Overview: Peugeot 508

Peugeot’s new large saloon, the 508, is due to make its début in the U.K. in April 2011. It is, despite its inconsistent numbering, a direct replacement for the slightly smaller 407. Like its predecessor, the 508 is available in berline or station-wagon derivatives. The 5008 people-carrier, which has been available for over a year, shares many components with the new car.

In its launch material for the 508, Peugeot rather daringly refers to the first car to wear a ‘50x’ badge, the legendary 504. It’s hard to imagine any modern car following in the tyre tracks of the 504, across African bush with the entire contents of someone’s house on the roof. But perhaps it’s just the vague notion of past glories that Peugeot had in mind.

Rennes was the first PSA Peugeot Citroën plant to produce Peugeot and Citroën vehicles on the same platform.

Known internally as W2 — not, presumably, a reference to Bayswater — the 508 is based on PSA’s Platform 3, which is used for all of the Group’s upper medium and executive models, all of which are built at Rennes in France. Compared with the 407, the 508’s wheelbase is 92mm longer, while overall length is up by 116mm. But the proportions have changed, with the 407’s rather extreme front overhang of 1029mm down to 985mm on the 508, while a longer rear overhang frees up more luggage space.

Quoted luggage capacities are 515l (VDA) for the saloon and 560l for the S.W. With the seat backs folded to form a flat floor, this volume rises to 1381l for the saloon and 1598l for the S.W.

Aerodynamic performance is good, with the more modestly-equipped French-market saloons — wearing the narrowest tyres — delivering a drag coefficient of Cd 0.26 and a CdA of 0.60m². British market models, with better equipment levels, start at CdA 0.62m².

Peugeot 508.

Despite the increase in wheelbase and overall size, kerb mass engine-for-engine has been reduced slightly over the 407, though the 508 is certainly no featherweight:

Peugeot 508
HDi 112
HDi 110
Kerb mass (kg) 1405 1430
CdA (m²) 0.62 0.64
CO2 (g/km) 124 129

The 508’s collapsible structure at the front includes shock-absorbing structures on the front beam, which allow a reduction in the length of the front overhang.

Mass-reduction measures include the use of a magnesium fascia panel cross member, an aluminium bonnet — though the 407 also had this feature — and laser welding of the roof.

It’s worth bearing in mind that the 407 in its time also incorporated mass-reduction measures. Light alloys were used for bulky suspension components, with the choice of Cobapress aluminium for parts with complex shapes (the hub carrier in particular), as well as that aluminium bonnet. Cobapress aluminium is a ‘cast-turned-pressed’ material that offers the same mechanical properties as a forged component.

Peugeot 508 S.W.

Peugeot boasts of its use of ‘green materials’ in the 508 to reduce the car’s carbon footprint. In this, it is referring to materials produced from recycling, or materials that are natural in origin. In a 508, around 14.3 per cent. of the 230kg of polymers (excluding the rubber) are ‘green’ materials; this compares with six per cent. for the 407. These green materials can be found in roughly 30 vehicle parts or functions — for example, the interior of the wheel housing, the rear bumper, noise insulation, boot carpet, steering wheel, seats, seat frames, engine cover and the air filter.

In Peugeot’s thinking, the 508 comprises five main groups of materials: metals, plastics, fluids, rubber and glass. Overall, 85 per cent. of the mass of the 508 is recyclable; 95 per cent. is ‘upgradeable’. In the same spirit, on the Rennes production line, work to minimise protective packaging has seen a 75 per cent. reduction in waste in relation to the parts used for each car.

Engine outputs range presently from 112PS to 204PS. The range includes Peugeot’s e-HDi system — an HDi engine with a stop-start — and will eventually include the Company’s Hybrid4 technology. At launch, the top-of-the-range engine is the new 2.2-litre HDi 204PS unit; this offers a level of performance superior to the previous 407 V6 HDi but with a carbon footprint reduced by more than 30 per cent.

The 508 will be available with two types of front suspension. Most of the range will use a new McPherson set-up, which saves 12kg over the drop-link double wishbone arrangement of the 407. But the simpler design is apparently not man enough for the HDi 204PS engine, so these models — designated GT — will use a development of the 407’s wishbone set-up. The dual wishbone suspension decouples bounce and steering functions. A multi-link system is deployed at the rear on all derivatives; this arrangement, in turn, decouples longitudinal and lateral cornering forces.

