Rear Vanagon Body Air Intake Sound deadening ?

[metropoj]

So, my TiiCo is loud, as expected, after all the readings. I have gutted the rear cabinets out, removed the water soaked foam above the tranny on the outside and have the perfect breeding ground for noise and vibration !

I read through Dylan's threads where he sprays Lizard Skin. Thanks for putting the time in to show us, sir !

I have found a company called "Second Skin" north of the border here that provides a layered approach of Dampeners, Noise Barriers and a coating similar to Lizard Skin.

http://www.wheelclass.ca/secondskin.html

My question is what to do with the rather large resonating chambers in the rear pillars where intake manifolds go. I hope I didn't miss this in the write-ups thus far ....

It would appear a bad idea to use a dampening mat inside the pillars from the outside that will capture moisture. it would appear that a product like Second Skin Sludge, Al's Liner or Lizard Skin would be OK to spray or roll on where the intake snorkel chamber resides ? I don't want something absorbing moisture.

My only other option is a rather thin layer of sound deadening from the inside that gets covered by my trim work.

Thoughts ? Right now function is over weighing cost considerations so I really want the best deadening option for my girls.

I'd rather they lose their hearing gradually listening to Rock over Inline 4 exhaust noise lol ....
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John.
86 TiiCo powered Westy.

[Merian]

not clear what noise you are trying to abate - is it induction howl?

deadening usually means dampening a panel that is vibrating - that lowers the freq. and reduces the amplitude

there are ways to reduce noise resulting from flow thru a tube which is essentially what the rear pillar enclosure is - but it isn't a problem on stock Vans - did you change something there?

[Jeffrey Lee]

Couldn't find a functioning link but Sambanista "Gnarlodious" "... forced a tube of Rubatex inside (the air intake tube), a type of stiff foam mat that expanded to fit tightly. The results have been great, and intake noise is at a minimum."

BTW, here's a link to that convo: http://www.thesamba.com/vw/forum/viewtopic.php?t=6...highlight=

[metropoj]

[Christopher Schimke]

Given the areas that you talked about, if I were in your shoes would place a blanket of this on top of the entire rear deck and down the firewall inside the cabin.

http://cascadeaudio.com/car_noise_control/vb_tsm.htm

For the intake plenums, I would cover them on the interior of the van with this.

http://cascadeaudio.com/car_noise_control/vb_4.htm

or this

http://cascadeaudio.com/car_noise_control/vb_45.html

I have used the VB4 and it's a great product. You can buy mass loaded vinyl and thin closed cell foam separately for cheaper than you can buy the pre-made product, but you need to use a special vinyl glue to adhere the vinyl to the foam.

Don't forget that part of the plenum runs inside the sidewall cavities, so you will want to cover those areas too.
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[metropoj]

Hey that's cool stuff, thanks for sharing those links. I guess in reality the rear of a Vanagon is nothing more than a large rear power generator box !

I managed to also save an OEM diesel Transporter foam/rubber cargo pad for the back area as well but it is a little tattered. I'd like some newer tech back there since 82.

Almost 6 square ft from rear hatch to floor behind seat, plus the insulated areas.

I also found that my rear washer bottle has a bit of a leak since my insulation had some blue staining on it. Seams etc still look good in the walls and will receive another coating

I'm yanking the insulation and go with Roxul or something else suggested from the many suggestions from the board.
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John.
86 TiiCo powered Westy.

[AndyBees]

Sharing a bit of sound reduction endeavor in my Tin-top Vanagon after the TDI install.

I used a combo/variety of things, such as dynamat, imitation dynamat, and covered with an aluminum covered bubble wrap (very small bubbles) designed for noise reduction.

The area around the custom deck lid also was covered with the aluminum covered bubble warp (dynamat can be seen). The lid has a combo of layered sound reduction material on the under side.

I too would like to address the Body Air Intake areas ... just not got around to it yet.

Here is one photo:

Edit: The pic below shows the two layers and gives a view of the aluminum coated sound deadening material.

More photos here: http://pics.tdiclub.com/showgallery.php?cat=5985
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[metropoj]

One thing always on my mind is if after I spend what seems to be a lot of money, if it will make me happy with the sound deadening properties... Covering like you did right to the body I think is key.

Another thing I read up that may also cause my issues is the actual install itself.

Jon for FAS mentioned the importance of making sure that the Inline 4 hangs properly without any stress on any of the mounts etc and not 'forced' into place and torqued into place that way.

Since I have all new mounts from tranny back, I think it is time for me to rehang the engine and ensure I didn't force things into place and creating my own hell.

I also want to make sure the welds on one of my carrier bars to the body are nice and solid.

Finally, the worse case scenario, is a poorly built lower end right from the factory causing my body noise

I have a spare TiiCo block I am thinking of sending out to a shop to properly blueprint and balance the whole lower end.

I was just so excited to get a brand new motor in my van I didn't bother to check for such a thing....
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John.
86 TiiCo powered Westy.

[AndyBees]

Yes, I agree with respect to the motor mounts. It is important that they not be too solid, otherwise, they will transmit vibes throughout the body.

My motor mounts are too stiff. I plan to make considerable modifications with them. I'm in the planning stages of doing another TDI install in a recently purchased 89 weekender. So, the motor mounts are going to receive lots of attention.

I'm not sure about the gasser engine, but the diesel engine "intake system" from the filter to the engine head needs some "dead-in" curves to reflect valve opening sound coming out of the cylinder head. That's something I need to address as well.

My engine noise is okay up to about 68 mph (engine at 3000 rpms). From that point on, the noise increases considerably as the speed increases.
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[metropoj]

I am in 100% the same boat as you. I got rid of a nasty vibration at 2800 ( ended up being my licence plate ! ) but it just escalates from there in noise in the same range. I figured I wasn't alone.

Funny you mentioned the intake. Yes, I hear that same valve train noise at idle and upwards too on my gasser. I only have one 90 degree bend from the intake manifold through the airbox and a 90 up to the snorkel.

There was a guy selling adapters to put in the Audi mounts into the Diesel bars that i don't see anymore, but alas, I am getting off topic on my own posting ....
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John.
86 TiiCo powered Westy.