What are swirl flaps?
Swirl flaps are butterfly valves, located in the Inlet manifold of most modern diesels. At low engine speeds they are actuated to help improve air fuel ratios and improve emmisions, when closed they cause the air to swirl into the combustions chambers, which helps to create a leaner mixture and aids combustion. Beyond around 2000rpm they are opened and have minimal effect on driving.
What is the problem? and how do we fix it?
The Swirl flaps design is the major flaw and what leads to issues, over time the flaps themselves become brittle and can break away. They also use small screws In the construction which can become loose. Due to the position of the valves in the intake manifold, any part of the valve coming loose will mean it enters the combustion chamber and can cause catastrophic damage to valves, pistons, Injectors, cylinder head etc.
These issues are most notably seen in early BMW engines, they improved the design in around 2004-2005 but the new valves still had the same issues. Even before a major failure, the valves if not working 100% will cause poor running and poor economy, they are also prone to blocking up with carbon which which causes loss of performance.
The Usual process for removing the valves is to remove the intake manifold, strip the valve assembly, and fit custom made blanking plates to seal the opening left in the intake manifold. If the valves are electronically actuated then you will also be required to remap the ECU to turn off the actuator and avoid any fault lights appearing. We would recommend having the vehicle remapped with any swirl flap removal anyway to help boost performance and Improve driveability.
How much does this cost?
The cost depends on the vehicle, and whether the ecu needs remapping at the same time. We recommend getting in contact with your vehicle details for an accurate quote as we can normally offer a package including other services to make an even bigger difference.