Sound deadening and heat insulation (Mk1)

[cartertronic]

Hey All,

After getting a 2inch exhaust system and having no AC I decided something had to be done about the noise and heat in a Mk1 cabin. I'm currently getting a ABF 16v engine with full Mk3 AC system boxed up and sent to Oz, so before it arrives I've been pursuing a heat and sound insulation project.

Materials
-15 meters of 1200mm wide Double sided sisation foil - reflective heat insulation commonly used in construction ($1.60 per meter - from Motawizza - 9388 0094)
-3 meters of 7mm x 1220mm Crosstep Fire Retardant Foam Insulation ($14.25 p/m at Clark Rubber)
-20 sheets of 'Heavy Duty Sound Barrier Damping Material' ($7.75 per sheet at JayCar - quantities bigger than 2-3 sheers must be ordered in)
I know it seems like a lot of materials, but for $230 you can sound and heat insulate the whole of your floor pan.

The Theory
The insulation I have chosen to install is a combination of different materials; reflective sisation foil and foam for heat insulation, and vinyl/barium sheets for sound deadening.
The sisation foil and foam sandwich mimics other heat insulation products such as Low-E Insulation which can be purchased for $130US (+$80US postage) and would probably be less work to install, but won't have the same sound deadening properties as the barium sheeting... (for a 'how to' on installing the Low-E Insulation check out this Citroen insulation thread)

I should add that the barium sheeting is quite heavy. At 1kg per sheet, you are adding another 20kgs to your car. By the time you add the foam and foil your looking at an added weight of approx 22-24kg.

My theory was to make a sandwich of these 3 materials, using sisation foil to reflect heat, foam to further hinder heat and sound transfer, barium sheeting to block noise (the energy from which transferred into heat - although in very low quantities), and another layer of sisation foil to hold heat in the insulation sandwich and reflect heat from the other side.

Method
-First thing you have to do is pull up all your carpets, check for rust and water leaks... I know a lot of you would rather not know what is happening below the carpets, but its definitely worth it in the long run. I ended up taking the front quarter panels off, welding up holes in the wheel arches, taking the arches, firewall (where needed) and floor pan back to bare metal and preparing it and spraying it.
After a lot of hard work and determination I know have a water proof golf (i know insane isn't it!) with no rust in the floor pan and fire wall. The piece of mind is definitely worth it!

THE BACK: Now its time to get stuck into the insulating! I started in the back because it was a nice flat surface to start with.
Cut off some big sheets of sisation foil (SF) and start tracing patterns of your floor pan, marking out where the seat belts and seat attachment points need to have holes. Using the traced patterns, cut out foam, sound deadening (SD) and SF pieces to match - I cut out 2 new pieces of SF as well as my patterns got a bit tatty. You need 2 layers of SF (top and bottom layers) and 1 piece of foam and SD (middle layers) which you make into a sandwich that goes:
Top layer - SF
Middle layer - Foam
Middle layer - SD
Bottom layer - SF
NOTE: I used the bear minimum of foam so be careful when cutting patterns out! Take your time and try and get as much out of your foam pieces as possible
-Once you have all your patterns cut out spray contact adhesive onto each touching surface of the sandwich (NOTE: Don't spray where the outer layers will touch your car or carpets etc!) and then stick them together. Once they are stuck go and cut out all the seat belt and seat attachment points.
What you are left with is a nice flat insulated surface that can be slipped under the back 'carpet' and can be easily removed if you wanna shed some weight

THE FRONT: The method for the front section of the car is a bit different; you still need to work with big panels of SF, foam and SD, but I choose not to spray contact adhesive in between layers as the insulation will not be disturbed once the carpet is back down.
-There are two ways to lay the SF;
a) Cut off another big piece of SF and start making patterns for all the big flat sections in the floor pan. Remember to cut other pieces of foil covering the exhaust tunnel, front seat support etc. and to make holes for the shifter, hand brake etc.. Join all these bits with electrical tape to avoid hot air running through the seams.
b) Cut out a massive piece of SF and lay it over the floor pan, push it down and scrunch it around each of the lumps (exhaust tunnel, seat support etc).
I chose the first method, but if you're feeling lazy go for it
-Cut out foam and SD pieces and cover the whole floor pan.
-Repeat the SF step and lay another layer of SF. Remember to seal up all seams with tape to stop hot/cold air moving freely.
-Underlay and carpets back down! (can take a little convincing to get them back in place)
-Sit back, crack a(nother) beer and admire your handy work!

PICS - unfortunately my phone died half way through so am missing lots of early photos

First Layer


Foam Up Fire Wall


Foam Across Floor Pan


Remember to leave a space for the seats to drop in! (Note: After this I had to go back and cut away an inch along the rail to avoid the seat legs bottoming out)

[cartertronic]

Sound Deadening


Final Layer


Foam Underlay Down


Carpets Down


There are no pics of the back (as this was done before phone shat itself), but it was the same theory just done in flat panels.

BITS TO LOOK OUT FOR
Make sure there is enough room under/around the pedals (clutch was only one that needed underlay and insulation cut back), seat rails (cut back an inch so the seat legs don't bottom out) and seat sub frame (make sure pin can slide in and out without fouling carpets - otherwise seat adjustments will be a right b@$tard!).
Also, when you put the underlay back you're probably going to have to cut out a square for the heater box (as it won't go behind it now with the other insulation) and trim the ends that hit the seat subframe (as the insulation will push it back a couple of centimeters.

The Results
I should have tested for sound and heat transfer before I started this project (like in the above Citroen thread), but didn't have the resources. However, the theory and materials used are equal to, if not better (added sound deadening) to the Citroen thread, the only thing is he covered his whole car (although tested for heat through the floor pan)!

Either way, I can definitely say that both heat and sound have been significantly reduced.
I took it for a long drive the other night and at all rpm levels the sound has dropped dramatically! Driving down the freeway was so quite it was almost disconcerting
Added to this the heat coming off the exhaust tunnel is now non-existent
I'm hoping for a really scorching day so I can test the heat sink through the floor pan and firewall. Based on the results so far, I'm predicting a big difference.

EDIT: I should add that after finishing one layer of sound deadening I had a few sheets left over which I used to create a double layer in the boot (where I see a lot of exhaust noise happening).

[AusScare]

Brilliant job, definitely on the to do list for anyone using their mk1/2 as a comfortable daily.

Just by the looks of things the rewards could be nothing but massive.

Nice work.

[Golf Houso]

this is definately something mk3 owners should consider as having taken out my interior and doing some dynamatting, you can really see the complete lack of soundproofing in the model...

[mikinoz]

I like this a lot. The quietening down would be great.

The issue I have is that there is no way my car would be watertight enough to get away with this currently...

[Jarred]

How much do you reckon all this insulation wieghed Simon?

Great write up by the way!

[GoLfMan]

Stickied for you mate.

Great write up, would like to do this to my mk1 someday

[cartertronic]

Thanks guys!

Stickied for you mate.

Great write up, would like to do this to my mk1 someday

Cheers! I've learned a lot from this forum, its good to be able contribute in some way!

How much do you reckon all this insulation wieghed Simon?

Great write up by the way!

The sound deadening (vinyl barium sheeting) weighs about 1kg per rectangular sheet (700 x 330) of which I used 20 = 20kgs
The foam weighed next to nothing, so maybe a kg all up max = 1kg
All up the sisation foil was probably a little bit heavier than the foam, but can't have been by much = 2-3kgs

If it was over 25kgs I'd be really surprised..

[Hooligan]

Have you tried the dynamat insulation ?
I have used this stuff in a Hotrod I was restoring