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09 ZD30 CRD Wagon
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Discussion Starter #1
After a deafening highway trip I’ve decided to sound deaden the wagon as much as possible.

I’m going to remove the seats and carpets completely to do the job. While I can get the dynamat (or cheaper alternative) pretty far up the firewall, I’m considering moving the dash to get it right up the top and block some more of that engine noise.

It’s a 2009 ST Wagon with dual airbags. I probably wouldn’t need to remove it completely, just lift it enough to get my hand up there.

Removing a dash completely looks like a huge job.
Worth the effort?
 

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CRD Wagon
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After a deafening highway trip I’ve decided to sound deaden the wagon as much as possible.

I’m going to remove the seats and carpets completely to do the job. While I can get the dynamat (or cheaper alternative) pretty far up the firewall, I’m considering moving the dash to get it right up the top and block some more of that engine noise.

It’s a 2009 ST Wagon with dual airbags. I probably wouldn’t need to remove it completely, just lift it enough to get my hand up there.

Removing a dash completely looks like a huge job.
Worth the effort?
What sort of exhaust have you got? These things are pretty quiet stock IMO.

I dont think dash removal is warranted.

More specifically, I did dynamat once. It was on a Suzuki Sierra. I did as much of the dash as I could without removing, the floor pan, wheelarches. I didnt bother behind the dash or the doors.

It made a huge difference.
 

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09 ZD30 CRD Wagon
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Discussion Starter #3
What sort of exhaust have you got? These things are pretty quiet stock IMO.

I dont think dash removal is warranted.
The stock is. 3” with cat and muffler. The noise is almost entirely from the STUPID stainless steel snorkel. What a waste of money that was.
Also a lot of noise from the trans tunnel which has lost a lot of insulation since the rebuild. While I’m fixing that, I intended to do the entire floor and doors etc.

I’m switching the snorkel to a ram head also. If it didn’t require a new guard panel, I’d gladly swap it for a safari. Live and learn.
 

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GUII ZD30DI Wgn
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A trap many fall into, I know of a guy who had one fitted with the head pointing backwards and his missus spat the dummy so it was cut off and turned around. And there's no HP in it.

I don't think you need to remove the dash to quieten it down, internal noise supression has been done by many successfully without going to that extent.
 

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The stock is. 3” with cat and muffler. The noise is almost entirely from the STUPID stainless steel snorkel. What a waste of money that was.
Also a lot of noise from the trans tunnel which has lost a lot of insulation since the rebuild. While I’m fixing that, I intended to do the entire floor and doors etc.

I’m switching the snorkel to a ram head also. If it didn’t require a new guard panel, I’d gladly swap it for a safari. Live and learn.
I reckon you'll get great results with those tweaks. I'll eventually do a snorkel, it will be a 4in ram head. Apparently those rear facing ones give nothing over a plastic one.
 

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GUII ZD30DI Wgn
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09 ZD30 CRD Wagon
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Discussion Starter #7
Thanks guys.

Yeah I have heard a 4” stainless with ram head is much quieter than the rear facing, but still louder than a plastic. Unfortunately I can’t easily swap to a plastic without a new guard, which is too expensive to bother.
100% agree there is no performance gain unless chasing dangerously high numbers.

I’m considering trying to stick some of the sound deadener to the inside of the snorkel itself to cut down on the resonance. Will apply some to the outside of the internal 4” pipe as well as the outside of the steel airbox.

I’m going to use adhesive butyl mat (like dynamat) direct on the steel of the cabin, then car builders “mass noise liner”, then factory carpet on top. In fact I may just buy one of their 4wd wagon kits which includes everything.
 

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Thanks guys.

Yeah I have heard a 4” stainless with ram head is much quieter than the rear facing, but still louder than a plastic. Unfortunately I can’t easily swap to a plastic without a new guard, which is too expensive to bother.
100% agree there is no performance gain unless chasing dangerously high numbers.

I’m considering trying to stick some of the sound deadener to the inside of the snorkel itself to cut down on the resonance. Will apply some to the outside of the internal 4” pipe as well as the outside of the steel airbox.

I’m going to use adhesive butyl mat (like dynamat) direct on the steel of the cabin, then car builders “mass noise liner”, then factory carpet on top. In fact I may just buy one of their 4wd wagon kits which includes everything.
Dumb question but is the snorkel itself isolated in anyway from the cabin?
 

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Jack, I have used the cheaper alternative to Dynamat, I used stuff called Underdog on all of the firewall and transmission tunnel and rear floor back above the exhaust pipe. I did it all on the engine side of firewall and underside of the floor. I then used the Car Builders brand stick on heat shield to do all the lower area of the firewall behind the exhaust dump pipe and along the transmission tunnel particularly where the pipe is close to the floor. This has cut a lot of the exhaust drone noise, but I still want to use the Mass Noise liner under the carpet and get rid of the old felt hessian type underlay.
516474
 

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Funnily enough I also have the stainless steel snorkel still sitting in the shed ready to fit, but just not ready to commit yet because I hear so much about the noise issues and really don't want it to be any louder. It is a short cut top on the snorkel as I had intended to fit my own Ram head when I can get the shape right.
 

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09 ZD30 CRD Wagon
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Discussion Starter #12
Jack, I have used the cheaper alternative to Dynamat, I used stuff called Underdog on all of the firewall and transmission tunnel and rear floor back above the exhaust pipe. I did it all on the engine side of firewall and underside of the floor. I then used the Car Builders brand stick on heat shield to do all the lower area of the firewall behind the exhaust dump pipe and along the transmission tunnel particularly where the pipe is close to the floor. This has cut a lot of the exhaust drone noise, but I still want to use the Mass Noise liner under the carpet and get rid of the old felt hessian type underlay. View attachment 516474
I really wish I had thought to do the same when I had my engine and transmission out!!

