Diesel power for sporty Peugeot
Diesel engines and sleek, stylish, Grand Touring coupes traditionally don’t go together. A quad cam V6, a turbocharged four-cylinder, a V8 or a V12 – all petrol-powered, of course – are the more usual powerplants for high-end sports-oriented cars. But Peugeot is out to challenge that perception. It has already embarked on a programme to win the 24-hour sports car race at Le Mans with a diesel-engined protoype – Audi is out to do the same and stole something of a march by winning the Sebring 12 hours in Florida this month with the R10 diesel.
And Peugeot is also taking diesel into the roadgoing luxury coupe market with a diesel V6-engined version of its ultra-chic 407 Coupe. The diesel is one of three 407 Coupe variants Peugeot is selling in New Zealand – the other two, with a choice of six-speed manual or six-speed automatic gearboxes, run petrol V6 motors.
The petrol version of the new Coupe with six-speed manual gearbox has a recommended retail price of $71,900: with the six-speed automatic transmission it costs $73,990. The HDi diesel, available only with the new six-speed automatic, is priced at $75,990.
The Coupe’s steeply-raked windscreen creates a low roofline that flows back into the boot with its integral spoiler. At the rear, the lower panel creates an unmistakeable visual impact. The grille is the wide-mouthed, Ferrari-like opening, familiar on the 407 sedan
and SW. Inside, the two-door Coupe reflects a great tradition of GT touring cars with four individual bucket seats, a classic instrument panel, real aluminium trim detail and leather upholstery.
Compared to other 407 models, the Coupe’s driving position has been lowered by 20mm and is mounted further back. Though it’s built on the same platform as other 407s, the Coupe is 139mm longer than a 407 sedan and measures 4815mm. Interior space is greater than the outgoing 406 Coupe’s, and a folding rear seat improves the car’s versatility. As well as the aluminium bonnet,
a composite bootlid helps cut weight. As part of the standard seven airbag system, both driver and front passenger airbags have two generators and a dual volume, with deployment pressure and volume depending on the severity of the impact. Doors and boot are automatically locked at speeds higher than 10km/h and the electric windows are equipped with a safety auto reverse mechanism.
“This is the first time a luxury sports coupe model with a diesel engine has been offered in New Zealand,” said Steve Kenchington, general manager of Sime Darby Automobiles, the New Zealand concessionaire for Peugeot. “It is a significant development that reflects the refinement and high performance output of the latest generation diesel motors.”
Engines and other mechanical stuff
The 407 Coupe’s 3.0-litre V6 petrol engine develops maximum power of 155kW and peak torque of 290Nm, the latter at 3750rpm. The petrol V6 has a new exhaust system with an active dual-mode silencer. By controlling the input of gases into the silencer according to driving conditions, the system reduces noise during normal motoring and increases performance under high load.
The engine block and cylinder heads are light alloy, and there are four valves per cylinder. Engine management is by a Bosch ME 747 unit controlling a phased sequential injection.
The all-new DT17 TED4 2.7-litre V6 diesel develops 150kW of power, and a massive 440Nm of peak torque at 1900rpm, ensuring smooth and highly flexible power delivery. A compact graphite cast-iron construction helps keep the weight of the engine block low. Peugeot says the method of construction brings durability improvements and superior noise insulation.
At 199kg, the diesel weighs only 15kg more than the petrol V6. The double overhead camshaft (DOHC) diesel has four valves per cylinder and aluminium cylinder heads. Its intake system has two low-inertia turbochargers (one per bank of cylinders) with an air/air intercooler. Both turbos are electronically controlled, giving improved performance and reduced emissions. Electronic control is also used for the injectors, and the V6 diesel engine is fitted with a third-generation maintenance-free particle emission filter (FAP).
Improvements to the additive and filter core mean the emission filter doesn’t need to be replaced until the car has done 210,000 kilometres. Mechanical refinements include a new engine mounting system with vertical active link rods which eliminate vibrations transmitted to the body at low engine speeds.
The six-speed manual gearbox is available on the petrol 407 Coupe, and the new AM6 six-speed transverse automatic transmission is offered on both petrol and diesel versions.
The compact new auto has three modes – full automatic, sport and sequential with manual gearchanges for all six gears using Porsche Tiptronic control.
The 407 Coupe’s body has high torsional rigidity. By shortening the springs at the front and rear, Peugeot engineers have lowered the height of the body. To limit roll, stronger rear springs enhance supension rigidity, and the bump stops are shorter and firmer than on the 407 saloon and SW (wagon). Double wishbone suspension is used at the front; at the rear is an integral multi-arm set-up.
Aluminium is used in the car’s suspension and the front track is 19mm wider because of a larger wheel offset. To control roll, the front anti-roll bar on both the petrol and diesel models have increased diameter over the sedan and SW. Inclined spring and damper assemblies are used in the multi-arm rear suspension. On each side a drop-link longitudinal arm eliminates vibrations. By adopting wider and more rigid hub assemblies and by using a larger wheel offset, the rear track of the Coupe has been widened by 45mm over the other 407 models’.
The 407 Coupe gets special damper settings, and a new electronically controlled suspension is used with variable shock absorption and independent control of each damper. A wheel travel sensor controls each wheel independently in accordance with nine damper settings. At the touch of a button the sport mode firms up the settings. The continuously-variable hydraulic-assisted steering is computer-controlled, offering more assistance at lower speeds and a wide range of power steering variations. Front brakes are 330mm ventilated discs; rears are 290mm.
Emergency brake assist is linked to the speed at which the brake pedal is depressed, and during heavy braking the hazard warning lights are automatically activated. In addition to traction control (ASR) acting on the brakes and the engine, the car’s stability control (CDS) continuously compares the steering wheel angle, rate of yaw, speed of the wheels and lateral acceleration to detect the start of understeer or oversteer.