John356

I just compared Car & Driver's road tests of a 2017 4S Coupe (no sunroof) and a 2017 4S Targa and was surprised to see that the Targa was 6 dBA quieter at 70 mph, the opposite of what one would expect. Both were equipped with 20" wheels with Pirelli P-Zero tires, and both had PDK. Might the Targa's extra weight or structural reinforcement somehow suppress road noise? I doubt that they would have tested the cars on different road surfaces, but it's possible that they did. In any event, 70 dBA at 70 mph is an impressive result for a 911.

Targa:
Idle - 53 dBA
Full Throttle - 85 dBA
70 mph - 70 dBA

Coupe:
Idle - 54 dBA
Full Throttle - 88 dBA
70 mph - 76 dBA

http://media.caranddriver.com/files/...4sauto2017.pdf

http://media.caranddriver.com/files/...rera4s2017.pdf

Needsdecaf

That's really strange.

bkrantz

As others have pointed out, noise at cruise is very sensitive to road surfaces. In my coupe, the noise level can change from very comfortable to obnoxious when crossing from newer smooth asphalt to older rocky asphalt. And the worse I have seen (heard) is grooved concrete.

randr

991.1TTS at idle 57db, 70 mph 72db, WOT 82db
991.2 S at idle 52db, 70 mph 71db, WOT 86db
991.1 base at idle 48db, 70 mph 76db, WOT 89db
991.1 GTS at idle 54db, 70 mph 75db, WOT 89db
981 GTS at idle 51db, 70 mph 77db, WOT 91db
991.1 GT3RS at idle 61db, 70mph 79db, WOT 108db

Decibels are measured via a logarithmic scale - so 80db is roughly twice as loud a 70db. Its worth noting that the permissible exposure time at 88db is four hours and at 100db its 30mins. (Its definitely worth using ear plugs on track).

budrichard

A different road surface and instrument calibration might account for the difference but they are different structures in the rear.
My 2017 C4S does not have a sun roof and tire/road noise is the dominant sound at 70mph.-Richard

MJBird993

A car with 100 miles is going to be a lot quieter than one with 9000 miles and worn out tires.