I finally had enough of the noise in my ’92 Sierra and went about soundproofing.
I was after a better solution than wearing headphones or turning up the radio (which in my case is far too weak anyway!)
Hope this guide helps anyone in a similar situation.
Materials & Cost:
All from Clark Rubber
1 sq m closed cell foam (EVA 75, 6mm) - $80.00
1 sq m Formshield heat resistant foam (10mm) with adhesive backing - $40.00
1 can contact adhesive spray - $15
Clark’s have closed cell foam with lower EVA numbers – cheaper but not as dense and not as good at insulating.
Application:
The main areas I targeted where: firewall (engine bay and inside), floor, wheel arches.
Engine Firewall:
Formshield heat resistant foam used here.
1. Create shapes of sections of the firewall using newspaper.
2. Use the shape as a template to cut out the right shape in the Formshield foam.
3. Clean the section of the firewall with Wax/Grease remover
4. Stick on the section of foam. Keep the size of the shapes small, no bigger than your hand as some of the areas are hard to access, and peeling of the backing paper and sticking it on will be hard.
Inside Firewall
Closed Cell Foam used here
Best to remove the front seats for easiest access. It’s can be a pain in the ass otherwise.
Some approach of using newspaper templates as above, except that you’ll need to use the Contact Adhesive on the firewall and foam and hold it in place for a short while.
My only regret here was that I should have bought better/stronger adhesive.
Floor – incl. under the seats
Close Cell Foam used here.
None of the foam here was glued down as I wanted to be able to easily remove it for cleaning.
Rear wheel arches
Formshield foam was used here.
The Formshield is much better at bending and sticking to curved surfaces.
Same process with newspapers first, just make sure to cut holes around the sections where the wheel arch carpeting locks in.
Verdict:
The level of noise in the cabin has been massively reduced. Probably now best described as a dull roar
This was a reasonably cheap solution, much better than buying specialist soundproofing material like Dynomat.
I’ve been using the car for the last 3 weeks and the heat resistant foam on the firewall has held on nicely and I haven’t had any overheading issues.
Before doing the above soundproofing I also tried applying bitumen paint/paste to the outer wheel wells as in the guide http://www.rs25.com/forums/f105/t76778-diy-wheel-well-sound-deadening.html.
Wasn't very effective at all.