Carbon intake valve cleaning for the 2.0T FSI and 4.2 FSI V8 RS4
Why do my intake valves need carbon cleaning?
In the above pictures you can see the carbon build up on the intake valves and intake port of a Seat Leon Cupra 2.0 TFSI 240 Stage 2 + with 72,000 miles. This carbon build up is up to 2mm thick in places and is a common problem for modern direct injection engines and stems from the crank case ventilation system redirecting oil vapours through the inlet manifold to be burnt up. Previous engines with port or inlet injection (such as the 1.8T 20V) did not suffer with this problem as fuel was mixed with the air prior to flowing over the intake valves and therefore the fuel washed any carbon deposits away. As ever, vehicle manufacturers are trying to increase efficeincy and are choosing direct injection (where fuel is injected directly into the combustion chamber) over port injection for their engines. All of the Volkswagen / Audi / Seat / Skoda FSI or TSI engines are direct injection and suffer from carbon build up. In the picture below you can also see how direct injection works and the fuel spray from the injector completely misses the intake valve.
How are the valves and ports cleaned?
The process of cleaning the ports and valves is fairly straight forward, yet great care needs to be taken not to cause any further damage to the head of the engine or the valves themselves. The valves and ports are cleaned with various chemicals and then media blasted. We require the car for 1 full day to strip down the intake and clean the valves and ports on a 2.0 TFSI engine. All gaskets are also replaced as they are single use only.
How do I know if my valves need cleaning and what difference will it make?
Carbon build up is a natural occurance on direct injection engines and there is pretty much no way of stopping it. Sophisticated catch cans and alternative oils are said to help prevent the build up but will not stop it completely. Generally speaking an engine with only 20,000 miles on the clock will have a sufficient build up of carbon, so we recommend having your intake valves checked at these intervals. Constant misfires, lack of responsiveness and poor fuel economy can also be related and cured by having this service carried out. If you leave the carbon to build up then these problems can only worsen and possibly cause major damage if a sizable carbon pellet falls into the cylinder.
Once the service is complete your engine will feel more responsive, smoother and more powerful. A cleaner intake port will reduce turbulent air flow and therefore your engine can make more power with less effort. It is ideal to combine carbon cleaning with a More-BHP remap to further increase results. On the dyno graph below you can see the improvements in engine performance:
Even though, peak power is exactly the same, there are surprisingly large increases in torque between 1,500 and 5,000 RPM. Peak torque has increased by 31NM and there are increases of up to 40NM at 2,500 RPM. The increases can also be felt on the road as the car pulls a lot harder before the main turbo surge and is less jerky to drive at very low speeds around town. Remember, this is a car with 72,000 miles on the clock, if your car has done a higher mileage and has never had the valves cleaned before, you may see bigger increases than this.
Audi 4.2 FSI V8 RS4 carbon valve cleaning
One of the most affected engines is the 4.2 FSI V8 found in the Audi RS4. Reports have circulated that owners have been loosing up to 30BHP alone just from a build up of carbon on the intake valves and ports! For a dedicated performance vehicle this is a serious problem that Audi are failing to address. We have now completed a full carbon clean of the intake valves on our very own Audi RS4 B7 4.2FSI V8.
Here are some pictures of the cleaning process: