After doing the doors I still had two sheets of 4mm bitumen and one sheet of 2mm bitumen left and majority of the 1x2m cotton mat was unused, so I decided to continue soundproofing the car from the rear. Seeing many cheaper japanese cars trunks and rear wheel arches I knew that adding soundproofing there will greatly reduce road noise and also create a better surrounding for a subwoofer in the future.
So I started with removing the rear trim.
1. Remove the wheel repair kit (right) and the jack (left).
2. Remove the top (window) shelf.
3. Push the rear seats forward and remove the trim between the seats and the trunk (attached by velcro on the seats and with clips on the trunk side).
4. Use a 10mm wrench to unscrew the bolts two bolts that are revealed next to the hinges of the trunk floor lid.
5. Lift up the trunk floor lid and you will see two caps in each corner of the floor. Remove these with a screwdriver and unscrew the 10mm bolts revealed.
6. Carefully pull off the rear plastic panel around the trunk lock hook, then pulling upwards remove the rear panel.
7. On the right side inside the tyre repair kit pocket you will see two clips. Push these and pull out the pocket which is to the left of them.
8. Right next to the rear doors, on the floor where the seatbelt goes are small panels covering them. Remove them on both sides.
9. Also remove the rear kickplates (the doorsill part).
10. Grab hold of one of the side panels (doesn't matter which one you choose
first), preferably from the rear (the tyre repair or jack pockets are good places to pull from) and carefully pull. There are four poppers holding the panels (three from the top and one right next to the seatbelt hook on the floor). Also be aware that once you get the poppers released you will need to undo the light cable on the right side and the 12V socket cable on the left side. It will seem as though it is stuck but this is merely because the hooks which hold the rear seat in upright position don't want to go through the trim too easily, so you will probably have to give it a little yank.
11. Remove the floor mat.
This is what is revealed:
As you can see, Honda have added a little soundpoofing here, but its not quite adequate still.
As I was unsure of how close the trim and metal were at some places I took great care in selecting the places where I added thicker bitumen and where I had to limit myself to thinner one. Obviously, having the whole area covered will have slightly greater effects but like I said earlier: its not matter of quantity but its a matter of where you add the proofing. So firstly it would make sense to make sure the wheel arches are covered, then move on to other areas. I also added some around the damper mountings as this reduced the sounds that come from rough roads and of course on the floor of the trunk as this space made a horrible noise when knocked on.
After I was done, this is what it looked like.
Job wasn't too well done on my behalf, as I was kind of in a hurry, so I didn't have too much time to bother with measuring and cutting the pieces exact, but they all got attached tight and more or less in the right places.
Likewise here as with the doors, I added extra cotton (somebody please correct me on this, its not exactly cotton, is it?) to the insides of the trim panels. Here's what they looked like before and after:
Once I was done with that you had to reattach all the removed trim in reverse order, making sure all the poppers were in place and wires attached.
Now the car sounds a lot quieter in the back, there is much less road noise there and also I don't hear the rear dampers as often as I did before. But then again, there is still some road noise coming in from the front wheel arches and at high speeds the roof acts like a diffuser to magnify the wind noise, so in the near future I will need to do something about these problems.
So far alltogether I have used 1 square metre of 4mm and 1square metre of 2mm bitumen totalling about 10kg plus 2square metres of cotton, another kilo of weight.
Total spent is just under £40, but I have no clue of what these materials might cost elsewhere.
To do the four doors took about 4 hours, the trunk took about 2,5 hours.
So overall this all is relatively cheap and not much hassle, but the effects are definitely worth it!
To be continued...