Meet the C6

Every time I saw a C6 on the road I would say “That will be my next car”. It's exclusive and different from everything else on the road, the design looks timeless and it's a car that was made for silence and comfort. Citroën uses the legendary hydropneumatic suspension that filters road imperfections and give you that “magic carpet ride” feeling.

So, less vibrations, less rattles. But Citroën took special care and added laminated side windows and deadening materials to keep the air borne noise low.

With a lot of equipment that I deemed necessary, like electric seats with memory, dimming rear view mirrors and leather everywhere this was the perfect car for me. Also had some nice features like the HUD that shows the car speed and other information on the front window and the AFIL that vibrates your bottom when you go over a white line on the road without using your indicators.

The only problem is that Portugal is going thru a diesel fever so I couldn't find any C6 with a petrol engine. A petrol engine is quieter, has a decent engine sound, cheaper to maintain and if converted to LPG much cheaper to run.

But I really wanted a C6 so I went for the V6 model with an automatic transmission. More power, more torque, less noise. I found a nice 2.7 HDi Exclusive in Bleu Mauritius with the Wadibis interior, traded the 406 Coupé and got myself a new car.

The timeless C6
The timeless C6
Wadibis interior on the C6
Wadibis interior on the C6

Sound deadening

The car is quite silent as it comes from factory, but not as silent as the 406. The idea was to keep it without any deadening, but the engine noise of a tractor, as all diesel engines sound, was getting on my nerves, so I added Dynamat to the bonnet.

But the drivers side door limiter needed to be replaced, and the door card had to come off, so why not add some Dynamat to the door?

But why add more deadening on a C6, isn't it overkill? Yes, it is, but the 406 was ever so slightly more silent. Driving on the highway I wouldn't hear the other cars rolling noise, on the C6 there was a very muffled sound when a car would pass me by. If I had never driven a deadened car this would be quite amazing, but with the experience on the 406 I knew it could be even better. I could also be listening to music on the 406 without too much noise coming out of the car, on the C6 not so much.

The C6 also has a problem, too much glass. In the portuguese summer the car is like a greenhouse on wheels and the air-con has to work harder, meaning more noise from the air-con fans and more fuel usage. If I use Dynamat Extreme and Dynaliner I will be able to reduce the ambient temperature in the car.

Measuring the results

The 406 was the car were I tried different materials and techniques. Now that I have some know-how I will try to measure the results of the sound deadening steps. It will be hard, I will use my mobile phone with an application to measure noise levels. It's not properly calibrated but will be enough to measure differences before and after deadening.

Measuring the sound level is not very scientific, the overall sound level can be the same but some frequencies can enhance our perception of noise. You can have a 40dB engine rumble and it will not sound as noisy as a gush of wind that produces the same 40dB.

I will also try to account for the weight that is added to the car. For future reference one sheet of Dynamat Extreme (a bulk pack has 9) weighs 900 grams.

Citroën C6
Done in 02 of June, 2013