23/4/12

Overview: Subaru XV

The XV is Subaru’s first offering in the highly competitive compact crossover market. It uses Impreza underpinnings, which means petrol and diesel boxer engines and a four-wheel drive system with a nominally 50:50 torque split. Subaru has high hopes for the car, expecting it to be the Company’s’s best seller in Britain.

Three Euro 5 power-plants are available — 1.6- and two-litre petrol, and two-litre diesel. To go with them there are no fewer than three transmissions — five- and six-speed manual, and a ‘six-speed’ CVT automatic. (The CVT pretends to have six fixed ratios when used in manual mode.)

The XV’s monocoque bodyshell incorporates a high percentage of high-tensile steel, which Subaru claims leads to the XV being one of the lightest vehicles in Europe’s compact SUV class.

The XV’s wheelbase, at 2635mm, is 10mm longer than the Impreza’s. With an overall length of 4450mm, that leaves the Subaru looking a little smaller than its obvious competitors:

Subaru XV Land Rover
Freelander
Mazda CX5
Wheelbase 2635 2660 2700
Length 4450 4500 4555
Width 1780 1840

Compared with the Impreza, the base of the A-pillars has been moved forward by a substantial 200mm, making the interior space larger and more cab-forward. Re-shaping the doors’ internal structure and their trims has increased the cabin width and boosted shoulder and elbow room. The door openings are larger than the Impreza’s and the sills have been narrowed and lowered, both with the intention of making the XV easily accessible. (The sills extend only 30mm above the floor level.)

The driver’s seat delivers the usual high hip-point we expect of this sort of car. The head-restraints have three-way adjustment — up, down and tilt — while the rear head restraints are retractable. The seat backrests are 50mm taller than the Impreza’s.

The split rear-seat backrest folds forward onto the fixed seat cushions to create an almost-flat cargo bay. In XV models with a puncture repair kit (rather than a full-size spare wheel), cargo capacity is 380 litres with the rear seats upright and 1,270 litres with the rear seats folded flat. The omission of a full-size spare wheel also liberates a 15-litre under-floor storage compartment. No figures are quoted for cars fitted with a spare wheel.

The cargo floor has been lowered compared to the Impreza, and this, combined with changes to the internal structure of the roof, creates a load bay which measures 780mm high, 820mm long and up to 1350mm wide.

The XV was recently awarded a five-star Euro NCAP crash safety rating. It received good scores in all four categories, notably 90 per cent. in the child occupant category — the best result of any car on sale in the U.K. It received maximum points for its protection of 18-month-old infants, with the XV’s side impact protection singled out for specific praise.

Subaru’s version of ESP — the Vehicle Dynamics Control (VDC) system — is standard on all XV models. The operational status of the VDC is displayed on the multi-function display screen in the centre of the dash.

For impact resistance, the XV bodyshell is equipped with a series of ‘circular links’ or horizontal hoops which join the A-, B-, C- and D-pillars with cross members at roof and floor levels. Ultra-high strength steel is used for key sections of the bodyshell to achieve extra rigidity without adding to the mass of the structure. Specific structural changes (compared with the Impreza) adopted to enhance the crash performance of the XV include a thick ‘toe board’ panel to restrict movement of the pedals in case of collision. A strengthening joint is fitted between the base of the A-pillar and upper frame, and tougher sections joining the bumper beams to the chassis for a higher level of energy absorption. Two side-impact beams are fitted within each rear door, and new diagonal cross members evenly distribute the force of an offset rear impact left and right through the chassis to minimise deformation of the cabin. Pedestrian protection is enhanced by the fitment of energy-absorbing elements inside the engine bay and the use of energy-absorbing foam in the front bumper.

For the XV, Subaru carried over the seat frames from the current Legacy, with their significantly increased stiffness and taller backrests compared with the Impreza’s seats. Front, side and curtain airbags are fitted as standard to all models, along with a new knee airbag for the driver.

The XV comes equipped with occupant mass detectors in the front seats, meaning that an air-bag will trigger only if an adult is sitting in the seat.

Additional safety features include a mechanism to retract the brake pedal and a separation mechanism installed between the bodyshell and the tilt bracket of the steering column to minimise forces generated by the steering wheel on the driver’s torso.

Engines

Subaru’s ‘EJ’ petrol engines have now been replaced with an entirely new engine family, designated ‘FB’. The horizontally-opposed four-cylinder layout remains essentially unchanged. Key features of the new FB engines are the adoption of a more undersquare design. The stroke length has been increased without making the engine any wider overall, achieved by modifying the layout of the valvegear and redesigning the cylinder block and cylinder head.

Low temperature (cooled) EGR is now used. Changes have been made also to the shapes of the intake ports and the valves and to the position of the fuel-injectors.

Two petrol engines are offered: a 1600cc unit delivering 114PS, and a 1955cc power-plant of 150PS.

Lightweight materials have been introduced for the pistons — which are 18 per cent. lighter in the case of the two-litre unit — the connecting rods and other, unspecified engine components. Also, friction has been reduced by redesigning the cooling system and by adding roller rockers to the valve-train.

Fuel economy improvements of around 10 per cent. are claimed. Factors such as a lighter bodyshell, improved aerodynamics, the adoption of a new CVT, and the automatic stop-start function have also contributed to this improvement. The stop-start system used on the XV has a respectable cycle time of 0.35s. Disappointingly, the system is not fitted to diesel models.

A new design of plastic intake manifold saves weight, while the exhaust system has been modified to ensure that the front catalyst lights off more quickly. Separate cooling circuits are used for the cylinder block and heads; Subaru claims that this speeds engine warm-up. The new Active Valve Control System has a lower lubricant requirement, so the oil pump relief pressure has been reduced. The new engine uses a maintenance-free ‘chain-type camshaft drive belt’.

