Decibels of Cars and Coffee

I was playing around with a decibel meter today during Cars and Coffee and here are the results. The readings were taken from the rear of the car at idle and at a distance of approximately 3 feet away:

1995 Lotus Esprit S4s with Quicksilver exhaust and stock cats: 87.8 dB/100.7 dB (A weighted/C weighted)

1995 Ferrari 348 Spider with Nouvalari SuperSport exhaust and Sport Cats: 94.8 dB/106.8 dB

2002 Ferrari 575 with Tubi, stock cats and resonators removed: 96.8 dB/109.4 dB

2005 Ferrari 430 Coupe with stock exhaust: 84.1 dB/97.9 dB

2005? Kermit the Porsche (Porsche 997.1) with Tubi exhaust and Tubi header: 74.3 dB/93.3 dB

 

To clarify, that's 202 and RT 1.

 

Yes, I'm planning on being there.

Negative, picked up a standalone decibel meter off Amazon.

 

Couple readings to add to the list today:

1999 Ferrari 360 Modena with Nouvalari SuperSport exhaust: 93.1 dB/108.8 dB

2006 Lamborghini Gallardo with Tubi exhaust: 84.2 dB/98.8 dB

BTW, the reason I started to wonder about all this is because Delaware has a 96.5 dB limit for you to pass the annual State DMV inspection and yes, they do measure apparently with a meter.

The Full List:
1995 Lotus Esprit S4s with Quicksilver exhaust and stock cats: 87.8 dB/100.7 dB (A weighted/C weighted)
1995 Ferrari 348 Spider w/Nouvalari SuperSport exhaust and Sport Cats: 94.8 dB/106.8 dB
1999 Ferrari 360 Modena with Nouvalari SuperSport exhaust: 93.1 dB/108.8 dB
2002 Ferrari 575 with Tubi, stock cats and resonators removed: 96.8 dB/109.4 dB
2005 Ferrari 430 Coupe with stock exhaust: 84.1 dB/97.9 dB
2006 Lamborghini Gallardo with Tubi exhaust: 84.2 dB/98.8 dB
2008 Porsche 997.1 with Tubi exhaust and Tubi header: 74.3 dB/93.3 dB

 

That's the problem, I think the only law in writing that I've seen is probably the same one you looked at, Title 21, Section 4311, "No person shall drive a motor vehicle, including a motorcycle, on a highway, including residential streets, unless such motor vehicle or motorcycle is equipped with a muffler in good working order and in accordance with manufacturer's specifications and in constant operation to prevent excessive or unusual noise." Specifically the "...to prevent excessive or unusual noise" part that is open to interpretation. (For the record, SEMA actually adopted a 95 A weighted decibel limit.)

Between that sentence, the law that seems specific to motorcycles, "Maximum allowable A-weighted sound levels based on measurements taken at a distance of 50 ft from center lane of travel or 20" from exhaust outlet (Sec. 71-II-4. Allowable Noise Levels): 1) Highway Operation less than 35mph--78-80dba; 2) Highway Operation above 35mph--82-84dba; 3)Stationary at 50ft 78-80dba; 4)Stationary at 20'--95dba." and the inspection employees at the DMV (if you have ever gone through Delaware DMV inspections, you guys know what I'm talking about) I think they're actually making up their own rules...ahem, utilizing their own interpretations of the laws when inspecting vehicles.

I have only heard from Jon formerly of the yellow Barchetta and now of the Scuderia's experience when he had the Barchetta inspected way back when with a Capristo and this posting from a Ford GT owner:

"Having just been to DMV and failed the noise test by a mile(106db@2500RPM), I was wondering what the legal db level is in other states. Delaware DMV quoted 95db over the phone, and 96.5db at the inspection lane. Is that number in line with other states?"

Granted, speaking with my LEO friends, not one has been able to cite a specific number. (They all do not spend their time pulling people over for loud exhausts either.) However, again, you know how our inspection people at the DMV are...I think they actually get bonuses based on how many vehicles they can fail.

Anyways, I'll try to get someone out there in DMV land to clarify.


References:
http://delcode.delaware.gov/title21/c043/sc01/index.shtml

http://www.ehow.com/list_7264034_loud-exhaust-laws.html

http://www.riderzlaw.com/Motorcycle-Info/Motorcycle-Laws/Noise-and-Emissions/Noise-Polution-Standards-By-State.aspx

http://www.gt40s.com/forum/all-gt40/14182-street-legal-decibel-limits.html

 

I'll keep the meter in my camera bag, I can get a reading off your car next time we're both at C&C.

 

Yeah, but unless you're going to go really loud, you wouldn't really have to worry about it. Even Andy's 575 was just barely above the limit at 96.8.

 

I'm bringing this back! Couple new additions to the list...although, it's the same car, different setups and exhausts. I'll give myself all of a week or two before I get around to getting a reading with the valves open on the new exhaust.

Measured on my car:
1999 Ferrari 360 Modena stock: 77.6 dB/89.3 dB
1999 Ferrari 360 Modena with stock valves open: 82.7 dB/91.5 dB
1999 Ferrari 360 Modena with factory Racing/Sport Exhaust: 84.2 dB/99.3 dB


The Full List:
1995 Lotus Esprit S4s with Quicksilver exhaust and stock cats: 87.8 dB/100.7 dB (A weighted/C weighted)
1995 Ferrari 348 Spider w/Nouvalari SuperSport exhaust and Sport Cats: 94.8 dB/106.8 dB
1999 Ferrari 360 Modena with factory Racing/Sport Exhaust: 84.2 dB/99.3 dB
1999 Ferrari 360 Modena with Nouvalari SuperSport exhaust: 93.1 dB/108.8 dB
1999 Ferrari 360 Modena stock: 77.6 dB/89.3 dB
1999 Ferrari 360 Modena with stock valves open: 82.7 dB/91.5 dB
2002 Ferrari 575 with Tubi, stock cats and resonators removed: 96.8 dB/109.4 dB
2005 Ferrari 430 Coupe with stock exhaust: 84.1 dB/97.9 dB
2006 Lamborghini Gallardo with Tubi exhaust: 84.2 dB/98.8 dB
2008 Porsche 997.1 with Tubi exhaust and Tubi header: 74.3 dB/93.3 dB

 

They are measured post warm up. When are you doing your resonator delete? I can just bring the decibel meter to the next C&C.