Electro-hydraulic steering is standard. The braking system uses three sizes of front discs:

x 26mm
x 28mm
x 30mm
VTi 1.6
HDi 112
HDi 140
THP 1.6
HDi 163

All 508s come with ESP, which includes CDS (stability control), AFU (emergency brake assist) and REF (electronic brake force distribution). The ESP also includes Hill Assist and intelligent traction control, which improves the vehicle’s ability to move off and be driven on slippery road surfaces by controlling wheel-slip.

Measures aimed at improving refinement include acoustic encapsulation of power trains, the fitment of an acoustically-coated front windscreen as standard, and an active damper on the front axle of the 2.2-litre HDi 204PS version to reduce engine vibration.

The 508 is fitted with a colour head-up display which projects information from the rear of the instrument panel onto a glare-proof translucent smoked polycarbonate panel. It provides information about speed, cruise control and speed limiter speeds, and satellite navigation instructions.

Apparently drivers are using main beam headlights less often these days, no doubt because of increased traffic. The 508 is available with adaptive main beam headlights: this system uses a camera positioned behind the rear-view mirror to analyse light patterns, identifying approaching or following vehicles, brightly lit urban areas and so on. It then uses this data to switch automatically between dipped and main beam according to conditions. This system comes with directional bi-xenon headlamps, which adapt to different driving conditions between 5km/h and 160km/h.

Static directional lighting, which is standard on all 508s with either bi-xenon or halogen headlamps, is designed to improve lateral visibility at low speeds — less than 40km/h — in urban areas, at intersections, during parking manoeuvres, on winding roads and so on. The light beam from one of the two fog lights illuminates the inside of the corresponding bend, according to the angle of the steering wheel or use of the direction indicator.

A hands-free access and start-up system is available on some models. It replaces the mechanical key with electronic recognition. By keeping the ‘electronic key’ in their pocket or bag, the driver can enter the car, start and stop the engine. The transponder has a range of 1.8m. When getting out of the car, simply brushing a hand over one of the handles is enough to lock the car — this includes the tailgate handle on the S.W. If the electronic key is accidentally left inside the vehicle, the car cannot be locked. And if the driver leaves the vehicle with the engine running, the key immediately gives an audible warning.

An electric parking brake is fitted as standard from mid-range models upwards. When starting off, the hand-brake is released automatically as soon as the driver starts to accelerate. When the engine is switched off, the brake is activated, automatically. If the vehicles stops without the ignition being switched off, the electric control, located within reach of the driver’s left hand, can be activated manually. Bizarrely, manual release requires one foot to be on the brake: it is impossible for the driver to coordinate the take-up of drive with the manual release of the parking brake.

All 508s, regardless of their powertrain, are equipped with the Hill Assist system. When stopped on a gradient, this function keeps the vehicle immobile for around two seconds after the brake pedal has been released. The system operates on gradients of 3 per cent. and over; the car’s ESP system then temporarily maintains braking pressure.

The 508 uses PSA’s e-HDi stop-start system for the first time. Reductions in fuel consumption and CO2 emissions of up to 15 per cent. are claimed for town driving. The stop-start system is mated to the 1.6-litre HDi engine coupled with the electronically-controlled BMP6 six-speed manual gearbox.

Initially, the e-HDi model delivers a combined fuel return of 64.2mpg (4.4l/100 km) for emissions of 114g/km. During 2011, electronically-controlled air intakes will be instroduced, pulling the model’s CO2 yield below the 110g/km mark.

PSA’s new 2.2-litre HDi 204PS engine is fitted to the top models in the 508 range. Designated GT, these derivatives feature a double-wishbone front suspension set-up in place of the McPherson arrangement used for all lesser models.

This power-train delivers a level of performance superior to the former 2.7-litre HDi V6 fitted to the 407, together with greatly reduced fuel consumption — down 33 per cent., with commendable overall CO2 emissions of 150g/km. This compares with the V6’s 223g/km — a reduction of 73g/km.

The new 204PS engine, designated DW12C, is a substantial redevelopment of the earlier 170PS DW12B unit. Like the two-litre DW10 units, it features a four-valve light alloy cylinder head with dual overhead camshafts atop a cast iron block. The camshafts are driven by a toothed belt. Unlike the smaller engines, its block is fitted with twin balancer shafts. Like all of the diesel engines used in the 508, camshaft timing is fixed and turbocharger nozzle geometry is variable.

Curiously, the DW12C’s fuel supply rail is run at 1800 bar (180MPa) rather than the 2000 bar of the two-litre engines, suggesting that PSA is slightly derating this unit — perhaps to keep its torque output within the limits of the available transmissions.

