Diesel engine: above transmission acoustic mat replacement

[Gnarlodious]

Dropped the transmission and went crazy tearing out all the sagging stuff, what a dirty job. I measured 34x66 inches to replace it, so I pre-ordered 2 sheets of the Tufcote Noise Barrier/Absorber #104-E from http://www.supremesupplycompany.com/sound.htm Size is 32x36 per mat @ $89 each + UPS totaled $231.88. The mat is 1¼" thick and heavy and not foldable so shipping is premium. This is a sound barrier for diesel engine compartments having a bonded 4 mil aluminized mylar exposed surface that is surprisingly tough. Just the stuff to dampen the engine noise and stand up to pressure washing!

Notice how the mat has a discontinuity layer to interrupt long waves specifically emitted by the diesel engine.

I ordered non-sticky as I figured the geometries in the space were not conducive to adjusting sticky-backed sheets. I used “Permatex® Headliner and Carpet Adhesive" in a spray can where needed, mostly at the corners and edges. The glue melts the foam so use sparingly and let firm up or it makes a gooey mess. Not recommended to pre-spray large pieces before they are positioned as the glue is rather unforgiving once it sticks to anything. If you insist on complete gluing you are better off cutting smaller pieces that fit between the frame members without too much sliding around. The rigid "decoupler layer" is non-compressing and so assists in holding the mat up into the Vanagon's odd angle with a minimum of glue, or no glue at all if using the original spring rods.

Clean and/or degrease surfaces if you want tape and/or glue to stick well. Wear eye protection. Very important to have compressed air to assist in blowing out the dirt.

I cut the mats across the short way, making the lengths 32" long. The photo below shows the seam conveniently falling exactly where the cables pass through the firewall, making installation much easier. This space takes a mat 43¾" by 6¾, so one piece 32" long and one piece 11¾ fits perfectly and makes for easy fitting:

The large black curve is the heater hose insulated by foam tubing. The white cable on the bottom I installed for turbocharger gauges which runs through a hole in the firewall exactly between the mats, and you also see my auxiliary battery cable. This mat pressed into place tightly and stayed without support, although with heat and vibration it may eventually fall down so I taped it. The old mats had a springy rod retaining system that I could reuse, but compressing acoustic foam cancels the effect. I'll keep my eye on it to make sure gravity is not having its way, but the retainers are on hand in case of sagging. If you are wet climate driving or mud bogging I'd recommend sealing it with aluminum all-weather tape, as this foam can get pretty heavy when wet. The main thing for me was to get the mat up there while the transmission was out. I can always waterproof it later.

Put your mat in position and press hard where the seat belt anchors bolt through. I used a side cutter to make a hole slightly larger than the bolt to accommodate the wider sleeve the bolt goes through:

Cut a slot for the mat to clear the frame:

This piece stays in position nicely by being compressed so don’t cut the slot too deeply or you lose support.

I used the "3M® Aluminum Weatherproof Tape" to seal it up:

The cable you see is the diesel speed control and the wire is for the auxiliary battery. When I put the 5-speed in the snout does press significantly on the thicker mat so I expect it to be shredded after a while. Oh well.

I have most of the second sheet leftover, although one sheet is probably not enough for full coverage. I will probably glue it under the engine lid for more noise damping. I like the idea of an oil proof material on the engine cover.

All in all I am expecting a huge acoustical improvement, as well as thermal isolation during extreme temperatures. Will update this after driving a while.
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[AndyBees]

Although I used different materials, the results for my project were amazingly reduced engine sound.

Your sound deadening project is an example of what all who own or do a diesel conversion need to strongly consider. Otherwise, the vibes and associated noise from the diesel engine will be a horrible experience.

Your job looks to be well done with good planning!
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'84 Vanagon Tin-top, ALH TDI, two trips to Alaska, 2014 & 16. 1989 Tin-top unmolested.
1983 Air-cool, 225k miles, 180k miles mine, seven trips to Alaska from 1986 thru 2003. 1975 Bay hopeful.

[IdahoDoug]

Nice job - well done! I once tested two identical small inboard diesel boats we were considering. They were both new, but one had an optional kit on it from a company I think called SoundDown consisting of custom layered stick on insulation. I was so surprised at the difference I questioned the sales rep's description and looked for myself in the engine bays. I just could not accept that both were the same diesel engine! Proper sound absorbing material like yours is expensive, but worth the difference IMO.

DougM
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

[vwwestyman]

Review? How did it work out?
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Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Gnarlodious]

Maybe I am imagining it but it sure sounds like the inside of the van is quieter! But really only when the windows are closed. The real droning is diminished, but I am still hearing the upper wavelengths. Which is fine because this engine purrs like a warm kitty cat.

A shot of what it looks like through the above-wheel (the 3 cables power my block heaters):

I went through cleaning all the surfaces and sealed off the edges with aluminum tape, preventing water from splashing up onto the sponge. Now I can pressure-wash it every spring without worry!

