Exhaust Volume

[XXpl0Sive]

Has anyone had any experience with exhausts and their voloume?
Anyone been through an engineer's test where he measures the DB of the exhaust?

I can't get my car pass rego because I need to quieten the exhaust. Can someone give me an indication oh how loud 90db is?

What methods are there to quieten an exhaust? I cannot see a hole that I can bolt a silencer onto. Suggestions so far is to put a 1-1.5" gasket to restrict air flow.

The exhaust system atm is full 3" with the stock cat.

[Rowie]

SCREEEEEEAAAAAAAAAAMMMMM!!!!

thats bout it :D

anything over 80dB and your first reaction would be to cover your ears. 90dB is just over the point where it starts to effect hearing loss.

[XXpl0Sive]

Hahah rowie, really? that loud, the engineer told me stock cars produce around 85-87db, and I'd be really pushing it especially because it is 3", he said the air flow will cause it to fail - his instruments work by measuring the change in air flow or something :x

[Chi]

lol, i think my exhaust is past 90dbs, cos everytime i go thru a carpark most of teh alarms go off..

[XXpl0Sive]

Yeh most people's exhausts are over 90db - but its just because my car hasnt been registered before, it needs a blue slip and the exhaust gets tested.. let this be a lesson to those who purchase their cars from interstate...

****en stupid stupid rule I tell ya..

[Rowie]

as long as you dont have your ear sitting right next to your exhaust tip. But yeh, 90dB direct in the ear drum = hearing loss.

Theres no way you can get your hands on a dB meter ?

[Rowie]

put some chicken wire in the muffler for the blue slip.

[XXpl0Sive]

The engineer said it's the idle bassy tone that will make me fail..

See I have a dillema Rowie, I gotta pay $150 for this engineer, then $50 for the blue slip..OR go get a stock exhaust for the blue slip - any idea how much this will set me back (to remove and replace, then remove and replace again)?

If I could get a dB meter it would be great..

[McChook]

put some chicken wire in the muffler for the blue slip.

That works wonders. Actually, just 2 wires in a X in the exhaust tip do the same thing.

Shit, I didn't know 90dB was dangerous - I'd reckon I have my stereo above 95dB at most times.... and I attend a lt of concerts too...

[Rowie]

anything over 90dB will gradually make your ear drum hairs fold over. It doesnt make you deaf straight away, but with consistant high noise of over 90dB will effect your hearing :(

I wonder if you could go to a place like strathfeild car radio and see if they can measure it with a dB meter?

[XXpl0Sive]

Yeh, with most people's (aftermarket zorst) car being over 90db, I guess they don't hear it because they're in the cabin, all they hear is the bassy rumble..

[EuroAccord13]

I think how they test the dB is by placing the measuring device 1metre from the exhaust tip and measuring it at 3000rpm...

[Rowie]

I dont know if its any different. But in the State rally they test your exhaust dB, and hold the dB meter about 20cm from your exhaust tip and rev it to 6000RPM. There meters also test emission.

[VTEC16]

When i got my catback they (dalda exhaust- box hill-vic) tested the Db....cant remember what number i got...but it was below 90.

[XXpl0Sive]

What mods did you have on your car, VTEC16?

[cheebye]

hehe.. my last exhaust system on my wrx was measured at 125DB, w00t! :D

anyway, I heard dick smith sells db meters for like $80 or so, I think. might pay to go check it out

[4PERVZ]

I had my exhaust tested for an engineer certificate and it was 120db at 3500 revs! i would love to see wat it is whislt in vtec! i used a baffler to pass the test, then took it off! but from wat i have heard they r now illegal because it has to be welded on!

[VTEC16]

What mods did you have on your car, VTEC16?

just the 2.25" piping with a lukey "style" muffler.

[cheebye]

corect. they're getting smarter by the day. if ur muffler has a hole for the silencer, the only way they will pass it is by welding on the silencer asa permanent fix so u can't just put it on to test, pass, then put it back on and drive away.

[4PERVZ]

Most blue slip places dont really care if the baffler is permanet or not usually only exhaust places reject it!

[XXpl0Sive]

It really depends on which blue slip place you go. My advice, if you've got mods, go west.

I would of passed easily if I could be bothered driving, instead I took it to the closest place near me, and the mechanic had not done a small car before, he was a 4wd specialist, so he was doing my check "by the book"..

[[[d a n n y]]]

ben u need a pick slip?

i can get sum1 who will do it for ya..

[fueltank]

my car is under 90db Ben.
I think they rev it @ 1/2 or 2/3 of your car's peak power from factory.
Testing needs to be done in I think a 3m by 3m square with the db meter @ a 45 degree angle.

I got the PDF of ADR procedure on measuring exhaust noise somewhere.

[poid]

mate just get a 'rego muffler', will cost ya like $150 or so but that puny little restrictive thing will make sure you are under 90dB :)

Its basically tiny piping that bolts up to wherever your closest flange to the rear is, and a very restrictive muffler. Havent heard of any car fail with one on yet, and tons of them have been done by noe exhaust place i know.

[XXpl0Sive]

Thanks guys..

Really, fueltank, your car's under 90db? The engineer was giving me the impression that factory turbo cars were already on the verge of 90db.

Poid, I'm borrowing a stock exhaust and putting that on so hopefully this works out. Does anyone have jackstands or ramps I can borrow overnight? :) :)

Danny, it's a blue slip, I need to get the car in order before Thursday..thanks anyways!

[cheebye]

my car is under 90db Ben.
I think they rev it @ 1/2 or 2/3 of your car's peak power from factory.
Testing needs to be done in I think a 3m by 3m square with the db meter @ a 45 degree angle.

I got the PDF of ADR procedure on measuring exhaust noise somewhere.

I can't remember to be exact, but it's about 2/3's of your redline. For example, my wrx redline was 7000 and they tested it at about 4,500rpm.

[fueltank]

It's not from your redline, it's from your 'peak power'

Ben, I got jack stands.

[razztech]

hay boyz all ive done in the past is make a restrictor plate. what that is, is imagin a plate with lots of little holes in it. it maks a big differance. and with price to get a db test should only cost about 60-80$ [/quote]

[A'PEXi]

you can drill a little hole in for the silencer, done :D
add a resonator... change your exhaust....