Interested in how loud your bike is?

[Gremlin]

Well, I am. Some of you may have heard of Racefit... and I happen to have a growler fitted. According to the new regs that have come in, if the exhaust system has a manual control on it (ie, removable baffle) then it has to be tested in all states (meh... the loudest one). So really... the growler hasn't a shit show of passing... but it would be interesting to see just how high it can score :whistle:

Anyway... I'm wondering if others are interested, as I am prepared to go get a nice new shiny toy (downside of being in IT), and test others as well, for a small fee (probably $5-$10 at this stage) but want to know if others around Auckland are actually interested, coz it ain't cheap, as regular calibration is required (thats the more expensive part).

It won't be able to be provided as evidence, as filling out all that paperwork just ain't worth it, but it will provide you an idea of how bad/good it is, without risking the wof, or being pulled over in the middle of nowhere, and the cop surprises you with it being ordered off the road.

Aim is just to help people find out a reasonably accurate figure, without costing the earth, or wrapped in paperwork etc. It probably wouldn't be on a per test basis, just tests on the day (If I can source a suitable site, I will probably organise events for bunches of people to be done in one hit). Use the poll, feel free to provide additional comments...

[James Deuce]

Problem is it needs to be a ride by test not a static and it needs to be conducted outdoors as well. This needs some pretty clever and expensive testing gear.

Static testing inside a building is going to give bogus readings. Bikes make a huge amount of noise from the engine, transmission and drive components as well, and the exhaust is only the easiest noise maker to point at.

[boomer]

i took my bike to colemans earlier in the week and asked if my Growler would pass a WOF, which is due. He revved it hard and laughed.

I'll be fitting teh stock pipe on to get my ticket...and then we'll growl again.

[vifferman]

Problem is it needs to be a ride by test not a static and it needs to be conducted outdoors as well.
Does it? :confused:
I thought it was static test, conducted with the measuring device at 45 degrees to the pipe, at a distance of 1 metre, etc etc.

I know how loud my pipe is - the Staintune website lists the values somewhere (without restrictor = FAIL, with = PASS). The only tricky part is the restrictor - it's removable. There's no way I'm sticking a standard muffler back on, so if/when it fails I'll just get the quieter of the two restrictors welded in.

[imdying]

Problem is it needs to be a ride by test not a static and it needs to be conducted outdoors as well. This needs some pretty clever and expensive testing gear.What? The testing done by the Low Volume Vehicle Certifiers (i.e. the testing that needs to be done if you fail the discretionary test by the WOF tester) is neither a ride by test, nor is it done by expensive testing gear.

[James Deuce]

Does it? :confused:
I thought it was static test, conducted with the measuring device at 45 degrees to the pipe, at a distance of 1 metre, etc etc.

I know how loud my pipe is - the Staintune website lists the values somewhere (without restrictor = FAIL, with = PASS). The only tricky part is the restrictor - it's removable. There's no way I'm sticking a standard muffler back on, so if/when it fails I'll just get the quieter of the two restrictors welded in.
Yes it does and you are dead right. That's why the test is bogus.

[James Deuce]

What? The testing done by the Low Volume Vehicle Certifiers (i.e. the testing that needs to be done if you fail the discretionary test by the WOF tester) is neither a ride by test, nor is it done by expensive testing gear.
I'm not suggesting that it is is, I'm telling you how it is done in countries who know what the are doing, specifically in the area of certifying new models as they introduced.

A static test is actually a total load of rubbish.

[jrandom]

I am prepared to go get a nice new shiny toy (downside of being in IT), and test others as well, for a small fee (probably $5-$10 at this stage) but want to know if others around Auckland are actually interested, coz it ain't cheap, as regular calibration is required (thats the more expensive part).

Huh?

You can buy an SPL meter at Dickheads for $130 (http://www.dse.co.nz/cgi-bin/dse.storefront/488f9a6803be2588273fc0a87f3b0719/Product/View/Q1362). Accurate to +/- 2dB, which should be good enough for this purpose, no?

And what's this 'regular calibration' stuff? You're only using this to get indicative measurements, right?

