Soundproofing in boot

[nebw]

Would a few of you mind checking something for me ? My Mk6 GT seems to have no meaningful soundproofing in the boot. There's just bare metal under the (thin) boot carpet and behind the (thin) moulded textile mat covering the rear wheel arches. I'm getting more road noise than I expected, even on 18s, and I wonder if I'm missing some soundproofing. In contrast there's thick matting under the carpet in the passenger compartment.

Would anyone mind taking a few pics of their boot area, especially showing what's under the boot carpet and - as far as possible without dismantling plastic trim - what's behind the wheel arch covers ? Would be much appreciated, cheers.

[maisbitt]

What you describe is standard for boot trim. If you've got your back seats down or your parcel shelf isn't in use (trip to Ikea perhaps?) you'll get a lot more road noise. The parcel shelf and rear seats are your main soundproofing of the boot.

[nebw]

Thanks for the reply.

I suspect the parcel shelf may actually do more harm than good as far as noise goes. If you slap it in the middle, you'll hear that it booms/resonates at a similar frequency to the vibrations that come through the suspension from the tyres. It's a giant passive subwoofer ! I'll be lining mine on the underside to damp it.

[maisbitt]

Dont slap the trim then.

When I have had the back seats down and the parcel shelf off (for DIY supplies, trips to the tip, etc), you notice a hell of a lot more road noise than when they're up.

[ralferoo]

Dont slap the trim then.... especially not when driving at the same time. :p

[nebw]

I think I've been spoilt by past cars. The last VW I owned was a Phaeton. Silent and brilliant at 100 on the motorway, but rubbish in Tesco car park.

I really wish someone would build something as practical as a Golf and as quiet as an S-Class/Phaeton. It can be done, and it would probably only cost them about £1k extra in terms of:
- reworked suspension mounts;
- laminated side glass;
- triple door seals;
- better deadening of large panels;
- foam inserts in body cavities/under carpet.

If they were equally quiet on the motorway, I'd pick a £(20+1)k Golf over a £40k Phaeton any time.

VW's publicity and press junkets for the Mk6 Golf actually attempted to suggest that the Mk6 was gaining some Phaeton-esque refinement. After 2 weeks driving a Mk6 I have to say that's bo**ocks ! Wind and engine noise are well contained, as is airborne tyre noise, but that's true of most modern £20k cars.

Structure borne noise, i.e. vibration up through the suspension into the body and then radiated into the cabin through everything that's attached to the body, is poorly dealt with, certainly on a GT with 18s. It's noticeably worse than, for example, an A4 S-Line on 18s I drove this morning and also worse than our other family car, an S-Max also running on 18s.

If you look at the rear suspension, the top of the damper is bolted into the top of the wheelarch, straight metal to metal, at a point that is hardly covered or damped at all in the interior of the vehicle.

I'm wondering whether Koni FSDs might help here. They're more absorbent of the small rapid shocks caused by rough road surfaces, while resisting longer duration greater magnitude forces imposed by braking and cornering. Koni don't list them for the Mk6 yet. Probably a good match for the GT's factory springs.

Anyone else looked at Koni FSD's, on their Mk6 or a previous Golf ?

[ptolemy]

You're excessive noise will be down to the large wheel / low profile tyre combination that you have. I used to drive Phaetons and Golfs when I worked for VW and fully agree that a small car with luxury car refinement would be perfect. I have not driven a MK6 but with the MK5's I used to drive there was a noticeable reduction in refinement when you went from a Golf SE / Match (15in wheels / 65 section tyres) up to a GT with bigger wheels, lower profile tyres and lowered, stiffer sports suspension. I always used to want VW to put the 2.0 tdi engine in the SE but it never happened with the MK5. One other thought regarding in car noise / boominess; Do you have leather seats? Most cars with leather seats are less refined than with cloth seats due to the way sound is deflected / absorbed by the respective materials. It's not an obvious thing and none of my colleagues picked up on it but for me it made a significant difference going between a leather and cloth upholstered Golf. Try an 'S' spec Golf and, despite it being the cheaper option, you'll probably find it the nicer car to be in on the motorway. It's not just Golfs. Friend of mine had a Mini Cooper S with leather seats / big wheels. He was fed up with the lack of refinement and so I told him to try a basic Mini One. He did and couldn't believe how much more relaxing it was to drive. Often, less is more my friends.......

[nebw]

Hi Ptolemy

Thanks - very useful thoughts. I do indeed have 18s, GT suspension and a leather interior. You're right that the leather makes a difference too. I still expected the car to at least be as quiet as, say, an A4 S-line on 18s with leather, but it falls short.

I've just bought a set of MkV factory 15s on ebay and will fit them Monday. It will be interesting to see how much difference that makes.

Perhaps there's a niche market out there for someone to strip Golfs back to the metal, including taking the dash out, to soundproof them properly, then stick them back together. I know ICE shops do it all the time, but they're aming at reducing bass distortion, and they're aiming at a different market.

I can strip the interior -excluding the dash - back to the metal in about 4 hours, but then it's really hard work making sure any materials you add don't get in the way of the trim when you refit it, particularly holes for wiring loom clips, pop-fit fasteners etc. Someone doing it to a large number of cars could make templates and speed the job up.