The new version of Subaru’s 2.0-litre boxer diesel offers 147PS and 350Nm, and drives through a six-speed manual gearbox. The alloy cylinder block is of a rigid semi-closed deck design, while the five main bearings use metal composite supports: apart from offering strength benefits, these materials offer refinement advantages and exhibit similar thermal expansion to the crankshaft itself.

A special surface treatment designed to withstand the diesel engine’s high combustion pressures is applied to the crankshaft; the cylinder heads have been modified and have roller rocker arms. The camshafts are driven by a chain.

Revisions to the diesel engine include improvements to turbocharger efficiency, with reduced pumping losses; new exhaust-camshaft timing; optimised flow-rate in the cooling circuit; the fitment of connecting rods that are four per cent. lighter; and switching to a smaller capacity 150A alternator.

The new Boxer diesel meets Euro 5 emission standards, thanks to oxidation catalytic converters and a diesel particulate filter.

We have mentioned the (petrol-only) automatic stop-start system. This uses a unique starter motor and an ‘in-rush current reduction’ (ICR) relay. The ICR stabilises the power supply when the engine stops so that instruments and displays do not flicker. For cars fitted with a CVT, tandem solenoids are used in the starter. The time lapse between stop and start is approximately 0.2s — rather quicker than on the manual cars.

Transmissions

The standard transmission for all new Subaru XVs is an all-indirect five- or six-speed manual, depending on model. Both 1.6- and two-litre petrol engines are also available with a new version of Subaru’s Lineartronic CVT automatic as an option.

The new six-speed manual transmission for the two-litre petrol and diesel models is based on the unit found in the Legacy. There have been refinements aimed at improving fuel efficiency and gearchange quality. The spread of ratios has been expanded compared with the Legacy, and the final drive ratio lowered. One result is an exceptionally high top gear ratio — 0.557:1 for the diesel, 0.695:1 for the petrol.

The smaller petrol engine drives through a rather dated five-speed dual-range transmission.

The ‘Lineartronic’ CVT is appreciably new. Lighter and more compact than its predecessor, it is a chain-type CVT, which allows a wider range of ratios than previously as well as a quoted improvement in mechanical efficiency of up to five per cent. As we have mentioned previously, the CVT has six pre-determined ‘gear’ ratios when manual mode is selected. To reduce the likelihood of wheel-spin when setting off on icy or slippery surfaces, the new CVT transmission alows second-gear starts.

Subaru’s four-wheel drive system uses different centre differentials according to whether a manual or automatic transmission is fitted. Manual models use a viscous coupling limited-slip centre differential. The nominal, static torque split is 50:50, but whenever a front or rear wheel slips, the viscous coupling partially locks to adjust the torque distribution.

Cars fitted with the CVT use an electronically-controlled multi-plate transfer clutch to control and distribute torque to the rear wheels. The static torque split with this system is 60:40.

Running-gear

The XV’s running-gear is an evolution of existing Subaru practice. The front suspension is by McPherson struts; for the XV, the top mounts are stiffer than those of the Impreza, and the dampers use high-response valves a rebound spring to reduce body roll. Stiffer mounting bushes allow for the relocation of the front suspension arms, which results in improved and more linear steering responses and better handling. A chassis bracing beam has been added between the front cross-member and the rear mounting of the front suspension arms to reduce the transfer of engine vibration. At the rear, a double-wishbone layout is mounted on a vibration-damping subframe.

Electric power-steering has been adopted.

The XV has disc brakes at both ends. The mass of a number of components has been reduced, lowing the unsprung mass, the pressure loss when the brakes are applied has been minimised, and a spring-type return mechanism has been adopted on the front brake pads. This latter measure minimises brake drag.

Subaru XV
1.6
XV
2.0
XV
2.0 D
Cylinders 4HO 4HO 4HO
Block/head Al/Al Al/Al Al/Al
Valves 4 4 4
VVT
Aspiration/
geometry
A A T/v
Injection ID ID D
Bore/stroke 78.8/82.0 84.0/90.0 86.0/86.0
Swept volume 1600cc 1955cc 1998cc
Compression
ratio
10.5:1 10.5:1 16.0:1
PS/rpm 114/5600 150/6200 147/3600
Nm/rpm 150/4000 196/4200 350/1600
Maximum speed 111 116 120
0-100km/h 13.1 10.5 9.3
Urban MPG
(l/100km)
35.3
(8.0)
32.1
(8.8)
41.5
(6.8)
Combined MPG
(l/100km)
43.5
(6.5)
40.9
(6.9)
50.4
(5.6)
CO2 g/km 151 160 146
Emissions EU5 EU5 EU5
Transmission
— I
— II
— III
— IV
— V
— VI
— Final drive
M6 (CVT)
3.545
1.947
1.296
1.029
0.825

4.444
M6 (CVT)
3.545
1.888
1.296
0.972
0.780
0.695
4.444
M6
3.454
1.750
1.062
0.785
0.634
0.557
4.111
Driven wheels All All All
Fuel tank 60l 60l 60l
Kerb mass 1350 1355 1415
PS/t 84 110 103
Nm/t 111 144 247
Length 4450 4450 4450
Width 1780 1780 1780
Height 1615 1615 1615
Wheelbase 2635 2635 2635
Track
— front
— rear

1525
1525

1525
1525

1525
1525
Steering ratio 15.5:1 15.5:1 15.5:1
Tyres 225/55R17 225/55R17 225/55R17
Spare wheel None None None
Brakes
— front
— rear

Dv294
D274

Dv294
D274

Dv294
D274
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