Under hood sound insulation
I really like my Sdrive X1 but found the engine to be a little noisy and not in a good way. After verifying that the underside of the hood is set up for insulation I was very disappointed to find out that none is available for the X1.
After looking around I decided to see if i could make the insulation for the 128 work. The back fit in the slot well but the holes and tabs did not line up properly so I drilled some holes in the hood sub-structure (carefully) to accept the plastic rivets that are used to mount the insulation.
I drilled additional holes (and bought additional rivets) to secure the tabs. Have to be careful that it is centered properly so it does not interfere with the seal line on each edge of the engine compartment (see additional rivet and seal line identified with arrow below).
In the end it reduced the noise by ~1/2 (down 10 db) but the best part is it attenuates the higher frequencies more so the remaining sound does not sound so tinny. You can still clearly hear the engine, especially when it is working hard, but it is quieter and sounds much better.
I am happy with the results (see photos below).