Monday 5th December 2005

Winter makes trackdays noisier

So says exhaust system specialist

---

Too noisy?

Track day drivers whose cars passed noise tests with flying colours in the summer months could find the car is noisier on winter race circuit thrashes. And a company that sells exhaust systems reckons it knows why.

The same cold air that gives track day enthusiasts a few extra bhp and a little more buzz is also causing more sound limit infringements -- and unfortunately a few more sharp exits from carefully noise-monitored race tracks.

"There's a simple explanation, but that doesn't make the cars any quieter: noise travels further and faster in cold air, so the noise monitoring equipment inevitably picks up higher readings even though the cars are not actually any closer or any noisier," said specialist exhaust manufacturer BTB's boss, Joe Ellis.

"The noise problem has intensified after several landmark rulings in favour of local councils forced the circuit owners to adopt continuous trackside noise monitoring in order to comply with planning requirements. The problem is also compounded by many car users' belief that more noise means more power - that's not the case at track day level, or even for some race cars", said Ellis.

"We've already a great deal of experience in terms of supplying power-efficient silencers to leading F3 and BTCC teams, and this has enabled them to test at circuits normally made unavailable to them because of strict noise regulations. There's a bonus for track day enthusiasts as a result: by applying the same exhaust technology it is possible for them to enjoy their highly modified cars' full potential whilst still satisfying circuit noise requirements, a matter which is coming more and more to the fore.

"Furthermore, BTB can offer a free noise-testing service to all members of recognised track day clubs so that they can establish their cars' noise levels before wasting their time and money taking a non-compliant car to a noise restricted circuit. If there is a potential problem, then BTB can accurately advise and quote for a suitable system that solves their problem."

BTB said that it "develops and manufacturers exhaust manifolds and systems in a variety of materials for a number of markets. As well as OE development for car manufacturers, BTB manufacturers exhaust systems for a number of motor racing teams at various levels in the sport, plus limited production runs for specialist aftermarket distributors and bespoke systems to address one-off requirements."

Might be worth a look...

• www.btbexhausts.co.uk

[Avocet]

Absolutely true! Major car manufacturers often do their noise type approval testing in hot places like Spain for exactly this reason. Someone once told me that every 10 degrees C was worth an extra 1dB at the noise meter although given that the noise scale isn't linear and the temp scale is, I doubt that is strictly true, but the general principle is!

[sdd]

Sounds about right, the track-club Radical SR3 has been quite happly going round Bedford all year until about two weeks ago when it got thrown off for being too loud, an above average number of other cars suffered the same fate. Fortunately we've now resolved it with an even quieter exhaust.

Just the Caterham CSR 260 to deal with now before the RMA day on the 17th.........

Stephen

www.track-club.com

[900T-R]

On a related note, a tale from a Saab board on the Classic 900 turbo:


"A quick note, a former colleague of mine who worked on Type Approval (as I did) was responsible for the type approval testing in respect of noise for this car. If I remember correctly, the first time they tested the car (In Sweden) it failed. The car was then tested in his country (Holland) as it was warmer there and the warmer the ambient temperature the less well noise is transmitted. It failed again. The (same) car was finally shipped to Spain where it was very warm and it passed.



1) EEC regs stated that the car must be tested in the EU but laid down little data about testing conditions

2) Noise limits have since been reduced several times, and if the car were current it would not pass

3) IIRC the car was notionally illegal in Switzerland in standard form!"

Makes one wonder how the heck TVR manage to pass the noise tests for their cars every time (although I suspect SVA regulations may be a bit laxer in that respect than full EU Type Approval stuff)... but thank God they do!