Dr.Bill

One of the local tracks has a sound restriction of 94dB. I was hoping to take the 991 there Saturday for the day. I had a 997 C2S with the standard exhaust that measured 88 or 89dB, so I figured the 991 would pass easily, even with the sport exhaust.

Boy, was I wrong! With the PSE on, it measured 94.7dB, just beyond the threshold. They let me try again with PSE off and it measured 95dB! Fortunately, my wife drove the Cayman R out and took the 991 home, so I had a great day anyway.

Another guy had almost the identical car (991 C2S) with the standard exhaust and he passed the sound tech easily. Stupid PSE!!

The good news is - I'll be taking it to a different track next weekend with no silly restrictions!

So, before ordering PSE, consider the noise!

Buddhabelly

I don't get it. Did I somehow misunderstood your post?

With the PSE OFF, it's louder? (95 > 94.7)

SiNi

Useful info, although don't understand why PSE loudest when off?

Most UK tracks have noise restriction from 95-105db so should be ok here!

trysixty

must be faulty decibal meter or they just have it set to read 95 or less to allow everyone to drive is my guess.

you are right the PSE is loud, great option to be able to turn off with wife and on with gf though

Dr.Bill

Nothing wrong with their sound meter. A turbo with an aftermarket exhaust blew a 106dB reading, so it's not set to pass everyone! The track faces heavy fines if the county reads too much noise, so they have a great interest in accuracy.

A 996 GT2 with stock exhaust will pass, a 997 GT3 will not (97 or 98dB). A 996 GT3 with cats removed passed. A couple Caymans passed with aftermarket exhausts. An M3 race car passed. I figured that a street car (the C2S) would have no issues.

And yes, it was slightly louder with PSE off. Basically, the PSE changes the tonal quality of the exhaust; it does not make it 'louder'. In fact, with the baffles open and more volume of air flow, it reads as slightly less sound pressure.

trysixty

If it's louder when the PSE is off, i'm going to tell my wife "the $3k noisy exhaust" is just a figure of her imagination and to call you if she doesn't believe it. Same with all the neighbors who take refuge in their homes when i drive the speed limit with the PSE on.

John 996 TT Cab

I'm lucky as my wife insisted on the PSE! In fact, the idea for whole new car (due to arrive in 2 weeks or so) was hers. We were driving on the Autobahn (Germany) in a rental 991S Coupe with the Sun roof tilted up at rear and PSE open (at about 125mph) and she turned to me and said "you should get one of these!" Came home and ordered next day.

Nicoli35

I really love the 991 PSE. Kind of makes me wonder why I'm putting Fabspeed side maxflo mufflers on for a bit more sound, but what the heck. I'm super-curious to experience what that will be like in person.. (we are leaving the PSE workings untouched and completely intact, just like Darren did)

chuckbdc

I have been on the fence about a refit, but now that I have the evidence I can say that I did it for the neighbors.

hlee1169

That does not sound right. When I tracked my 991S at Laguna Seca with sound restriction of 92db, I kept the PSE off and have never been flagged for sound level violation. Could it be that there's another car nearby that they have mistaken for your car?

Dr.Bill

No, they do the testing with only one car on track at a time. I thought the result was strange as well.

I was at red line in 3rd gear. Maybe if I peddled it in 4th it would pass? But then I would run the risk of a black flag and potential fine. Not worth it for me.

fantom

So I'm not nuts for enjoying the mellow soft tone of my PSE

chuck911

Those readings are close enough you should be able to pass with something simple like wrapping some asbestos wrap around the pipes. I've seen it done and it works. Your reading is close enough maybe even just covering the exposed exhaust pipe tips would do it.

oldman40

what were the rules of the sound test? did you have to be at redline?

hansw

In PSE OFF the valves open above about 3000 rpm, which means it goes into the same condition as in the PSE ON mode. In PSE OFF the valves are closed below about 3000 rpm and the car is quieter, but at high revs there is no difference between OFF and ON. At least that's how it works on my car.