Swirlflaps / vertebral valves

Swirl flaps or vertebral valves are small butterfly valves in the inlet manifold just before the inlet openings of the cylinder head of many modern diesel engines and fuel engines including those of Alfa Romeo, Audi, BMW, Mercedes and Opel.

The valves are smaller than the inlet channels and therefore let air pass around them, even when they are “closed”. The valves themselves are made of stainless steel or plastic and are attached to a rod with two small Torx screws.

Due to contamination due to exhaust gas recirculation, there is a tar -like soot on the valves and the inside of the inlet manifold. Over time, the valves can start to stick in a position and the engine management system can give an error code if the correct flap/valve position is not within a few percent of the
given posistie can be reached. This can cause problems with engine power, stuttering or worse fuel consumption.

With some models, including various BMW models, the valve can break under voltage and parts then end up in the cylinder. This almost always causes large engine damage as a result of the loosened part, which is then beaten back and forth in the cylinder with X 1000 revolutions per minute with all its consequences.

A solution is preventively to replace the inlet manifold to stay this potential danger or remove it with a special Swirlflap Delete Kit to close the open holes in the manifold that occurs after removing the valves.

After placing this Swirl Kit, the software of the car must be adjusted to prevent malfunctions.