QLD exhaust decibel testing method?

Simmo · 25-01-2006, 04:43 PM

a mate of mine works at an electronics shop and has agreed to let me decibel test my new exhaust with their awesome gear. what i would like to know is the proper police testing methods so i can get it right and see if i need to make it legal. i know there's a certain distance and angle it has to be on, not just shove the mic in the pipe.

347Stroker · 25-01-2006, 04:45 PM

Bring it around to my place,

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Get in car and rev the sh1t out of it for 3 minutes
If the bible bashers next door dont turn on their lights, it can be louder....

GreenMachine · 25-01-2006, 04:49 PM

rpm equal to 2/3rds of where peak power is made (i.e. if peak power is at 15,000rpm (yours is. trust me.), then it's tested at 10,000rpm). The mic is 6 feet from the tip of the pipe , on an angle away from the car (i.e. if the pipe is on the RHS, it's 6 feet diagonally to the right of the pipe).

90% sure that's correct.

Simmo · 25-01-2006, 04:57 PM

sounds like a plan. anyone actually know the legal limit on cars? 88 and 90db ring bells in my head. never had to worry about all this with the super-mega-50 mufflers and a blocked cat system that was on there.

Racecraft · 25-01-2006, 05:06 PM

the guys were testing some new gear at Zillmere mainroads one day and I asked them what it was.. It was the new tester... It is a foot by foot triangle on a foot tall tripod with the mic on it.. hard to explain but it is a foot away from the tail-pipe on a 45 degree angle and a foot off the ground

EvilChief · 26-01-2006, 05:44 AM

45degree angle and 1m away toards the opposite end of the car from where the exhaust is located (ie exhaust is on RHS, device i head at 45 degree horizontal and 1m away and same distance off ground as exhaust pipe towards LHS). RPM = 2/3 of max rpm, ie max rpm at 6000rpm = tested at 4000

thats how the cops showed me when i asked them to explain it to me

jabba · 26-01-2006, 07:41 AM

Quote:

Originally Posted by GreenMachine

rpm equal to 2/3rds of where peak power is made (i.e. if peak power is at 15,000rpm (yours is. trust me.), then it's tested at 10,000rpm). The mic is 6 feet from the tip of the pipe , on an angle away from the car (i.e. if the pipe is on the RHS, it's 6 feet diagonally to the right of the pipe).

90% sure that's correct.

90% correct, YES..... the rpm you need to be tested at is 4000 rpm, regardless of your rev limit (unless of course you car dose not rev to 4000)
mic is 6 ft to the side of your car at a 20 deg angle back. (i.e. if the pipe is on the RHS, it's 6 feet diagonally to the right of the pipe angled back 20 deg). if you have a pipe coming out on both side of your car (like new GT) you will have to conduct the test twice. Once on each side of your car....

An interesting note. When testing you do not take into account the back off gurgle you exhaust make when you get of the peddle.....

Gammaboy · 26-01-2006, 10:00 AM

Quote:

Originally Posted by Racecraft

the guys were testing some new gear at Zillmere mainroads one day and I asked them what it was.. It was the new tester... It is a foot by foot triangle on a foot tall tripod with the mic on it.. hard to explain but it is a foot away from the tail-pipe on a 45 degree angle and a foot off the ground

Well, if anyone gets pinged using that equipment, I'm pretty sure its able to be fought, from memory its too close to the pipe and will cause inaccurate readings due to near field effects (Been a while since i did noise and vibration type accoustics, but recall that theres a minimum distance for measuring based on the lowest frequencies expected to be found). This is from an engineering standpoint, not department of transport bullИИИИ rules.

Quote:

Originally Posted by jabba

90% correct, YES..... the rpm you need to be tested at is 4000 rpm, regardless of your rev limit (unless of course you car dose not rev to 4000)
mic is 6 ft to the side of your car at a 20 deg angle back. (i.e. if the pipe is on the RHS, it's 6 feet diagonally to the right of the pipe angled back 20 deg). if you have a pipe coming out on both side of your car (like new GT) you will have to conduct the test twice. Once on each side of your car....

An interesting note. When testing you do not take into account the back off gurgle you exhaust make when you get of the peddle.....

Sweet. this means that my RG is barely above idle if/when it gets measured.
Anyone 100% on the sound limits? bikes 96db(a)? Pre 90 something cars 92db(a)? newer 88db(a)?