Compared with the earlier ‘B’ engine, maximum torque has gained no less than 80Nm to 450Nm, delivered between 2000rpm and 2750rpm; the old 170PS unit delivered its maximum torque at 1500rpm.

As you might have suspected, overall rolling-road fuel consumption has improved, in this case by nearly 20 per cent. compared to the DW12B.

The 2.2-litre engine uses a new version of PSA’s ECCS (Extreme Conventional Combustion System) diesel combustion chamber. The compression ratio drops from the 16.5:1 of its predecessor to 16.0:1, while maximum boost pressure is a formidable 2.20 bar. Its injection system uses piezo-electric injectors with eight apertures, compared to seven previously. The engine is controlled by new ECUs, and the impeller of the variable-geometry turbocharger is now made of titanium.

To reduce engine friction, a new type of gudgeon pin and piston-rings with hard coatings are deployed; between them, these measures are responsible for a claimed saving of more than 5g/km of CO2.

The 508 uses ‘intelligent’ or selective battery charging, which PSA calls Voltcontrol. Like other systems seen elsewhere, Voltcontrol takes the alternator off-load during acceleration, allowing it to do most of its work during overrun. This provides a quoted saving of nearly 5g/km of CO2. Additionally, the engine idle speed has been cut from 820 to 700rpm, and the overall weight of the engine has been reduced by nearly 5kg compared to the DW12B,

Entry-level 508 diesels use the familiar PSA-Ford co-op engine, know within Peugeot as the DV6. It uses a light-alloy two-valve cylinder head on an aluminium block; there are two camshafts, driven by a toothed belt.

Two versions of the DV6 are deployed, both producing 112PS at3600rpm. One delivers 240Nm and is fitted with a five-speed gearbox; the other offers 270Nm, and comes with PSA’s electronically-controlled six-speed manual transmission. This is the e-HDi version, which also boasts a stop-start system. Both versions feature a modest 1650 bar (165MPa) fuel-line pressure.

The 1.6-litre EP6 petrol engine is also a familiar unit, in this case developed in collaboration with BMW. There are two markedly different versions, both with a four-valve light alloy head and aluminium block. The twin overhead camshafts are driven by a chain.

The basic type, known as EP6C, is an indirectly-fuelled atmospheric unit of 120PS. Both of its camshafts have variable timing, and the inlet side also has variable lift.

The more powerful of the 1.6-litre petrol engines is directly fuelled and turbocharged, with a headline output of 156PS. The blower is of the twin-scroll type with fixed geometry. Camshaft timing is continuously variable, though there is no provision for adjusting the intake valve lift.

A new six-speed automatic gearbox, designated AM6, makes an appearance on the 508. Developed by Aisin AW according to PSA’s specifications, it has a torque capacity of of 450Nm and features several of the technologies which appeared in 2010 on the AT6 six-speed automatic. The latter unit is fitted to the 1.6-litre THP 156PS petrol engine on a number of models, including the 508.

Various approaches have been taken to reduce energy absorption by the new transmission, the most important of which is probably the reduction of internal friction. Bearings, segments, clutch linings and oil specification were targeted. In all, PSA reckons that the new AM6 gearbox saves 13g/km of CO2 compared with the unit’s predecessor.

Gearchange times have been reduced, principally by the adoption of a directly-controlled hydraulic block. The transmission’s controller offers multiple downchanging.

In Sport mode, gear-change times are cut by a further 200ms compared to Drive mode. In sequential mode, the driver uses paddles under the steering wheel; this is a feature of all automatic 508s, and of the electronically-controlled manual versions. The paddles can be used at any time to override automatic gearchanges. The central selector lever also offers sequential control: forward to change down, and rearward to change up.

A Hybrid4 version of the 508 will be introduced in 2012. As we have reported elsewhere, this technology uses an HDi diesel at the front — driving the front wheels, as usual — and an electric motor at the rear, driving the rear wheels. In the case of the 508, Hybrid4 offers a potential combined maximum power of 200PS as well as four-wheel drive. Peugeot is targeting a CO2 yield of 99g/km for the 508 Hybrid4.

Most vehicles in the 508 range are supplied with the Peugeot Connect system. This gives the owner free access to the Peugeot Connect SOS service for an unlimited time, as well as to Peugeot Connect Assistance. For professional customers, via subscription, the Peugeot Connect Fleet service (automatic uploading of information relating to vehicle maintenance) is also available. Peugeot Connect SOS presently works in 10 European countries and has so far been fitted to around 400,000 cars. It pinpoints the location of the vehicle and enables the dispatch of appropriate emergency services in the event of an accident. Since its launch in 2003, it has facilitated rapid intervention by the emergency services in more than 4,000 emergencies.