Yes - a small car with luxury car refinement. No 18 way massage seats, no pointless 4wd, no overcomplicated climate control or MMI type interfaces, no pointless trinkets appealing to the vanity of preening middle aged executives, but good quality engineering and refinement. Might have to give up the day job and have a go.

[nebw]

Just on the subject of the Koni FSDs, I'm chatting to Awesome GTI about them. They think the MK5 ones may fit, but I'm sending them the part numbers for the Mk6 GT factory dampers and they're going to check.

I understand the rear suspension structure was modified from Mk5 to Mk6. Anyone know how exactly ?

[maisbitt]

The 18" wheels are definitely the biggest contributor to noise on your car.

On my Golf GT Sport with 17" wheels, the ride was harsh and crashy at times, with noticeable tyre roar.

My new Scirocco definitely seems a big improvement on sound insulation, but the tyre roar is louder than the Golf on 18" Interlagos, or is it? Everything else is so well insulated, so all I can hear is the tyre roar, but I have perfect ride comfort (as good as it gets on 18" rubber) - that ACC does a brilliant job, despite the 18" wheels - ride is as comfortable as a MK5 Golf SE on 15" wheels.

VW will never offer the £1000 upgrade that nebw suggests, because when the car is sat in the showroom, no-one will be any the wiser, and won't see why the car costs a grand more than it used to. VW will also prefer it if you bought a Phaeton, not a bad 2nd hand buy with the hideous depreciation.

There is a noticable improvement in refinement on the Scirocco and the MK6 Golf over the MK5, but VW undo some of that good work by putting larger wheels on which will always give more tyre roar and less comfort. The ACC goes a long way to redressing the balance though.

[nebw]

Have tried it on the set of 15s that turned up this morning. It's definitely quieter, but the 15s look daft on a car that is otherwise so gorgeous looking, and the handling is definitely compromised. I suspect the suspension is tuned very specifically to the wheel size fitted at the factory.

So, coming to the conclusion that the car is as it should be but it's just not for me. I'm looking for a level of isolation and refinement that just can't be had in the Golf class.

Going up for sale now. Someone's probably going to get a bargain....

[Robbie G]

On my Golf GT Sport with 17" wheels, the ride was harsh and crashy at times, with noticeable tyre roar.
...
The ACC goes a long way to redressing the balance though.

Mk5 or Mk6? edit - sorry GT Sport must be Mk5 I presume.

I've got a Mk6 GT (petrol) on the way with 17" wheels as I felt that the test drive I had on the 18" wheels were a bit severe. I almost went for ACC but decided not to bother due to cost. I hope I don't wish I had bothered when my GT arrives!

I presume it's still comfortable for long motorway journies and that the suspension won't be too harsh on the GT.

[maisbitt]

RobbieG: It was a MK5. Before I had a Scirocco test drive, i'd have never thought that a car on 18" rubber would be any better handling than the harsh ride of the MK5 on 17" rubber. How wrong I was! I'm sure it's a 50:50 thing between the chassis improvements over the MK5 Golf for both the MK6 and Scirocco, and the ACC.

I would never have priced in the ACC on paper, but as it's included on the Scirocco I have it. Now i've had it, I would say that it could well be worth paying for on a Golf.

[maisbitt]

Nebw: The revised multilink rear suspension on the MK6 Golf is a simplified version of that on the MK5.

I don't know whether that makes it slightly inferior or not, but the MK5 set-up had too many components for VW's liking, and extended the build time by quite a way. The build time for a Golf has apparently been shorted by 4 labour hours as a result of the new set up.

It seems as though you want the big car smoothness from a car as small as a Golf - you might have to look at something along the lines of an A4 or a Superb to do it. So the Golf ride isn't something you can live with for a year or 2? You'll lose a small fortune getting rid so quickly.

Maybe you should get a test drive in a Scirocco to get a feel for the ACC system (as I doubt many Golf demonstrators will have this on). Maybe then you'll have an idea whether ACC could work for you in a Golf?

If ride comfort and noise are your priority then you'll be excluding BMW from your list of maybes, those run flat tyres are awful for ride quality and comfort.

Any chance of getting the suspension detuned on your Golf? Like 17" wheels on the spring set-up more accustomed to an SE?

[ptolemy]

Also, different brands of tyre of the same size make a noticeable difference. There have been various tyre tests done by the main motoring magazines who record noise levels form each tyre. Don't have a link to hand but I found one a while ago pretty easily with a google search. Road surfaces also make a massive differene. Often motoring magazines write a report about how quiet a car is in terms of road noise. That report will often have been written following a drive of a new model on smooth European roads. As soon as the car is driven on the cheap and nasty rubbish that too many of our roads are covered in, the refinement goes out of the window. It's partly why some manufacturers have started to bring their cars to Britain for testing.

[kodkod.84]

If road noise is ******* you off, you obviously haven't got the radio up loud enough :biglaugh:

[nebw]

Have just traded in against an ex-demo A8. Got the same as I paid for it despite a scratch on the wing and a few more miles on the clock, so everybody's happy.

Thanks to those of you offered help/suggestions (!). Enjoy your Mk6's and wave to me when you see me wedged tight in a supermarket car park somewhere.