Hi guys, i wanted to open a dedicated topic for Swirl Flaps function. I saw a lot of posts with pro and cons of flaps and a lot of bad information and misunderstanding.
We know that on BMW mostly, these flaps can create engine damages by falling into engine. Many people claims power loss on light driving in low rpm range. Also we know that on low-rpm area, they close an inlet port of air for every cylinder, well air will go only through one port, maybe with little high velocity. But how important is velocity in a direct injected diesel engine ? There is already turbulence on a presurized intake on a turbo diesel, i'm wondering what real effect can have that little additional amount of turbulence/air speed.

What's the real gain of flaps ? My opinion is that they were implemented for EGR, to avoid EGR side effects(carbon deposits and low oxygen mass), and use that less air available as optim as possible.
What are your thoughts ? Is there any real reason to keep a healthy pair of flaps ON after remap and EGR off ?

Maybe some real tests on dyno on part-load ?

I think SWIRL effect is depend from engine. On my 2.2dci 710 with flaps constantly closed by direct connected control pipe to vacuum I see positive result at rpm below 2000. Engine run more soft, more torque near to idle, less fuel consumption at low rpm. But after 2000 rpm engine lose power and fuel consumption rise. I think for my engine optimal is closed flaps below 1500-1600 rpm and open when more.

Do you have EGR still active ? Even under 2000 rpm with EGR off there should be a lot of air and have AFR very high, excess of oxygen

EGR always closed by plate and switch in fw. I understund you sceptic but I drive with closed flaps few handred km and have experience. With open flaps rising after 2000 is mach better. I dont know why boost not compensate one closed inlet port after 2000 rpm, but my practic show this. With closed flaps air go to cylinder with big turbulency and more good mix with injected fuel. This give more fast and full combustian. Max pressure point shift to more early. Possible this more optimal at low rpm and nonoptimal after 2000 rpm.

Nice information, it makes sense theorethically, in low rpm area turbo pushes very little air , but what about stock cars when EGR is active ? This air is half and this thing makes things worse.
I blocked my flaps, now i have oxygen excess but i enrich my smoke map and made pedal more senstive, i can't feel any lag now and also i added 3 degrees to EGR zone timing