Toyspeed.org.nz Message Board

by **Leon** » Thu Jun 05, 2008 7:48 am

~SlideWays~ wrote:Hey Leon what did did you use to test them? I'd be keen to see what my trueno is like. I specifically went out to set it up to flow well but be quiet.

Come to Todd Park on Sunday, I'm trying to borrow the meter again for that day.

by **crispy'86** » Thu Jun 05, 2008 8:10 am

Again at this stage for the wof requirements if the inspector suspects the exhaust is significantly loud it's out. We hold the revs about halfway and give it a quick blip on the throttle. Had a wrx that came in a fortnight ago and he failed, he argued he had other work done on car so it was alright in his mind, apart from the fact that you could hear the turbo noise through his exhaust. Pretty much if it fails our subjective noise test we get them to go to Magoo mufflers where they can test it with their meter , if all good they come back with their printout even if it required work to quieten it down to a safe level. To give you a bad example of a quiet exhaust my trueno has 2 1/4 inch exhaust all the way through, the intermediate muffler is a cioby item, rear muffler was straight through but was quite tinny and loud, i put the inside of an exhaust about the same diameter inside the tailpipe exiting the muffler intentionally back to front, worked fine to quieten it. Then for shits and giggles got a muffler off workmate with 2 1/2 inch entry 4 inch exit, looks pretty rude but is quiet. Not the ideal way to do it for a good charecteristic for gas flow but does the trick. As for the 95db limit that again is for the testers to determine exactly what the limit is, if i remember correctly magoo has always tested for max of 95db on modified exhausts when this law first came in

by **CAMB01** » Fri Jun 06, 2008 2:35 am

Mine has 3" downpipe to 3" exhaust with a 12" coby resonator out to an RPS muffler. Doesnt sound that loud at all. Although its been a while since ive heard it lol

by **~SlideWays~** » Fri Jun 06, 2008 9:38 am

Leon, I might be able to come up but planning to spend most of the time working on my landcruiser, so will see how it goes.

Cam, any idea if resonators quiet down the noise or just change the note? I'm looking at options for my landcruiser and want it to be free flowing... without spending a fortune on a good silencer.

by **bluemaumau** » Fri Jun 06, 2008 11:42 am

really exhaust places shouldnt be allowed to make exhaust systems that are louder than 95db, unless you specifically state that the car is not for road use(i.e comp car, drag car etc etc

by **Silent Knight** » Fri Jun 06, 2008 12:13 pm

Sux to be me when the Soarer is back on the road then...

by **IH8TEC** » Fri Jun 06, 2008 1:17 pm

MR2SIK wrote:
IH8TEC wrote:my car is not legal, tested it today at work, 117db at 4k without silencer, 104db at abotu 3500 with silencer

88 at idle with silencer, without at idle is 102, inside the car at 3500 is 92db without the silencer. but i know for a fact when cruising it is quieter.

being around my car at 117db for more than 30sec causes permanent hearing damage, and at 88 after about 2-3hrs will cause permanent hearing damage

so from this, i'm going to try modify the silencer to quieten it down even more without restricting it too much.

Jeezuz Brendon, that puts my 107dB without Silencer to shame haha.
I just passed with a 97dB with the silencer in.

They still have the 2dB allowance for cars with the engine in the right place dont they?

yeah, the thing with my car is if your cruising, it's really quiet, with just revving it up on the spot it's pretty damn loud, half the noise is probably the car vibrating lots.

basically i can cruise at whatever speed drive normally with windows down, and talk to my passengers WITHOUT having to raise my voice.

by **bluemaumau** » Fri Jun 06, 2008 1:33 pm

does exhaust material i.e stainless or mild steel have any effect on noise?

OMG so shiny! · by **Dell'Orto** » Fri Jun 06, 2008 2:32 pm

it might affect the resonance (probably totally wrong) but wall thickness of the pipe does make a big difference.

by **Leon** » Fri Jun 06, 2008 5:39 pm

~SlideWays~ wrote:Leon, I might be able to come up but planning to spend most of the time working on my landcruiser, so will see how it goes.

Unfortunately I wasn't able to get the noise meter for Sunday anyway.

by **CAMB01** » Fri Jun 06, 2008 7:56 pm

~SlideWays~ wrote:Cam, any idea if resonators quiet down the noise or just change the note? I'm looking at options for my landcruiser and want it to be free flowing... without spending a fortune on a good silencer.

From my experience it just changes the note of the exhaust. Try putting like a turbo flow muffler in the exhaust system. Should quieten it down a bit without being too restrictive.

by **xsspeed** » Fri Jun 06, 2008 8:05 pm

I think you will find while a resonator does change the note, it will also offer a small amount of muffling, as would be expected due to the change in pipe.

As for pipe material, I beieve that it will alter the resonant frequency, of the vibration of the exhaust. Both material type, and material thickness would contribute to that.
However the resonant sound is due to the relatioship between the frequency of the source and the length of pipe.

I am not sure how much the vibration of the pipe will add to the loudness of the sound of an exhaust.

In fact a vibrating pipe may dissipate some of the sound wave energy, though this would not be a great feature to have on your car for obvious reasons.

by **escortman** » Fri Jun 06, 2008 8:22 pm

i hope puttin the coby quitens my car down a bit, im simialr to brendon crusing its fine, but if ur on the spot and give it a rev is loud, sounds awsome at idle tho hehe :twisted:

by **Chelles** » Sat Jun 07, 2008 3:56 pm

bluemaumau wrote:really exhaust places shouldnt be allowed to make exhaust systems that are louder than 95db, unless you specifically state that the car is not for road use(i.e comp car, drag car etc etc

There are limits for most race cars as well as a lot of venues have a limit they must comply with for their resource consents... can't assume you can have it as loud as you like these days.

I'm going to start to worry when they get touchy over induction noise! Mine out weighs the exhaust on the race car. (she is road legal)

Website · by **Emperor** » Sat Jun 07, 2008 4:00 pm

Yeah, my turbo spool, intake and bov together is way louder than my exhaust lol

by **Lloyd** » Sat Jun 07, 2008 6:06 pm

They can do you for intake etc as well, much like how they can for stereo stuff. Operating a vehicle in a manner likely to cause something something something

by **Zak** » Sat Jun 07, 2008 8:05 pm

HRT wrote:They can do you for intake etc as well, much like how they can for stereo stuff. Operating a vehicle in a manner likely to cause something something something

I don't like the sound of that :cry:

People that have heard my car will know why I'm conserned... :oops:

by **tsoob** » Sat Jun 07, 2008 8:18 pm

bluemaumau wrote:really exhaust places shouldnt be allowed to make exhaust systems that are louder than 95db, unless you specifically state that the car is not for road use(i.e comp car, drag car etc etc

according to a mate of mine that does exhausts it will be part of the law soon and the liability will be on the exhaust installer.... he is not impressed at all wont take much exhaust work anymore at all

Website · by Al » Sun Jun 08, 2008 10:55 am

HRT wrote:They can do you for intake etc as well, much like how they can for stereo stuff. Operating a vehicle in a manner likely to cause something something something

Operating a motor vehicle in an inconsiderate manner. $600. Been there, been threatened with that.....and it was 8 years ago.

by **Paulio** » Thu Jun 12, 2008 9:06 am

so kerm3t has been hit by the 95db exhaust noise limit..

has anyone experienced the change between 105db and 94db??

honestly, it'll turn your car from sex to homo in the time that pitstop takes to install a new muffler.

Toyspeed.org.nz Message Board

So aparently the exhaust noise laws have chenged again?

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