about them :hehe!:. As they say there is no such thing as a stupid question!

So have no shame and thou shalt not judge! :smiling:

I'll start...em..carbon air boxes....how exactly do they work. Nice, noise, light weight but what is the science behind the air flow that increases HP and justifies the huge price tag? :huh:

[Peter-E36]

Nothing off the top of my head, but I will prepare a big list for tomorrow

[Smokey Bear]

I would assume the airbox is designed with wave tuning in mind. Just like the trumpets length and diameter the airbox will have an effect at what engine speed the air resonates perfectly.

By having an airbox which is not tuned to the trumpets then the system will not be as efficient and will have frictional losses an will not resonate properly I woud think.

I never studied carbon air boxes but my project in college was variable length intake manifolds and they basically worked on the above principal but oddly enough only worked at full throttle.

Here's a previous study. As it's an extension to the throttle body's the airbox would work in a similar way.

http://www.emeraldm3d.com/articles/cat/projects/post/emr-adj-length-intake/

There is also the fact that it provides less of a restriction to the intake of air.

[Chrispyfish]

I think the main thing with air boxes is they hold air in them so when air is needed all of a sudden (acceleration) the air is there ready to go, quicker induction. The reason they are carbon is more then likely just for weight saving, adding a big plastic box would defeat the purpose of the quicker acceperation, the weight would probably counteract that added speed

Hope that makes sense.

Japs done one few years ago called "arc air" for Vtecs, 4-AGE engines etc but they went out of business for a while, crazy prices now for them secondhand. Think they are back in business but not making the small and older stuff anymore.

Sorry on phone so ignore spelling etc

[John_D]

If it's the CSL airbox your thinking of there's another important factor, Alpha-N .
This does away with the MAF afaik. I guess without the MAF there is less obstruction in the airflow.

[Venom]

So less flex, more air flow and a combination of tuning and interior design? Thanks men

Who's next to the confession box so?:hehe!:

[nigzcurran]

I don't know what a tracker mortgage is?

[Valdelisbmw]

Sorry less flex ? As aluminium manifold?

[Venom]

Sorry less flex ? As aluminium manifold?

I think he said less flex than a plastic box.

[Gitzer]

Would having a cone filter surrounded by a carbon open ended box have a negative effect on performance and response if the car has no additional map for it?
Also as far as i can see there is no cold air feed to it.