Noise limits porsche 997.2S

[vfb86]

Hi All,
I signed up for a track day at Snetterton (first time ever) with MSV.

For Friday the limits are:
Static 105db
drive by: 92db

I'm just a bit worried my car wont make the test. I dont really wanna book instructor time and loose not only the ticket, but also the instructor's costs

Has anybody driven/ measured a 997 Gen 2 CS2 and what were your results? Should I be worried?

Many thanks

[brillomaster]

Have you modified your exhaust in any way? Does it have switchable sports mode? Still got the cats on?

If you have a standard exhaust, it'll be fine. 105db static is pretty loud. I had an old 300zx, decatted with race mufflers on. It was loud enough to wake the dead, but that only managed 99db static when tested.

[vfb86]

car has no modifications

It has a sport/ sports plus mode, but no sports exhaust (PSE)

what are cats? Catalyst? Not sure, it's just a "standard" unmodified 911 (997.2 CS2)

Edit: Will let you know the results afterwards

Edited by vfb86 on Wednesday 19th May 15:35

Edited by vfb86 on Wednesday 19th May 15:36

[braddo]

You'll be fine (or at least, I'll be amazed if you're not ).

The 997 GT3s are around 103-105 static and that's with exhaust valves open at around 6000 rpm (8400 redline).

911s tend to do well on drive-by noise because of the rear engine and not much induction noise ahead of the car. Compared to a hot hatch on throttle bodies they're very quiet!

[nickfrog]

As others have said, it'll be fine. If you have a MSV venue near you they normally do noise testing FOC although not sure with Covid etc...

[vfb86]

Thanks all
Result: 103db with 997.2 (2010) CS2 rpm@5,500 ish

[Ekona]

That seems extraordinarily high, I'm sure when I tracked my old 997.2 C2S with PSE I wasn't anywhere near that, certainly still in the 90's dB for the static. Given that the day in question was at Bedford which has limits of 101dB for the static, if mine had made the volume yours did I wouldn't have been allowed on and they're quite well known for being strict at Bedford.

Just goes to show how much a measurement can differ between tracks.

[vfb86]

Well... I didn’t check the measurement myself, but that‘s what I‘ve been told.

I would say the microphone was likely rather <50cm than 50-100cm away from the exhaust, and I rev‘ed it up perhaps a bit too quick than you would ideally to get a lower db measurement

[240Cup]

991.1 C2S with PSE (valves closed) was 98db on Friday with MSE at 4,500 rpm

[PGNSagaris]

vfb86 said:

Hi All,
I signed up for a track day at Snetterton (first time ever) with MSV.

For Friday the limits are:
Static 105db
drive by: 92db

I'm just a bit worried my car wont make the test. I dont really wanna book instructor time and loose not only the ticket, but also the instructor's costs

Has anybody driven/ measured a 997 Gen 2 CS2 and what were your results? Should I be worried?

Many thanks

You’ll find it gets to 100db. Won’t be a problem. Enjoy the day, it’s a goodie Snetterton

[phazed]

vfb86 said:

Thanks all
Result: 103db with 997.2 (2010) CS2 rpm@5,500 ish

You were too high, (revs). You must raise the revs very slowly so you don't pass their rev point of measure.

That was critical in my old 5.5 TVR. A couple of hundred revs over the figure would mean a fail.....

I did Combe a couple of weeks ago. 997.1 with sports mode.

4.5K revs, 90db
With sports mode, 94db