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

 

Top secret except that got shipped in my HKS exhaust box?



Is that loaded or in neutral?

 

Oh, well it was a joke...and I have every car and every year..Yes it is in neutral.

 

I put my ear up to the tailpipe and had someone crank it up.



eh?

 

So, the sound meter is on the ground? Pointing up at a 45 degree angle?

 

no they have a small tri pod. they sit about 3 inches off the ground and sit level.

the angle is if you were looking at the car from above.

 

not top secret anymore





ITS ON THE INTARNET !

 

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.

 

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...

 

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.