Air Box Restriction?

[trickett_james]

Mines mapped and got a de cat so I'll get one ordered. Cheers

[mit]

Would I see any benefits from a k&n then? Thought I'd read on here that I'm best with a standard filter and I've just put a new one in

On a standard car, no. On a remapped car, yes. I had one in my last 330d and will be fitting one in this 330d when I start tuning it.

Mines mapped and got a de cat so I'll get one ordered. Cheers

No, you misunderstood him.

You won't see any benefit from a K&N filter.

If you already have a remap, you still won't see any benefit.

If you have a K&N filter and have a custom map done taking the new filter into account, you will see a small benefit, but not much.

Also with a K&N filter you have to be very careful with oiling it, as even slightly too much oil will deposit itself all over your MAF sensor, negating any performance benefit and costing you about £160 for a new one.

[Blair]

Before you do anything you need to see what map sensor is reading at WOT this will determine if you have a restrictive intake or not.

[Ginger]

Hi guys, new to this site, but i've been fixing BMWs for years.

Fitting any high flow airfilters on the m57or tu engines don't do anything worth mentioning. Diesels will run fueling, in response the what info is given to the DDE by the airflow meter. Airflow meters are designed to read what a matched standard airfilter gives. Putting a high flow filter can actually cause the meter to back off fueling to compensate the excessive flow.

Best bet is to fit a new filter, new crankcase breather filter to reduce oil saturation in the intake system, and a quality remap by the likes of CA or Evolve.

The next step would be to fit a better IC (intercooler) from a reputable tuning company.

After the above, i don't see the point of chasing anymore power from these engines. As they do have a tendancy to throw timing chains when pushed for a long time.