Chp Exhaust Decibel Testing For You Guys
05-20-2005, 01:43 PM
#1
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Thread Starter
Join Date: Apr 2004
Location: Nor CAL
Posts: 171
For some of you who may live in California CHP has been on the warpath for modified exhaust. I work for the BAR, “don’t stone me” Today I was doing a sound decibel test on a 240sx that could have easily been avoided. So, here you go. SAE J1169 sound test specifications. Top secret yo! 
Maximum decibel ratting 95 + or - 2.
FD Test RPM = 4875
Rx8 test RPM = 5400
240Sx Test RPM= 4200
Tests are performed 20 inches away from mufflers tip at a 45 deg. Angle.
The sound testers can be found at radio shake I think. Just a nice way to test to see if that silencer is working up to Highway patrols spec. If anyone wants any other cars testing speed just let me know.
-Tyler
Maximum decibel ratting 95 + or - 2.
FD Test RPM = 4875
Rx8 test RPM = 5400
240Sx Test RPM= 4200
Tests are performed 20 inches away from mufflers tip at a 45 deg. Angle.
The sound testers can be found at radio shake I think. Just a nice way to test to see if that silencer is working up to Highway patrols spec. If anyone wants any other cars testing speed just let me know.
-Tyler
05-20-2005, 03:07 PM
#8
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Join Date: Jan 2003
Location: London, Ontario
Posts: 2,871
I'll have to use the db meter at work once I get the car going. might be illegal for all the events I want to enter!
Pretty stupid, all competitive events publish an allowable limit and the method of testing, but the highway traffic act is the definition of vague.
Pretty stupid, all competitive events publish an allowable limit and the method of testing, but the highway traffic act is the definition of vague.
05-20-2005, 03:30 PM
#9
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Thread Starter
Join Date: Apr 2004
Location: Nor CAL
Posts: 171
yup, its an easy reson to pull someone over. Talking to a few cops about it say. "If the car is really loud and has an aftermarket muffler the car might also have, fuel pressure regulater, intake, headers etc. It makes a good reson to pop your hood. The CHP is very vague about it because they dont understand it. Some cop around where i live keeps giving tickets to kids for there OEM mass air flow sensor. must be some kind of high tech japan part...
05-20-2005, 03:33 PM
#10
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Join Date: Jan 2003
Location: London, Ontario
Posts: 2,871
That's nothing, at least California has a measurement of what is "too loud" so you can argue your case. Everyone else has the cops word, no measurement, no comparison, busses, trucks and Harleys don't get hassled despite being MUCH louder in some cases.