MNZ Noise Regulations - and trying to figure them out.

[GaZBur]

Just installed a new-second hand can on the DR trying to eek out some more reluctant horses but was worried about the new noise regs. Here is what I found out as it will affect a lot of racers.

From MNZ site "Summary of Rule Changes Effective Immediately"

4-13 Noise Rule other than Road Racing
Noise Emmissions shall not exceed 96dBA; using the MNZ testing procedure and
approved equipment.
Where local body requirements or exemptions exists those requirements or
exemptions shall prevail. Proof of such requirements or exemptions shall be
made available to the Steward of the Meeting.

Machines will be tested at random or as required.

10-6-3a Noise Emmission Road Racing
All Road Race Events on Permanent Circuits (Teretonga, Levels, Ruapuna,
Manfeild, Taupo, Pukekohe, Hampton Downs as of this print) the noise limit is
95dBA.
All machines are to be effectively silenced so as not to exceed 95dBA “ride by”,
measured by the official meter mounted 30 meters from the track centre line, at
the position on the circuit nominated by the circuit owners/managers.
Machines registering readings consistently in excess of this limit will be brought
to the attention of the officials for action to be taken as follows:
Exceeding 95dBA but not exceeding 98dBA: On the first offence during the
meeting, the rider will be warned that this has occurred and instructed to rectify
the situation. For the second and subsequent infringements, the machine/rider
will be Black Flagged form the practice or race without further warning. If
circumstances do not allow the machine to be Black Flagged, the competitor will
be excluded from the results of that practice or race.
Exceeding 98dBA: The machine will be Black Flagged from the practice or race
without warning. If circumstances do not allow the machine to be Black Flagged,
the competitor will be excluded from the results of that practice or race.
At all Street Circuits machines must operate as per the conditions (if any) listed in
the local Councils resource consent for the event. Should these conditions
require special procedures and/or testing at the event, then these must be listed
in the Supplementary Regulations.
For special demonstation races/displays exemptions may be applied for, local

council resource consent forms must be attached.

Chapter 4 refers to Sanction of Meetings and Chapter 10 refers to Motorcycles Technical. This is in effect the opposite to what I had originaly thought - that we needed to be quieter at race circuits than other events but the measurements are actually taken differently. A 30meter away drive by at a circuit must make a god awful noise to register 95dBA whereas i believe the "MNZ" testing proceedure is 0.5 of a meter behind the exhaust at 45 degree angle. I don't have the exact description of MNZ testing proceedure but belive it depends on your bike, and think its measured at approx half its maximum horsepower revs.
If anyone knows the exact proceedure regs please post them for us. I have a loan of a noise meter and will be doing some testing of my own bike at Levels on Saturday as I would rather sort this myself than get told by the officials. Grab me or Mark if you want to check your bike there too. What is does appear though is that many aftermarket exhausts would be ok for circuits(10-6-3a) but not pass the MNZ Meetings (4-13) regs. So its possible you could be OK for Teretonga then excluded from Wyndham on the same set up.

OK, sorry if that sounds a bit whiney - in fact I am actually for reducing noise overall.

[lostinflyz]

haha not sure about the street stuff but the circuitb limit is alwyas measure at 30meters. My bikes been blowing 97.5 for the past few meets and they have told me to rectify (new cans come tomorrow all you moaners) but yea it does make a bit of a howl to registar that.however most bikes seem to measure low 90's at 30 meters so theyd all fail on the wof test like one.

as for wyndham (and other street races) there will be local restrictions on noise but if your ok at the sprints you should be fine for wyndham. At least i hope so. that reg 4-13 is for everything EXCEPT road racing. so should clear that out.

either way im all for increasing noise. hahahahaha.

FYI: i know at levels testing is conducted by standing in between the left hander after the hairpiin and the esses, basically looking directly up that wee straight part. If you stand on the spectators hill thats where they measure from. if your wanting to check actual race levels.

[GaZBur]

Initial rough tests last night for the new exhaust weren't encouraging. The reading bounced around a bit but when I could get a steady reading it was 96dBA. So for a safety margin I am going to have to pack the baffle more. To my untrained and slightly deaf ear, if this pipe is 96 then possibly half or more motards and race bikes will be well over and many of those expensive aftermarket pipes will fail the test.
I guess I will have to carry the huge heavy standard muffler to every meeting and jets to match untill I am officialy tested OK.

In case you are interested I got an email from Staintune that says when they do R & D "they do a stationary noise test at 1m distant from the outlet of the muffler...The test rev is calculated as half of peak horespower." So at least their ratings are actually measured for each bike the muffler is designed for. I don't know if this is an industry standard.

[lostinflyz]

yea sound testing is quite difficult. if your inside or theres ambient noise or a million other things itll change your reading. but it sounds like this is for a race bike and if so its only at 30 meters at full noise. i dont think last meet at timaru any motards were pulled up for noise. if its only registering 96 at half throttle at 1 meter it will easily pass the 30m test.

as for street circuits i dont think they reallycare about noise as i have heard of several people having removable baffles they leave in for the circuits and take out at street circuits.

[GaZBur]

yea sound testing is quite difficult...if its only registering 96 at half throttle at 1 meter it will easily pass the 30m test...

No I tested at 0.5 meter at 45 degree offset on an ashphalt pad. The exhaust is high mounted and I am aware that if you test near buildings, on concrete or have a low mounted exhaust the reading is likely to get secondary reflected noise. The bike is predominantly used for commuting but gets entered into every event its possible to run in. MiniTT, Road Hillclimbs, Road race, Street race, Gravel sprints, Gravel Hillclimbs, Motards at the kart track etc etc.
Every club in NZ have apparently now had thier noise tester and instructions delivered so will be testing. I know our club stewards and officals are good reasonable people and will try to sort this out without causing riders too much pain, but imagine getting to an event and finding a Hitler'esk type official with the ability to ban you. I would guess that all officials are the same as here, they do the job for the love of the sport after all but it would be wise not to piss off an official if you don't want to be randomly noise tested.