In Europe, two thirds of customers for this type of car are corporate.

What’s in a platform?

In PSA-speak, the word ‘platform’ covers all parts and components shared by several vehicles produced by Peugeot and Citroën. These components include sub-frames, engines, transmissions, whole power-trains, seat frames, fuel tanks, engine control units, suspension and steering components, air conditioning, cooling, and brake systems. It does not necessarily refer tp a specific floorpan pressing.

The platform system makes it possible to use and reuse a large number of components that are invisible to the customer. Two vehicles are considered to share the same platform when shared parts account for at least 60 per cent. of their production cost.

A key feature of the platform system is its modularity. This allows for the integration of each model’s specific features and a wide range of vehicle formats. For example, cars can differ in length by nearly 60cm and still be built on the same chassis, just by changing the rear-end module.

The platform system was devised at the turn of the century and first became a reality in 2004, when the first Platform 3 vehicles went into production at Rennes. Platform 3 is for vehicles in the M2 and H categories, and the first products to use it were the Peugeot 407, 407 S.W. and 407 Coupé, and the Citroën C5 and C6. Platform 2 is for M1 vehicles like the Peugeot 308 and Citroën C4; Platform 1 is for B-category superminis.

There is also a geographic rationale behind the strategy. Each assembly plant is organised around a single platform. Small cars on Platform 1 are built in the Paris area — Aulnay and Poissy — as well as in Madrid, Porto Real (Brazil) and Trnava (Slovakia). Platform 2 vehicles are built in eastern France — Mulhouse and Sochaux — plus Vigo (Spain), Buenos Aires (Argentina) and Wuhan (China). Platform 3 is the exclusive preserve of the Rennes plant.

PSA sees the platform strategy as enabling the Group to accelerate the pace of new model launches and expand its vehicle ranges. Other advantages are an increase in production volumes and better control of costs through the use of shared parts. Development costs are minimised, by sharing components between a large number of models. By minimising time wasted on developing multiple components where one will do, attention and resources can be focused on creative and research activities.

The Group has also developed five platforms with other carmakers:

  • Two in cooperation with Fiat, for MPVs and commercial vehicles.
  • One with Toyota, for compact cars produced at the Kolín plant in the Czech Republic.
  • One with Mitsubishi for 4x4s.
  • One with Fiat and and its Turkish associate Tofas for LCVs.

A replacement for Platform 2 is due to be deployed some time in 2012. Designated BVH2', it promises greater modularity.

508 saloon
VTi 120 THP 156 HDi 112 HDi 112 HDi 140 HDi 163 HDi 204
Cylinders 4I 4I 4I 4I 4I 4I 4I
Valves 4 4 2 2 4 4 4
Swept volume 1598cc 1598cc 1560cc 1560cc 1997cc 1997cc 2179cc
Head/block a/Al a/Al a/Al a/Al a//Fe a//Fe a//Fe
11.0:1 10.5:1 18.0:1 18.0:1 16.0:1 16.0:1 16.0:1
P/id P/d D/d D/d D/d D/d D/d
Fuel line
pressure (MPa)
N/A 12 165 165 200 200 180
Aspiration A Tts T T T T T
N/A 1.00 1.50 1.50 1.70 1.70 2.20
PS/rpm 120/6000 156/6000 112/3600 112/3600 140/4000 163/3750 204/3500
Nm/rpm 160/4250 240/1400 240/1500
340/2000 450/2000
Maximum speed 125 134 116 119 129 137 143
0-100km/h 11.5 8.6 11.3 11.9 9.8 9.2 8.2
Urban MPG
Combined MPG
CO2 g/km 144 154 124 114 (1) 125 149 150
Emissions EU5 EU5 EU5 EU5 EU5 EU5 EU5
Transmission AM6 M6 (A6) M6 AM6 M6 A6 A6
Driven wheels Front Front Front Front Front Front Front
Fuel tank 72l 72l 72l 72l 72l 72l 72l
Kerb mass † 1390 1400 1405 1410 1430 1520 1540
PS/t 86 111 79 79 98 107 132
Nm/t 115 171 170 191 223 223 292
Dimensions Click here
CdA (m²) 0.62 0.62 0.62 0.62 (2) 0.62 0.60 0.65
* Overboost.
(1) To be reduced to 109g/km during 2011.
(2) To be reduced to 0.58m² during 2011.
† DIN kerb mass for saloon models. S.W. models are 20kg heavier. For E.U. kerb mass, add 75kg.
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