It could have been a crime - but no offence was committed or caused as a legend took to Goodwood's race circuit.

Silencing one of the most charismatic sounds in motor sport - Audi UK's ex-works S1 Quattro, one of only two surviving in the world - has become the latest challenge for Daventry-based BTB Exhausts, which specialises in race and trackday systems and silencers.

"It would have been criminal to kill the sound of that car, but we're delighted with the outcome," said Joe Ellis, Managing Director of BTB.

Audi UK's ex-works S1 Quattro was to be demonstrated to journalists by rally legend Hannu Mikkola at the UK launch of the new RS4.

The venue was Goodwood race circuit, one of the most rigorously noise-monitored circuits in the country. It was vital to avoid stangling the fearsome 600bhp output of the priceless car's engine, and BTB managed to keep it all intact despite reducing the noise below the 98dB limit.

"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. We applied the same principles to the Quattro."

BTB 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.

Further information  www.btbexhausts.co.uk  built by Racecar