I’ve previously added Dynamat sound-deadening to the doors in an attempt to reduce road noise, especially that coming from the rear. While the improvement in audio quality was noticeable, it only had a limited effect on the noise level in the cabin. I saw online that several people had added sound-deadening to the rear wheel wells with good results, so this is something that I wanted to try. I first tried getting access from the inside the cabin, but this proved to be next to impossible. So the approach that I took (and that others have taken too, even on 991s) is to stick the Dynamat onto the wheel side of the well, behind the lining where it is protected.
In order to get access the wheels need to be removed. The well liner is held in place with two T25 screws and three 10mm plastic nuts. There was lots of dirt stuck onto the metal that I first had to clean off with water, sponge and paper towels.
I then cut the Dynamat to size. I did not bother with making a cardboard template first as this area is easy to access. I ended up with three pieces in total, two for the outer panel, one for the inner panel. I did not cut holes for the plastic grommets as these are leftovers from the manufacturing/painting process and should not require removal. Here’s the result on the left side before covering it up with the liner. As mentioned before there’s no necessity for 100% coverage as the goal here is not sound insulation, but changing the resonance frequency to reduce sound transfer and amplification.
I haven’t driven on my reference track yet for a noise level measurement, but during a test drive I had the impression that the road noise was less noticeable and that the engine noise now was in the foreground – which is the result I was aiming for.
