Modifying the Stock Exhaust?
Joined: Aug 2002
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From: St. Louis
Originally Posted by jguerdat,Feb 23 2008, 10:03 AM
Wanna meet our sound meter? Calibrated and all. 
The statement still stands: I doubt he will ever run into a sound meter, since there is no specific rule for noise, region noise regulations vary widely, and having any rule let alone a meter is rare.
Joined: Jul 2003
Posts: 13,471
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From: Upstate NY
Does he live in your region? No
does your region even use the meter for autocross? Yes
What's the cut-off in dB? 95
Is it the same for every class? Yes
Where do you measure from? 75 feet from the longest straight
How is the meter positioned? Perpendicular to the course on a tripod about 3' off the ground.
What's the required engine speed? No requirement
The statement still stands: I doubt he will ever run into a sound meter, since there is no specific rule for noise, region noise regulations vary widely, and having any rule let alone a meter is rare. At least three regions I run with use meters and enforce sound limits. (Devens National Tour has a sound requirement.)
does your region even use the meter for autocross? Yes
What's the cut-off in dB? 95
Is it the same for every class? Yes
Where do you measure from? 75 feet from the longest straight
How is the meter positioned? Perpendicular to the course on a tripod about 3' off the ground.
What's the required engine speed? No requirement
The statement still stands: I doubt he will ever run into a sound meter, since there is no specific rule for noise, region noise regulations vary widely, and having any rule let alone a meter is rare. At least three regions I run with use meters and enforce sound limits. (Devens National Tour has a sound requirement.)
Registered User
Joined: Oct 2000
Posts: 3,491
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From: Rochester, NY
Originally Posted by FormulaRedline,Feb 25 2008, 01:16 PM
The statement still stands: I doubt he will ever run into a sound meter, since there is no specific rule for noise, region noise regulations vary widely, and having any rule let alone a meter is rare.
While it's true that there are many sites that don't require sound control, I'll wager that you'll find more and more use, not less. Running at an airport (we do use the old Seneca Army Depot in Romulus, NY for local events as well as a ProSolo) tends to preclude the need but, since many (most?) sites are at least somewhat near housing, sound IS an issue.
Be happy that you haven't run into it. Of course, I don't mind not having those nasty-sounding Neons with straight pipes...
Joined: Jul 2003
Posts: 13,471
Likes: 35
From: Upstate NY
Originally Posted by FormulaRedline,Feb 25 2008, 04:53 PM
Interesting...so does that mean that one day you could pass the noise test and then next week fail because you are at a different RPM or throttle position at that position on the longest straight?
I've seen cars pass because they put a 90 degree elbow on the exhaust pointing away from the meter.
I have a friend with a formula car that has had to modify the intake because the incoming air was too loud.
It is not an exact science, but it does help to obtain and retain sites with neighbors.
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