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Is there an art to making noise?
Is there an art to making noise? RML’s engineers believe so. The new Short Wheelbase’s production prototype, Car Zero, will be completed in the coming weeks and the development team will finally be able to hear the full majesty of its sonorous V12’s exhaust note for the first time.
“The target was to emulate the exhaust sound of a classic V12 road-racer,” said Adnan Rahman, the Short Wheelbase’s Powertrain Design Engineer. “That meant effectively starting from scratch with the donor car’s exhaust, from its catalytic converter back to the chrome-plated quad tailpipes that are such an important feature of this car’s design.”
To establish a base-line, Adnan and his team made recordings of the donor car’s 5.5-litre Ferrari V12 from inside and outside the car at various speeds and loads, from idle to full-throttle acceleration. The engine was also put on a dynamometer, and data from both tests was built into a computer-simulated model that could be adapted to suit the new noise requirements of the Short Wheelbase.
The donor car’s chassis was also modified to accept the new exhaust system, including an all-new, double-chamber rear silencer box, where the stainless-steel pipes from each cylinder bank join, and beautifully crafted twin-tailpipes emerge from each side.
“It was essential that two other targets were met, too,” said Adnan: “Making sure that the engine’s performance was retained, and also that we worked within the boundaries of current noise regulations. In fact, while exhaust back-pressure has not been impacted at all, in some areas we’ve actually improved it, so we’re right on track
with our performance predictions for the Short Wheelbase.”
With Car Zero’s bespoke exhaust system almost ready for installation, is Adnan concerned that it may not sound quite as good as he’d hoped? “Not at all. RML has plenty of experience designing systems like this, so the fundamentals will be right first time. But we always build in some adjustability so that we can finesse the exhaust’s acoustics during real-world testing, which will start next month.”
More news will follow through the final stages of Car Zero’s build, but in the meantime please visit https://rmlgroup.com/news to see all previous releases.