Regarding the snorkel, my two bob is that it is just not worth it. The aesthetics and the novelty wore off in less than 5 minutes. There’s zero performance gain over a plastic unless you’re chasing huge HP numbers.
Mine also is a “low cut”, and it points right at the passenger head. My ears were ringing after my last weekend trip. Forget about listening to any kind of talk radio or podcast. Music doesn’t help. I doubt sound deadening would help all that much, as the noise is coming in directly through the glass window. Expensive to reverse the process as you need a new guard + painting etc.

If it were me, I’d sell it and spend it elsewhere.
 

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If the noise is from the snorkel resonating, would something like a raptor coating help?
 

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I don't think it's a resonance thing nearly as much as it is a straight up roar from the air entering the end of the pipe.
 

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I really wish I had thought to do the same when I had my engine and transmission out!!

Regarding the snorkel, my two bob is that it is just not worth it. The aesthetics and the novelty wore off in less than 5 minutes. There’s zero performance gain over a plastic unless you’re chasing huge HP numbers.
Mine also is a “low cut”, and it points right at the passenger head. My ears were ringing after my last weekend trip. Forget about listening to any kind of talk radio or podcast. Music doesn’t help. I doubt sound deadening would help all that much, as the noise is coming in directly through the glass window. Expensive to reverse the process as you need a new guard + painting etc.

If it were me, I’d sell it and spend it elsewhere.
Also should have retained plastic snorkel to compare with current setup, but does draw so well with 4" SS snorkel.

Not sure of your induction setup (snorkel thru to turbo), mine is safar ram hd 4" SS snorkel to 4" thru alloy rectangular airbox w/9" pod and 3" SS pipe to h/f turbo. Initially was so loud (air getting sucked in under load), but certainly not as loud as when I turned the ram hd 180°(rear facing). I have done a few thing to reduce the heat soak happening with induction, introduced exhaust wrap and wet suit sleeves with gold reflective tape over pipe from air box to turbo, foil backed over butyl rubber sound deadening with weighted vinyl on and around airbox including top.

Have not got around to it yet, but may put exhaust wrap around snorkel and apply some "High Temperature (HT) Silicone Coating" over wrap to seal .

Certainly got some ideas from forum and conversing with @geordie4x4.

If u have a roof rack, maybe there is an opportunity for a couple of elbows and an extension pipe to place an air ram just aft of windscreen, and in front of roof rack. Have not given up on the idea. My M/T tyres are louder now with windows up so gained improvements.
 

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09 ZD30 CRD Wagon
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Discussion Starter #16
Jack, I have used the cheaper alternative to Dynamat, I used stuff called Underdog on all of the firewall and transmission tunnel and rear floor back above the exhaust pipe. I did it all on the engine side of firewall and underside of the floor. I then used the Car Builders brand stick on heat shield to do all the lower area of the firewall behind the exhaust dump pipe and along the transmission tunnel particularly where the pipe is close to the floor. This has cut a lot of the exhaust drone noise, but I still want to use the Mass Noise liner under the carpet and get rid of the old felt hessian type underlay. View attachment 516474
Also I should add, I think you'll have a huge difference if you add the Mass Noise Liner. From all the reading I've done, you need the butyl liner such as dynamat etc (which you've done) to cut the resonance, and then you want a heavy sound barrier to replace the standard underlay.
The ideal barrier is two materials sandwiched together. Mass Loaded Vinyl and Closed Cell Foam.

From the sound deadener showdown site which has closed down.
Even though closed cell foam (CCF) and mass loaded vinyl (MLV) are used together when building a barrier, they do very different things.MLV blocks sound. It is a heavy, limp barrier. CCF is a decoupler. It keeps one thing from touching another - a gasket. CCF doesn't block sound and it doesn't absorb sound. It will stop vibrations from traveling between two objects - sheet metal to barrier, sheet metal to trim panels are probably the most common. CCF without MLV in any other application, under a carpet, for example, is almost certainly doing nothing

Carbuilders mass noise liner is exactly that... MLV and CCF joined together. I had a good chat with them the other day. I was wondering why in their "4x4 kits" they include the MNL Lite as well as the regular MNL. They tell me the Lite version is a lot easier to form to the spaces around footwells and trans tunnel and to fit the factory carpet on top, but they include enough of the regular thicker MNL for the rear cargo area in the kits.
The more expensive 4x4 kits also include "insul-layer", which will stick to the inside roof panels. From what I can tell, the kits are a good purchase but probably include too much of the stage 1 butyl liner, as 100% coverage is not needed to cut the resonance. Here's a really clever video showing it in action

 

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I did mine with dynamat. I bought a trim removal set, completely removed all interior except the dash. Even did door inner / outer panels (especially behind the speakers) and rear quarter panels. Took my wife and I two weekends to do, but so worth it. Car is heaps quieter, even at highway speeds. While doors were apart I replaced the factory speakers with some better ones. Sounds so much better now. Cost me about $650-$700 for all the dynamat, not cheap, but to me well worth the time and money.

54146D4D-7AE6-45BB-AF71-3EFD0AAA4C4E.jpeg


7E2EC8A4-5390-491A-B6CA-72123804F572.jpeg
 

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A trap many fall into, I know of a guy who had one fitted with the head pointing backwards and his missus spat the dummy so it was cut off and turned around. And there's no HP in it.

I don't think you need to remove the dash to quieten it down, internal noise supression has been done by many successfully without going to that extent.
 
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