Lamborghini has revealed full details of its all-new V12 engine, set to make its debut in next year's Murciélago replacement. Here, Autocar takes an in depth look at the new 6.5-litre unit, as well as the firm's new single-clutch automated manual gearbox.
The engineLamborghini’s R&D team was given just two criteria for the new motor, codenamed L539 and designed from a blank sheet of paper: it had to be a V12 and have a 60-degree bank.
In the end the team ended up with the old motor’s 6.5-litre capacity, but 59bhp more, at 691bhp. There’s more torque, too - a peak of 509lb ft - and it’s available 500rpm further down the rev range, at 5500rpm.
The bore increases, from 88mm to 95mm, but the stroke is down from 89mm to 76.4mm; the compression ratio is 11.8:1, compared with the old unit’s 11:1. There’s also a useful reduction in weight, from 253kg to 235kg, and the dry sump height is just 120mm, 75mm lower than the old motor’s. “This makes a big difference in the centre of gravity,” chief engineer Maurizio Reggiani says.
Features to improve the motor’s efficiency include switchable water circuits to hasten warm-up, and a total of eight scavenging pumps that reduce pressure and scavenging losses by around 50 per cent.
There’s no direct injection, though - for now, at least. “We looked at it,” Reggiani revealed, “but there are issues with back pressure [in the exhaust system] and how you manage that while still achieving maximum power. Multi-point injection is a simple solution that avoids an additional device to reduce particulates, so we’ve gone with that. But DI is something we could look at again in the future.”
The gearboxHaving ruled out a dual-clutch unit, Lambo has gone with another single-clutch automated manual for the next Murciélago. “It’s the most emotional system to use,” said CEO Stephan Winkelmann, who has called the new unit - developed in conjunction with Graziano - “a sequential race gearbox in a roadgoing car”.
The new gearbox (called ISR, for Independent Shifting Rods) is a seven-speed, 70kg unit with a twin-plate, 235mm clutch. It uses four shifting rods to run the shift process “virtually in parallel”; times fall to as little as 50ms, around 40 per cent faster than with the Gallardo’s e-gear system.
The gearbox will run in three modes: Strada, which will offer a fully automatic shift if desired, the more focused Sport and the extreme Corsa, which will also include launch control.
The differential set-up includes a computer-controlled unit at the front, instead of the old viscous coupling, a Haldex4-based centre diff and a rear unit that’s integrated into the casting of the engine.