997 C2S track DB

[Lewhar82]

Hi Guys,
I have just been to Brands for a track evening And failed noise test!
Tried looking up some info on DB noise tests on here but couldn't find anything definitive so wanted to inform anyone atttending a track day in general that a 997 C2S when tested at 5000rpm the DB is 101-102 with Sports OFF.

Cheers,

Lewis

 

[JCX]

Accepting that the 'general' figure above is an average of many cars what did yours register?

 

[Lewhar82]

Mine registered 101.2 @ 5000rpm and he had asked me to push it to 5250 which would have tipped the 102db!

 

[ralphmusic]

Noise tests are a pain but we have to endure...

The results are very variable, below for the same car over 18 months at circuits that test..

Goodwood 150501 - 101db
Rockingham 150512 - 100db
Goodwood 150526 - 101db (>101db drive by)
Castle Combe - 150528 - 101db
Castle Combe - 150625 - 98db but only asked for 4.8k revs
Castle Combe - 150723 - 97db
Goodwood - 150804 - 101db
Goodwood - 151205 - 95db
Goodwood - 160227 - 95db
Goodwood - 160323 - 98db
Castle Combe - 160623 - 102db
Castle Combe - 160721 - 100db
Goodwood - 160804 - 101db
Castle Combe - 161028 - 102db
Goodwood - 161203 - 97db (but 101.2db drive by)

I have given up on Goodwood, Brands I will fail drive-by.

Make sure engine is warm, aircon off, sport exhaust off, slowly build revs lest you go over 75% of max revs before steadying at 75%, watch out for cars behind being too close, keep lucky rabbit foot in glovebox, etc..

 

[JCX]

What is the noise limit?

 

[Lewhar82]

Tonight was 98db but other evening Ines are 102db. Daytime ones are fine.

 

[JCX]

Very good to know thx.

 

[tscaptain]

I reckon 911s are at a disadvantage with noise tests as the engine mechanical and intake noise is not insignificant at 5000rpm added to the exhaust noise. Not an issue with front engine cars? Do they make an allowance for this? Not in my experience.

 

[JCX]

Just track during the day

 

[waxman]

I would have been surprised if you had passed at 98db .
when I was at Castle Coomb last month I was tested at 102 db (was a 105db PCGB day so ok ) and out of interest asked them to retest with the sports exhaust turned on - result 102db - go figure
tony

 

[Geoff_Fields]

I think you'll find that the sports exhaust valves open at 3000rpm in "quiet" mode and permanently open in "loud mode" so will return same results no matter at 5000rpm.
At least this is true for my GT3. I have a Carnewal remote control gizmo so can select permanently quiet if required.
http://www.carnewal.com/p...084/PSE-Manual-Control

 

[tscaptain]

At least this is true for my GT3. I have a Carnewal remote control gizmo so can select permanently quiet if required.

Quiet? Oh, I see, relatively speaking.....[]

 

[nickw1968]

I went to a track day at Thruxton recently which has a noise limit of 90dB. My 997.1 C2S has a PSE.
i was really concerned that I'd fail so I agreed with the organisers that I'd only pay for the day once I'd passed the noise test.
Well the test at 5200 RPM showed 98dB. I said to them I was at a disadvantage with a 911 because the engine is at the back so all the mechanical noise was contributing to the overall noise produced from the exhaust, which wasn't the cars with the front engine cars. They agreed to re-test holding the measuring device a bit further back from the car, but this still produced a 96dB reading so I failed.

i decided to spectate for a while and listened to some cars circulating that were definitely louder than my car when driving past. So I went to the organisers and they suggested a drive by test. They let me on track for 3 laps and held the listening device by the start/finish line at track level and I passed with a dB of 89.

So it seems there is some flexibility out there and it will depend on the organiser and noise tester and equipment they use as to whether they will be flexible in testing.

It looks as though there wasn't much flexibility though for Lewhar82!

 

[ralphmusic]

I took my 997 GTS to a Goldtrack day at Thruxton three years ago. Obviously Melindi had influenced the noise test man as he said "take it up to 4k" and he then said "good news it was 89db"