qbix

Is there any official data available?

Had some problems recently on a track day. The limit was 96dB (dynamic) and I was measured form 111 to 117dB.
The measurement was done on the final straight. Speed around 200km/h 4th gear. The car was stock.

I am asking as I have doubts if that was done correctly. The dB meter was positioned next to a long building parallel to the straight (pit lane) and on the other side of the track there was a long, about 3 meters high sand bank.
The sound wave could get somehow amplified by bouncing off the building's wall and the bank.

Shahano

Im pretty sure the stock GT3 does not do 111 dB. Sounds like alot.

sgroer

No way it does that much. At 50 feet from the track edge, the Sharkwerks is 100dB or less, the GMG which is LOUD is 105dB. Stock is something like 96dB.

Depends where they measured from, but if they measure some distance from the edge of the track, there's no way you were that loud. A nationwide stock car was 117db at my track.

qbix

Thanks. That is already some information that makes me willing to investigate what is going on with their measurement.
It is actually some society living next to the track making us the trouble. The funny thing is that there is an airport like 500m from the track with 737s and A330s taking off...
And the track had been there long time before any people moved in around!

usctrojanGT3

i think it's a little quieter than the .2RS.

Serge944

A GT3 can do 117 dB. No problem. It all depends how closely you measure.

You have a 6 dB drop every doubling of distance. 117 dB at 5 meters distance is typically 105 dB at 20 meters distance.

There are no standards for measuring track sound pressure levels, but of course ideally you want the mic to be in a place where it is not influenced by other objects at the track.

mwar99

Some of the measurement is going to be contingent on atmospheric conditions too. That will change how the sound registers. That said l, as Sean said - no way it's that loud stock. Maybe they got you at the same time a plane was taking off.

Serge944

I'm curious how many other cars were affected. I mean, if you had been measured at 20 dB over, I think that many other cars (if not all!!) would be over as well.

sgroer

to be clear - my readings in the post above are 50 feet from the track edge. We ran a lot of sharkwerks cars last friday at our smokies event at AMP. The cloud ceiling was very low and the air was thick. NYC_AREA_GT3 got flagged for sound, no other shark cars did. Their limit is 98dB 50 feet from the track. We wired the GMG cars valves shut as they do not pass sound at AMP. Wired shut it's something like 94db

MayorAdamWest

At Laguna Seca, the factory exhaust hits 102dB at full throttle. The booth is probably 30 yards from the edge of the track.

sgroer

Very surprising it's that high (but not doubting what you say). These dB readings are all over the map. So much depends on the acoustics, atmospheric conditions, etc. Concrete walls on the track for example would make a huge difference, sand pits probably absorb sound.

Very difficult to get a benchmark unless done on the same day at the same place in the same conditions.

Serge944

On a slightly different note, has anyone tried using "muffling tips?"

I'm curious how effective they really are. If they work as advertized (claimed 3-5 dB reduction) and you're just a couple dB from making sound at your local track, could be worthwhile.

sgroer

Buddy with a 997 GT3 and a bypass (not sure which one) does not pass sound at AMP without them, passes easily with them. They make a noticeable difference. His slip into the pipe and are secured with a set screw.

jlanka

I use those "cones" also. I got black flagged at Palmer without them (96db limit) and was OK with them

Clocked

If anyone is interested I have a brand new still in the box Sharkwerks exhaust for the GT3. $1,200.

Box had not even been opened. Decided not to put it on my GT3.

Thanks.