[tsosby20]

I am wondering if there is anyway to fit in a cone style k&n filter in the stock air box rather than having the normal drop in filter? Any ideas?

[hassmaschine]

Why? It doesn't make any difference. An intake is probably the worst bang for buck mod you could do for an N52. A drop in filter is just as good, if not better (because it's cheap, and drops in, and still makes no difference).

[tsosby20]

Originally Posted by hassmaschine

Why? It doesn't make any difference.

It would be the same as having the euro air box, and the euro air box has more gains than the stock due to the diameter in the filter

[hassmaschine]

Euro airbox makes no appreciable difference in power vs a drop in for the US airbox. Both make basically no difference to a stock paper filter.

[desertman123]

Euro airbox is good for noise, looks and convenience.

Source: I got one

[inxdifference]

Originally Posted by tsosby20

I am wondering if there is anyway to fit in a cone style k&n filter in the stock air box rather than having the normal drop in filter? Any ideas?

I was wondering the same thing the other day, someone has a DIY on here.

What I gather from the end of my search is that a small cone filter in the box has a smaller surface area than your stock drop in.

Invest that money in some grill scoops or DIY ram air.

[Efthreeoh]

You have a 12-year old BMW. Take my advice, save your money for repairs.

[david in germany]

Originally Posted by hassmaschine

Euro airbox makes no appreciable difference in power vs a drop in for the US airbox. Both make basically no difference to a stock paper filter.

Euro intake does give a bump of about 2-3 mpg over the stock intake (on my wife's 328i) More efficient SHOULD give at least a bump in performance too (1-2 hp)

[rjahl]

Originally Posted by david in germany

Euro intake does give a bump of about 2-3 mpg over the stock intake (on my wife's 328i) More efficient SHOULD give at least a bump in performance too (1-2 hp)

Think about what you are saying.

A different air box and filter will improve overall engine efficiency by 10%

This is an engine with variable valve timing, variable valve lift, variable intake and a really sophisticated engine management system.

Pumping losses are already very low, the only way you see this kind of change is going from a really dirty filter to a clean one.

BMW did and could not leave that much on the table.

[hassmaschine]

Originally Posted by david in germany

Euro intake does give a bump of about 2-3 mpg over the stock intake (on my wife's 328i) More efficient SHOULD give at least a bump in performance too (1-2 hp)

Or, cut out the charcoal filter in the US airbox and get the same thing (cost: $0.00).

Honestly I really doubt that anyway. Are you sure you're not quoting UK mpg vs US? Because UK imperial gallons are larger...

[david in germany]

Originally Posted by rjahl

Think about what you are saying.

A different air box and filter will improve overall engine efficiency by 10%

This is an engine with variable valve timing, variable valve lift, variable intake and a really sophisticated engine management system.

Pumping losses are already very low, the only way you see this kind of change is going from a really dirty filter to a clean one.

BMW did and could not leave that much on the table.

Clean filter to clean filter

[david in germany]

Originally Posted by hassmaschine

Or, cut out the charcoal filter in the US airbox and get the same thing (cost: $0.00).

Honestly I really doubt that anyway. Are you sure you're not quoting UK mpg vs US? Because UK imperial gallons are larger...

Us mpg. I hate hacking parts so I would never cut the charcoal filter. (Original filter box is wrapped up and stowed in my garage) You can doubt if you want but I aim mituculus with fill ups on my cars, I can tell when I get bad gas or when the local stations start serving the winter fuel mixes because of the change of efficiency as well as how the time of day will increase or decrease my usage (traffic or tempature).