Worth making a noise about

[Grant Schou]

Worth making a noise about

By Alistair Davidson

If you're into performance cars but don't class yourself as a 'boy
racer', watch out.

As part of an ongoing * and needed * campaign to stamp out illegal
street racing, the LTSA quietly eased another law into effect on May 2,
2003, as part of the Land Transport Act 1998.

Unfortunately it's a case of the LTSA using a sledgehammer to crack a
walnut, or in this case, using a blanket approach to silence noisy
exhausts.

It is now illegal to operate a motor vehicle if, according to the LTSA
Infosheet 2.04, "the noise output is noticeably and significantly higher
than should be expected for the vehicle".

The LTSA goes on to say that "When the vehicle leaves the manufacturing
plant, it will have been fitted with an effective exhaust system and
silencer. This is your (WOF issuers, police) point of reference for the
performance of any replacement exhaust systems.

"A modified exhaust system should not make the vehicle louder than it
would have been when the vehicle was manufactured with its original
system."

Don't make the mistake that this would only be enforced if you were
pulled over when caught street racing, or driving in any other illegal
or dangerous fashion. This is a warrant of fitness requirement, and will
be evaluated at your car's next WOF check.

Tony Johnson of the Low Volume Vehicle Technical Association (LVTTA)
believes that this law has come about from police and political pressure
to clamp down on boy racers.

"Noise used to be a vehicle operational issue, which would have been
enforced by the police," says Johnson. "Suddenly it's a vehicle
equipment issue, so it's part of the WOF process. The fallout from this
could be horrendous."

Low volume vehicle certification ensures that modified vehicles are
safe, and that critical areas of the modifications are carried out by
approved engineers.

Because exhaust noise was an operational issue, it didn't fall under the
certification umbrella.

Therefore, every vehicle with an exhaust that's 'noticeably' louder than
factory original is now illegal.

Thanks to the boy racer crackdown, most big-bore late model Commodores
are now unwarrantable.

This writer has a modified and fully certified 1936 Ford hot rod, with a
5.0-litre Ford V8 and five-speed manual gearbox. Until May 2 it was
legal, but now it isn't because the car's expensive and efficient
exhaust has to be no louder than when the car (not the engine) left the
factory, back in 1936.

Which begs the question, who is an authority on how a standard
production 1936 Ford sounded when it left the showroom almost 70 years
ago?

A young police officer who mistakenly pulls me over thinking I was
street racing certainly wouldn't have any idea.

Herein lies the problem. The noise test guidelines, which are part of
Infosheet 2.04, don't rely on a decibel meter.

The WOF issuer or police officer is required to rev the engine to
halfway through the engine's rev range, hold the engine at that speed
for five seconds, the reduce to idle. This is followed by "three or four
short and sharp speed increases, from idle to test speed".

Sadly this test relies of the quality of the official's hearing, and
doesn't take into account the surface on which the test is carried out,
the surroundings (e.g. outdoors, or in a tin-clad workshop).

It also relies too heavily on a police officer's judgement. A speed
infringement notice is issued with evidential support such as a photo,
radar reading or a police car speedo. Equipment has to be calibrated and
tested.

There is no technical equipment required for the noise test, either at
warrant time or during a traffic stop.

If your car is deemed to be too noisy while driving it will be 'green
stickered', or rejected at warrant time. Once corrected you are not
permitted to take it to one of the 3200 independent warrant issuers for
a re-check. This must be done by a transport Service Delivery (TCD)
Agent (AA, On Road NZ, Vehicle Inspection NZ or Vehicle Testing NZ).

"It's done, and the LVVTA can't influence that decision," says Johnson,
who was given one working day in late April to make a submission prior
to the regulation being passed into law. "Huge public pressure is the
only way it could be changed, and if that doesn't work it may fall back
onto the LVVTA.

"We're currently working towards a solution, but the whole issue is
riddled with holes.

"After all, how do you certify an invisible modification?"

[Phil McArthur]

"A modified exhaust system should not make the vehicle louder than it
would have been when the vehicle was manufactured with its original
system."

-Presumably this means that an EVO lancer or WRX Impreza, or Commodore for
that matter, will be OK with its original, factory fitted, albeit loud
exhaust? This seems to refer to replacement systems only.

[lou Girardin]

A perfect test case, the LTSA will have to prove that it's noisier than the
original vehicle. Impossible!
Bear in mind though, that there is also an absolute decibel limit of 81db.
Although many unmodified vehicles exceed this already.