This Audi S5 was in our workshop last week for a common issue .

Carbon removal on all FSI and TFSI is a subject which needs little or no introduction, due to TFSI/FSI engine design aimed at lowering harmful emissions and increasing power and torque the injector no longer sits in the manifold which provides no cleaning properties to the inlet valves.

The injectors are now located directly in the combustion chamber and aimed directly at the crowned piston creating a unique injector spray pattern and flame spread within the cylinder, a bi product of which is heavy carbon build up on and around the inlet valves which ultimately causes loss of power from the engine by reducing the capacity to burn fuel and air !

Other symptoms include poor performance, miss fire, lumpy idle speed, lethargic engine response, poor fuel consumption, engine MIL lamp, restricted performance and generally just really bad for the breath-ability of your engine and needs getting rid of fast !!

CAT have tried and tested many methods of cleaning the carbon from the inlet valves and have found by far the best way is to use polymer beads which are blasted in at high velocity, this method is both incredibly clean and efficient.

 

20180307_112553   Inlet manifold removed

 

20180307_113002 Carbon build up before cleaning

20180307_112801 Carbon build up before cleaning

20180307_154823 After cleaning valves

20180307_154801 After cleaning valves

This is the owners verdict of how the car ran after the work was carried out :-

Hi Clive,

Many thanks for the photos.

Having had a couple of days to drive the car since the inlet clean it is quite striking to see the different it has made.

Before we had noticed it seemed a bit down on power especially at lower revs. Also it would typically run rough and stutter on acceleration on cold starts for the first minute or two.

Cold start now is far more smooth both at idle and when first pulling away.

Most dramatic is power delivery that is now appears restored in the lower rev band and pulls nicely from around 2000rpm upwards where before it seems like it was choked back until passed over 3000rpm.