Regular calibration of test equipment is only really done so that results can be proven to be accurate when cold hard cash is on the line. (Speeding tickets based on radar readings, contract manufacturer quality assurance levels, etc.)

Solid-state measurement electronics almost never actually need adjusting.

[Gremlin]

Solid-state measurement electronics almost never actually need adjusting.
Well, the real test requires the device is calibrated before and after every test (and must remain within 0.5db accurate iirc), and while I am not going to be quite that pedantic, I figure it makes sense to be reasonably close to that. However, I have no idea just how quickly its going to be out, so figure better safe than sorry. Sounds like you would have a better idea of how long it would remain accurate than me.

The test would be static, along the same requirements of the lvvta/ltsa, measure at 500mm on the 45 degree, no less than 200mm off the ground. Re the sound of the engine, I believe this has been compensated for in the regs, with bikes having a higher limit than cars. There is a provision in the regs to allow an extra 4db (section 2.9(2)) for exhaust outlets positioned within 1.5m of the engine, however, this specifically excludes motorcycles.

Re the site, it has to be predominantly flat, diameter of at least 6m, concrete or tar, not enclosed, with no sound absorbing materials or basically any other obstructions in the area. There are also rules around how loud the background noise can be, spikes in background noise etc etc.

[jrandom]

Well, the real test requires the device is calibrated before and after every test (and must remain within 0.5db accurate iirc), and while I am not going to be quite that pedantic, I figure it makes sense to be reasonably close to that.

Fo' true.

You might find that getting within 0.5dB SPL accuracy starts to enter the diminishing-returns part of the cost curve, though.

I'd just use the cheapie 2dB-accuracy meter to get an indicative reading. It's just about figuring out whether you're in any danger of failing the official test, right?


Sounds like you would have a better idea of how long it would remain accurate than me.

I worked on software driving test gear for noise-cancelling headphones for a couple of years, back in the day.

Vehicle noise testing is bigger, noisier and messier, but I'd imagine that the principles and the basic equipment involved are much of a muchness.

[Gremlin]

You might find that getting within 0.5dB SPL accuracy starts to enter the diminishing-returns part of the cost curve, though.

I'd just use the cheapie 2dB-accuracy meter to get an indicative reading. It's just about figuring out whether you're in any danger of failing the official test, right?
Re the device, no experience, but I would imagine it shouldn't go too inaccurate too quickly (after all, the real guys are not using equipment much different to what I would have), and I suspect a few people will probably be marginal, so a bit of accuracy wouldn't hurt. However, bearing in mind the device is 1.5db accurate, not much more expensive than the DSE one, its the calibration unit that increases the cost. (if you're going to do it, may as well do it right)

Re the official tests, it would appear that what I would like to do would be similar to what the wof testers would do (unknown if they would actually have the equipment though, and them being them, they can just claim its too loud), and that if you do fail, you need to go for a full noise test (this one is termed the "Quick Noise Test") which is more expensive, $150-$200 I have been reading, and obviously the number of people that can do that is much more restricted.

Yes, ultimately, its about giving people a clear idea of where they stand, without the risk of not getting a wof etc, but to be worth it, it should be as similar as reasonably possible (otherwise, whats the point).

Oh, a point for all of you considering swapping the pipe. There are pieces of the regs that detail when certifying it, that detailed notes must be made on the system, components, bike, and at least one clear pic of the exhaust. How this will all be enforced, don't know... but the rules are there.

[imdying]

I'm not suggesting that it is is, I'm telling you how it is done in countries who know what the are doing, specifically in the area of certifying new models as they introduced.

A static test is actually a total load of rubbish.

I'll bear that in mind if I need a warrant on my bike from another country :rolleyes:

[saul]

Yep my girlz bike went to a storming 105 or 107 dba:clap: So no pass warrent.

What a laugh as my pipe is actually not very loud at all, but the pitch is quite high (cause its a girlz bike).

There you go then:clap:

No real worries got it sorted till next year:rolleyes:

[jrandom]

my pipe is actually not very loud at all, but the pitch is quite high

That's interesting.

Does anyone know whether the exhaust noise test uses 'C' weighted dB SPL?

