SanDiegoDavid

Wanted to know if anyone has information about this. I'm about to do a local Autocross at Qualcomm. There's a 93 dB limit.

Mike in CA

Our site has a 92db limit and I had no issues a couple of weeks ago but I'm not sure how stringently that is enforced. At least it didn't raise any obvious flags. Like David, I'd be interested if someone has real numbers.

SanDiegoDavid

Thanks Mike.

MayorAdamWest

Laguna? I blew 92dB with a 991S. Though, it seems to really depend on the day and humidity.

Carrera GT

I doubt you'll be making a lot of noise on an autocross unless it allows for 100 mph wide open throttle sections, up-hill, next to a sound check booth ...

I did a 90 dB day at Laguna with this formula:
* Sharkwerks turnips (from my old 997.1 GT3, no heat shield, but a bit longer and thicker stainless than some other people have copied)
* lift-n-shift (rpm below 7000)
* stay middle-to-left track
* about 60% throttle
* PDK in normal (not Sport) mode
* exhaust in normal (not LED on) mode

PDK does a brilliant job of driving this way -- just leave it out of Sport mode and in auto -- you manage the up-shifts and it quickly reasserts itself (unlike the Carrera programming which will remain absurdly hands-off for far too long after a manual shift) and blips down through the gears into the next turn just perfectly -- not early, not late, doesn't upset the car at all. If you upshift a little early or you anticipate wanting "all ahead full" you can hold the downshift paddle and PDK will rap-rap (as Andreas tends to put it) and give you a delightfully clean spot in the meat of the torque curve in 1st gear.

You're not going to set a personal best on a dB limited day at the track, but for an autocross circuit, I don't see the potential for trouble in sound pressure. At least for Laguna, you can go flat chat all around the place except for the soup kitchen at turn 5.

I imagine the new GT3 will do sensationally well in a fast autocross (apex speeds around 40 mph) where the rear-steer really shines. If you can manage tire temps and stay off the fronts and away from terminal understeer, it should reward you with mind-boggling agility and stability with an ability to rotate and carry momentum through radical steering input and direction changes without excessive oversteer slowdowns. If only this car were 2900lbs ...

eilig

I've tried to get dB info directly from Porsche, with no luck. You would think that they would have this sort of info available, due to the intended use of the car, and the fact that more and more tracks are starting to pay attention to noise levels...

SanDiegoDavid

Me too. No info at all.

Nick

David, when is the event at Qualcomm?

Macca

There is at least one 991 GT3 owner in Europe who has the car down to 2980lb simply by removing the seats and replacing with recaro shells and installing a M&M full exhaust system....

Macca

Ive posted this before - its the official data from the factory that shipped with my car (the document is know as the Certificate of Conformity and is a legal requirement when registering the car for the first time in many countries).

Here is the original + the translation incase your German is rusty...

SanDiegoDavid

September 7.

SanDiegoDavid

96, pretty high. I wonder how close the microphone is during the measurements?

eilig

Exactly my question. I think some definitions around how the measurement was taken would be necessary in order for this to be entirely meaningful information.

Macca

This is the official manufacturer data lads which is lodged via PCNA when you car gets to USA. It's performed in the method used by Porsche and all euro manufacturers for sound pollution. That methodology is widely published if you care to use google. It's something like 950mm from rear of car....

orthojoe

96 sounds about right. I would have guessed 97dB.

Back when Laguna sound limits were 93dB, stock gt3 would not pass.