Err... Yeah. I posted that. I was proving Trackrat is wrong and that there may actually be measureable gains by changing to the less restrictive EU filter. Otherwise it would be cheaper for BMW to have one part. Clearly the EU filter is the higher flow and speced part. The US version is an emissions requirement that is a detriment to flow.
Originally Posted by FStop7
Because of an emissions rule in the US that does not exist in Europe.
2009 Space Gray Carbon Leather E90 with DCT, Tech package, and EPS. Mods: Fabspeed 200 cell cats, Xpipe w/resonators and no secondary cats, BPM tune, Euro DCT software, Eisenmann Sport Mufflers, Vorsteiner Rear Diffuser II, SWS8 subs, JL Audio XD400 bridged 2X200W, built in radar