[Gremlin]

Does anyone know whether the exhaust noise test uses 'C' weighted dB SPL?
A weighted, according to the regs

[jrandom]

A weighted, according to the regs

You'd bloody hope so aye.

'A' weighting is just a flat measurement of sound pressure energy, whereas 'C' weighting is an out-of-date oversimplified psychoacoustic model which weights some frequencies over others in the result.

[vifferman]

That's why the test is bogus.
It's also bogus because although some allowances are made for engine noise being higher on bikes, it is essentially and ostensibly/supposedly a test of only how much noise comes out of the zorst. I have a feeling that even though my muffler will pass the test, my bike may fail, as the cake mixaahh!! makes so much noise itself. Lucky I don't have a dry clutch (although I do have some clutch noises, sundry engine parts rattles, oil pump rattle, etc.)

If/when my bike gets tested, I may have to either try to muffle the engine or pack the zorst with sound-deadening materials (like hamsters, 10-day old porridge, or politicians....)

[saul]

That's interesting.

Does anyone know whether the exhaust noise test uses 'C' weighted dB SPL?


Yeh I should have had a look at his settings.

I would think that he would have just been on "A" - slow cause it was a static test and SPL but I didn't look.

Talked about the system being moderated heavily at the moment because "they" wanted to see results. Lol wonder what that means:gob:

[jrandom]

I would think that he would have just been on "A"

A lot of audio test gear, particularly stuff that's not cutting-edge new shit and was originally designed for PA type purposes, defaults to 'C' mode and needs some twiddling by the operator to get it reporting results in 'A' mode.

If it's being driven by a numbnuts spanner jockey I wouldn't be surprised if it's being left in 'C' mode by mistake, which would explain your high reading.

[Gremlin]

Yeh I should have had a look at his settings.
Yep, for extra info, it has to be A weighted, meter set to fast response (there are several modes), three measurements must be taken to one decimal point, which are then averaged and conventionally rounded to a whole number.

Spikes during testing mean the test must be excluded, and another taken, and then you have the site considerations to also take into account along with positioning of equipment.

I wonder if I could beat your score with my baffle still in... I just need the equipment :rolleyes:

[pritch]

I know how loud my pipe is - the Staintune website lists the values somewhere

So too with Arrows.

When I discussed this "subjective" noise testing aspect with the WoF tester I use he told me that it's largely an attitude thing. Yours and his.

I took his comments to mean that if neither the noise nor the rider is obnoxious - no problem. Variation from that on either count? Problem!!!

Makes sense, they are human too. (Well most are :-)

[vifferman]

So too with Arrows.
Mmmmmm.... Arrows. :niceone:



Makes sense, they are human too. (Well most are :-)
Welllll.... I'd say a fair proportion (at least many of those that work for VTNZ or VINZ or whatever it is) seem to fall into the "subhuman" (i.e., Petty Bureaucrat with a Grudge and Permanent PMS) category.

[Toaster]

Keep in mind fooling the WOF tester is only a partial solution. Once the exhaust is back to its normal loud self you may have it green stickered by the police for being too loud - then your so called WOF is as good as pigs weez in a yard glass.

[AlBundy]

Just a question...

Isn't dB exponential. Isn't 2dB at lower levels totally different to 2dB at higher levels...

So, it's all well saying it's 2dB out but it's make a huge difference when borderline high...

[mashman]

One thing that hasn't been discussed, not that i've read anyway, is that a bike will make more noise (pitch or sound???) the higher in the rev range it goes. If they are going testing for WOF pass, does each bike have to be under a certain DB level at a certain point in the rev range and under certain test conditions. I have open Akras, not the loudest, but they're pretty noisy. When the guy across the road from me starts his Harley it pales mine into insignificance. How can they justify how noisy your bike is?

[Gremlin]

If they are going testing for WOF pass, does each bike have to be under a certain DB level at a certain point in the rev range and under certain test conditions.
Depends on the bike. There are set rev limits for certain machines, and it varies according to 2-stroke or 4-stroke, how many cylinders, valves per cylinder etc.

Ie, my zx10 is a 4 stroke, 4 cylinder, which means it will be tested at 4500rpm.