dB testing?
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 975
Likes: 67
From: Pleasant Hill Ca.
dB testing?
Does anyone know how to accurately test our exhaust decibel level on our cars? I am wondering if I should I measure the dB's from the road side as the car passed by me or what? In about a month, I will be running at Laguna Seca where their sound limit is 92. In comparison to our other two local tracks, this one is the lowest.
I have recently swapped out the exhaust manifolds on my '08 C6. to a GM Z06 pair. In addition I changed to the Z06 catted tubes and H pipe. Previously I put a Calaway CAI and now that it is linked in with these pipes it does have more oomph and louder sounds. Whether it is over 92 dB's is unknown at this point. I just do not want to get out there and be told I am above their approved level. Anyone here have concrete data on how this should be done?
I have recently swapped out the exhaust manifolds on my '08 C6. to a GM Z06 pair. In addition I changed to the Z06 catted tubes and H pipe. Previously I put a Calaway CAI and now that it is linked in with these pipes it does have more oomph and louder sounds. Whether it is over 92 dB's is unknown at this point. I just do not want to get out there and be told I am above their approved level. Anyone here have concrete data on how this should be done?
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Normally it is 50 feet off one side of the track right at a place where the cars are at WOT.
Contact that track and ask were the sound station is located
Most tracks do not monitor sound unless it is a race.
to give you an idea, an LS7 with the butterfly exhaust valve open will be OVER 92 dbs, butterfly valve closed is about 89 dbs,
You can also go buy some exhaust turn downs, 45* turn down, and point them away from the sound station.
This helps withe single exhaust / muffler per side set ups, vs four tips.
Contact that track and ask were the sound station is located
Most tracks do not monitor sound unless it is a race.
to give you an idea, an LS7 with the butterfly exhaust valve open will be OVER 92 dbs, butterfly valve closed is about 89 dbs,
You can also go buy some exhaust turn downs, 45* turn down, and point them away from the sound station.
This helps withe single exhaust / muffler per side set ups, vs four tips.
Last edited by AU N EGL; Aug 7, 2010 at 06:57 AM.
Melting Slicks
Joined: Oct 2007
Posts: 2,702
Likes: 192
From: Northwestern Connecticut
St. Jude Donor '10 thru '26
Actually many tracks are putting dB limits in, Lime Rock was at 92 dB and is now at 89 dB - a lawyer bought a house near the track and was pushing for 82. (go figure, buy a house by a track that's been in place for 50+ years and you might hear noise!) Anyway, I'm not sure if they still sell it but Radio Shack use to have an dB meter for around $30.
Turn-downs (pointed away from wherevery they are measuring) do work well. Also cone type inserts in the exhaust can help shave an extra couple dB if you are on the edge.
Turn-downs (pointed away from wherevery they are measuring) do work well. Also cone type inserts in the exhaust can help shave an extra couple dB if you are on the edge.
Race Director
Joined: Sep 1999
Posts: 12,437
Likes: 919
From: CONCORD NC
you can buy a sound pressure meter at Radio Shack, I have one for setting up audio equipment. Have someone stand by the side of the road and measure you as you come by at full throttle.
Even then, I'd be prepared with turn-downs, or other silencing devices.......working around sound issues DURING an event is one of the most frustrating things you'll ever encounter. During a World Challenge race at Portland in 2001, I had to go out and find a muffler shop to fabricate turndowns for me.
Even then, I'd be prepared with turn-downs, or other silencing devices.......working around sound issues DURING an event is one of the most frustrating things you'll ever encounter. During a World Challenge race at Portland in 2001, I had to go out and find a muffler shop to fabricate turndowns for me.
Safety Car
Joined: May 2007
Posts: 4,812
Likes: 46
From: Taylorsville North Carolina
Rd Atl has a 102db limit during church hours on Sunday. They check on the backstretch. They didn't say anything to me so I guess mine is OK. Doesn't sound that loud to me inside, but neighbors comment a lot
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Burning Brakes
Joined: Oct 2003
Posts: 1,090
Likes: 74
From: New Carlisle IN
Reminds me of a quote from the comedian Gallager that would apply here also: "Give the houses by the airport to the deaf people!"
