[matowi]

Originally Posted by min

Hi,

Thanks for the quick reply! About the color - congrats for yours too (yours seems also the Donington grey?); not to mention your incredible looking 21" rims (for the moment I remained on 19" for comfort reasons, I'll see in the future if I switch to 20").

Yup, mine's also Donington. However, unlike yours, my car has a light interior, so it's strongly leaning on the "bright" side of things (light color, light interior, non-blacked out grille and side decor elements)

Originally Posted by min

One more test that I did and which might be helpful in your case: I attached a suction-cap phone holder on the driver's window and pulled it towards the interior of the car while driving. The purpose was to understand if the door is not sealing/pressed enough against the car frame/seals and me pulling it would seal it better; though it didn't seem to improve (perhaps just a little bit) - that's why I still suspect/hope it's from the window seal which is not 'embracing' correctly/completely the whole window...

This seems like a nice way to test the seals. I'm stealing the idea!

Originally Posted by min

One last word about the additional car body sound-proofing: (...) my advice is to try and test 2 similar cars/models (like also a G31 without sound-proof and then your brother's car) in order to take a better decision and adjust your expectations from the sound-proofing. If you conclude that the noise comes mainly from the windows/doors seals - I guess the acoustic glass would be the solution for you. Also you mentioned that that specific workshop can help also in improving the door/windows seals?

So, I did a back-to-back test with my brother's car. Same road, same conditions, we drove first in his car (with the super-duper sound proofing job done) and then mine. The difference was audible with respect to his car being much better at keeping the engine hum and the noise of passing-by traffic out of the cabin. However, even in stock form, my car is quieter when it comes to tyre roar and front screen noise. However, the fact that tyre noise was lower in my car may have more to do with the actual rubber than with the cars' sound insulation capabilities. I'm running BMW recommended Pirelli Sottozero 2s (with * etc), which in the BMW-spec are among the quietest winter tyres money can buy. My bro has some ultra high performance winter continentals, without BMW * (but with other parameters meeting OEM's specs). I bet they're much louder by themselves. Tyre widths are the same on both cars - 245 in the front and 275 in the back; side walls were also the same; however, mine are wrapped around 20" rims, my brother runs on 19"

Back to the wind noise, I'd say that around A-B pillar area it is exactly the same in both cars: it's a non-issue until ca. 70-80 km/h (45-50 mph), gets noticeable but not extremely annoying until ca. 100 km/h (60 mph), and gets on my nerves from ca. 140 km/h upwards (ca. 90mph). Which leads me to the conclusion that my Volvo V90 with acoustic glass was extremely quiet - to such an extent that top-of-the range bimmers with standard glass simply don't keep up

Based on your comments, I think I will pay a visit to an independent glass shop or some used parts dealer and enquire about double side window panes. I'm reluctant to change the windscreen though... Probably, I'll keep it in stock form, unless I'm forced to change it after some stone chip or similar damage requires that a new screen is put in place

Originally Posted by min

Then definetly I would start with those (...) and, obviously, the costs will be much-much lower than the initial quote for the whole car's sound-proofing.

Not so sure about the cost... When I approached my local BMW dealer asking for a quote for the acoustic-glass front screen (with HUD capability), they said EUR 2500... so the front piece of glass would run me more or less the same as the whole car sound proofing. All-round glass would go into EUR 5k territory

Originally Posted by min

I would be confident that acoustic glass plus the door&windows seals extra insulation would do the trick for you.

Yup, that is the first bet; I'll do any soundproofing as a secondary option

Regarding your other remarks... In a 3-er or even a 5-er I would worry about the extra 30-40kgs that the insulation would add. In my 7-er, which is hardly a curve carver (especially with a heavy diesel upfront...) I won't be concerned at all.

Also, I am certain there's lots of sound-deadening stuff on the car in stock form. The back-to-back with my brother clearly confirmed that. Too bad BMW decided to not offer acoustic glass as standard on all 7s. I mean... who would object to a roughly EUR 1k price hike for a base model, if that made the car so much more luxurious? Most buyers wouldn't blink an eye

Originally Posted by min

Good luck with your tests and next actions, I'll post my results as soon as I have news.

Looking forward to your report