Swirl flaps are small butterfly valves fitted to the intake manifold just before the cylinder head intake ports of most modern diesel engines.
But what do Swirl Flaps actually do?
Their purpose is to ensure that the air entering the cylinder is sufficiently turbulent for good fuel-air mixing even at low engine speeds. This aids in reducing certain toxic emissions and may also improve low-end power and torque.
How do the Swirl Flaps Work?
The position of the swirl flaps is adjusted by an electrical or vacuum-activated servo-mechanism which is under the control of the engine management system. Typically the swirl flaps will be closed at idle speed, creating additional turbulence in the intake. As engine speed increases, the swirl flaps are gradually opened until, at around 2,000 RPM, they are parallel to the airflow and present virtually no resistance.
That sounds good, but why do Swirl Flaps create issues for most cars?
Swirl Flaps present two main problems both of which can be a nuisance or even a very hefty repair bill!
- A common issue with the swirl flaps is fouling by the exhaust gases which leaves tar-like deposits on the swirl flaps in the inside of the intake manifold. As time goes on the swirl flaps may begin to stick in one position and the EMG may report an error code in the correct swirl flap position is not achieved even to within a few percent!
- A more serious issue caused by the swirl flaps, or their mountings, is if they fracture. Given the very nature and design of the swirl flaps, should they fracture or crack then any fragments of metal will instantly be sucked into the engine and because of the small clearances inside a diesel engine this will almost always cause major engine damage and end up costing thousands!
I don't want a repair bill of thousands! What do I do about my Swirl Flaps?
That's where we come in. at MBM Autohaus we have years of experience in dealing with engines and because of our extensive experience we have been able to come up with a solution and the solution is known as a "blanking plate".
What we would recommend is that cars with Swirl Flap issues, or any owner who has had a bad experience with Swirl Flaps, brings their car to us and we will remove all of the swirl flaps for you. Many people will leave it there but this causes a substantial drop in air pressure which will affect the performance of your vehicle.
So we go a step further and once we have removed the swirl flaps we will then replace them with tailor-made aluminium blanking plates which will allow the intake manifold to keep the air pressure high enough to not affect performance.
But what are the downsides of having Blanking Plates instead of Swirl Flaps?
There are so few downsides which is why we recommend them but there are two factors which you should consider before replacing your Swirl Flaps.
- Firstly, you may notice a very slight drop in car performance at low revs (particularly before 2,000RPM)
- Secondly, the emissions from your car will raise slightly.
However, both of these changes are so negligible that you will barely notice any difference and most people have reported no difference at all.
So if you're looking to have your Swirl Flaps replaced then give us a call today on 0121 356 9633 and quote "Swirl Flaps".