M758

Guys,
Some you may have heard, most probably have not.

Arizona Motorsports Park (AMP) is a 2.25 mile race track & 800x800 skid pad located in the glide path and high noise zone of Luke Air Force base in the Pheonix area. This track open in March of this year with no sound restictions. Based on a few complaints the count which governs the land on which the track sits has decided to re look at the track operating permits. The plan had been to conduct a sounds study from now through december to understand how much noise actullay came from the facility.

It appears that due to politics and big money from a developer looking to close the Air Force Base in the future that a sound study will not be allowed under the guse of sound studies being done elsewhere. To me this stupid as the acutal sound propagation is fucntion of the surrounding area and cannot be inferred from other places. In any event it looks like AMP will be saddled with some artifically derieved noise limits.

What are some common noise limits at places like Laguna, Portland, Lime Rock, etc. What is lowest you have heard of or had to meet. When does it become impossible or not worth it meet sound limits.

It appears those opposed to the track are thinking of numbers like 60 dB (no I am not kidding )

Thanks for your help!

Greg Fishman

OMG, 60db is ridiculous. A lawnmower wouldn't even pass that limit at a 100ft.

Howard

As far as Laguna goes, I know the db limit is 92 at 50', with 25 cars maximum on the track during club events. My personal preference is to make as much noise as possible, especially during a race. The other cars know when I'm at their side ,without viewing me in their side or rear view mirrors, and vice versa.
I think 60db's is rediculous, most street racer imports exceed that easily.

good luck !

Geoffrey

Lime Rock has an 87db limit and will let you go up to 89db measured at 50'.

Mike Buck

I was at Mont Tremblant recently for 4 days of DE. There the noise limit was set to be 87dB for a warning, and 89 dB for a black flag. I do not know if the officials were measuring, but I don't think anyone was in blatant violation. I like to pull my muffler for track events, but there I left it hooked up. The right muffler on any Porsche should put you right around this level. If not, just lift by the mic.

Around 90 dB would seem like a reasonable limit and that's probably on the low side for track that have limits.

Mike in Chi

Road America is 108 db

Hubert

That track will never get used! When I ran laguna with my "hon-duh" it registered at 90dB on the meter, with muffler on. And that was at the sound station b/w t4 and t5 on the uphill. The limit was 92dB , and had I run my "race" muff-less setup , it would have been well over 100dB at WOT.

M758

So what would you guys expect for a "street legal" car?

less than 90 dB?

FYI,
I found a website that meaured sound on the New Jersey Turnpike a 85 dB.

John Brandt

Mid-Ohio's 102db

Hubert

M758: My car is still "street legal" (i.e., cats, resonators, etc.) and it barely squeezed in at 90dB, and hit 91dB a couple time when I was really on it, and 89dB when I did a partial lift. So, yah, should be right around 90dB, for a street legal/emissions legal car.

NetManiac

When we have our autocrosses at the stadium, which is in a valley surrounded by whiny babies, it's 92db. I would suspect 87 to 92db would be a "reasonable" limitation, with maybe a few weekends a year where you can run unlimited (I believe I head Leguna Seca does that, right?). 60db's is crazy. I say you measure their car when they are leaving a stoplight sometime and cite them for exceeding the noise limit. Be militant! Run around town with a db meter screaming at all the old fogies that their Buick Regal is being too loud!

"Put a muffler on that thing would you grandma!!!"

Craziness I tell ya, pure craziness!!!

Hubert

NetManiac: Laguna is also surrounded by some "vocal" protestors to noise, and the only venus that run unlimited sound are the pro/concourse series; i.e., ALMS, WSB, Speed WC, CART, Historics, et. al. The rest of the days are strictly enforced.

HarryD

60 db. Ridiculous.

If the folks proposing that limit are capable of speach, they would not be able to speak in normal conversation! Do they not cut their lawns? Cite them when they start the mower.

I saw this article to help you understand what they are asking(http://www.customaudiodesigns.co.uk/...s/decibels.htm):

"UNDERSTANDING DECIBELS

The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet aircraft. In terms of power, the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound. That's a big difference!

On the decibel scale, the smallest audible sound (near total silence) is 0dB. A sound 10 times more powerful is 10dB. A sound 100 times more powerful than near total silence is 20dB. A sound 1,000 times more powerful than near total silence is 30dB. Here are some common sounds and their decibel ratings:



Near total silence - 0 dB
A whisper - 15 dB
Normal conversation - 60 dB
A lawnmower - 90 dB
A car horn - 110 dB
A rock concert or a jet engine - 120 dB
A gunshot or firecracker - 140 dB

<snip>

CarreraCup03

Maybe we should race those electric cars ... just under 60db. LOL.

944turbo

pig4bill

60 db? Pick up a Road and Track. A Cadillac at 70 mph measures 66 db or so on the INSIDE of the car. Take a couple Road and Tracks or Car & Drivers with road tests of a Corvette and a Caddy as examples of what real-world noise is made by a car.