22 mm and 33 mm Swirl Flap Flaps Delete Removal Blanks Plugs For BMW M57 M57N M57TU
 
The material of the end caps is the same as of the intake manifold, additionally reinforced with glass fiber
Lack of differences in the thermal expansion between the manifold and the caps
Professional quality of manufacturing
To remove the swirl flaps you will need one piece per cylinder, so 6 per engine.
 
There are two types of sizes:
 
smaller swirl flaps (22 mm), designed for vehicles manufactured up to 2004;
larger swirl flaps (33 mm), designed for vehicles manufactured since 2004;
you need to measure the hole in the manifold for engines made in 2004. In 2004 were used two sizes of swirl flaps.