My van is so high-slung that I always see through that hole in the parking lot, and I wondered if others looked through there too. Where before all I saw was grungy shredded flop, now it looks all shiny and space-age!

Extreme Vanagon yum!

BTW, I still have almost a full sheet left, so I will be gluing it under the engine lid.
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[Gnarlodious]

After taking my first long drive of 400 miles I am delighted to report that the Vanagon’s comfort level is vastly improved. I really noticed it on the long drive with closed windows. Much quieter inside, with the thudding diesel noise greatly diminished. I can hear again! Really happy about this modification!
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[ALIKA T3]

Great, I was just thinking about doing something similar, thank you for sharing
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Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget

[Gizmoman]

I replaced the nasty stuff with 2" rigid insulation as I already had it. Then I covered that with sound matt - sort of like tar with an aluminum cover.
The van was much quieter for sure.
The next fix was the intake noise and a custom can and snorkel fixed that for the most part.

Now I just need to replace the tired DK tranny. The extra HP is making it louder every time I drive it.

Congrats on your fix, very well done
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82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[dobryan]

[Waldi]

I have used there "Zellkautschuk" google translator "cellular rubber"

[AndyBees]

[dobryan]

Andy,

Thanks. I am interested in what I can do under the floor pan above the tranny where the old sound deadening material is falling apart.
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Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[vwwestyman]

How thick and sturdy is this aluminum cover? You say you can pressure wash it, I guess it must be fairly sturdy.

I'd be worried about water finding a way in somehow, and encouraging rust against the metal.

In the top of the engine compartment this does sound like a pretty good material.

I think that a thick layer of closed cell foam covered by the tar stuff might be a good option for the panel in front of the transmission, where water ingress is a higher risk.
_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Gnarlodious]

The “aluminum” is actually a thick aluminized mylar, so no metal is exposed to corrosive water spraying up from the road. The taped edges are holding good after a winter of slush and water. I wanted to do the edges with a strong sealer to protect against the blaster wand which could damage exposed foam. No doubt further coating the corners with a rubbery or tarlike coating may be a good idea for wet climates, but I am in the dry country and not worried about it. If you do apply it from a spray can, I may suggest masking off the areas you don’t want covered.
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[vwwestyman]

Andy Bees,

Do you recall the brand name of the aluminum lined foam insulation you used and/or where you bought it?

Thanks!
_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Gnarlodious]

The info is given in the first post.
I have to say that shipping on this stuff is expensive because it is not foldable and has to go in a huge box. Maybe there is a place to buy it or get it locally where shipping is less of an expense. I couldn’t identify the exact part because there is no marks on it.
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[iliketowalk]

Sorry to bump this way from the past - but this is definitely on my list since my van came (to me) with 0 sound barrier in this area.

How's it holding up a few years on?

I noticed you also installed the Donaldson intake (after this), did that have a significant sound impact also? Will probably also need one of these as open cone filter is very loud.

You're an expensive guy to hang around...
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1986 Weekender "Birch"

[Gnarlodious]

This material and the aluminum tape has held up real good. Glad I did it.

I would just suggest cleaning the surface good where the tape has to stick on, possibly roughing it up with a wire brush. I’ve found some areas coming off where I was not thorough with surface prep.

I had a CV boot break apart and sling grease all up onto the mylar. It was easy to clean off with solvent.

I put in a new transmission recently and was pleased that the material slides nicely as the transmission vibrates and shifts. Its a 5-speed so I was worried the longer trans would damage the aluminized mylar. But it looked OK, just a bit compressed there above the nose cone. See my concern in the original post.

The intake is definitely quieter with the filter under there. It was a noisy intake with the stock intake in the snorkel.
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[AndyBees]

Although my filter and intake piping is totally fabricated (not Donaldson), it was fairly quiet, I thought.

So, last June before heading out on a month long trip to Alaska, I added some "piping" to the snorkel of the filter with two 90 degree dead-end turns. I put some foam padding at the dead-ends. The results were less than I had hoped for.

If you take a look at the intake plumbing of big cars/trucks, you will notice there will be at least two dead-end chambers to absorb the noise pulses from the cylinders when the Intake Valves are open! That's what I was trying to do. However, I believe the concept works better if it is set-up pre-filter.

Otherwise, I am pleased with all the other sound deadening I did to my TDI Vanagon. Oh, and I did go back to the OE rubber motor mounts that come with the original diesel engine! That was a big improvement over the hydraulic mounts that I initially used (for a 1989 Saab). They were too stiff!
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'84 Vanagon Tin-top, ALH TDI, two trips to Alaska, 2014 & 16. 1989 Tin-top unmolested.
1983 Air-cool, 225k miles, 180k miles mine, seven trips to Alaska from 1986 thru 2003. 1975 Bay hopeful.

[vwwestyman]

What did you build your intake system out of? I really need to improve mine, I believe it is the biggest source of noise at this time in my '78.

The intercoler is different, but the pre-turbo is more or less the same still as this older photo. Thankfully a lot of the rest of the conversion is improved since this photo, but the intake is the same.

_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing