Not only does the Lexus LFA deliver thoroughbred supercar performance, the sound it makes is every bit as thrilling. The acoustic performance of the V10 engine and exhaust system has been fine-tuned to create a unmistakeable 'soundtrack' that rises from a rumbling note at idle to a nape-tingling red-line wail.
The acoustic team studied the noise made by a Formula 1 car at maximum revs, then applied detailed design features to create an exhaust note for the Lexus LFA that is unlike any other car on the road, enhancing the sensation of speed and acceleration.
The main silencer is made of titanium and has a valve-actuated, dual-stage structure that channels the exhaust flow according to engine speed. Up to 3,000rpm, the exhaust valve stays closed, routing the flow through multiple chambers, creating an unobtrusive note. Above 3,000rpm the valve opens, allowing the exhaust to bypass these chambers and flow into a single resonance chamber, before exiting through the stacked trio of tailpipes.
The V10's induction system was also modified to complement the engine's acoustic qualities. The uniquely formed horizontally split resin surge tank - a unique design - mimics the acoustic chamber of wind and string instruments: up to 4,000rpm it emits the engine's primary firing frequency of 300Hz; this changes to 400 to 500Hz as the engine revs climb to 6,000rpm; and a peak is reached at 600Hz as the engine wails towards its 9,000rpm red line.
The air intake is made from a porous duct material to generate bass to mid-range tones. The Lexus LFA development team called this acoustic effect Resonated Complex Harmony.
The engine's induction and exhaust soundtrack are channelled into the Lexus LFA's cabin, so people on board can enjoy the experience as much as those on the outside. The main sound channel that pipes in the engine's induction notes runs from the surge tank into the cabin below the main dashboard panel.
Two further sound channels run to an opening in the upper cowl on top of the dashboard structure and a reflector panel low down at the front of the cabin. Together with the primary sound channel, these put the driver at the centre of the Lexus LFA team calls the 3D Surround Sound Concept.Published 11 December 2009