New Subaru Impreza In Depth

Press Release

Affordable, Attractive Range

The UK range goes on sale in September with the practical Impreza 1.5R costing an incredibly affordable £12,495 On-The-Road. An automatic version is available for £1,000 more. The previous Impreza 1.5R – introduced for the first time towards the end of last year – proved such a success that stocks quickly ran out.

Standard equipment on the new 1.5R includes: AWD with dual-range, low ratio transfer ’box, 15 ins alloy wheels, climate-control air-conditioning, four-speaker radio/CD player, front and rear electric windows, reach and rake-adjustable steering wheel, front fog lamps plus driver, passenger, side and curtain airbags and a vehicle information display (trip computer).

Equally outstanding value is the new Impreza 2.0R – also available from September – priced at £14,995 On-The-Road. Compared to the 1.5R, the 2.0 litre model adds: larger 16 ins alloy wheels, Subaru Vehicle Dynamics Control, windscreen-wiper de-icer, xenon headlamps and heated door mirrors. An automatic version is available for another £1,000.

The Impreza 2.0RX adds not only extra equipment but also body styling enhancements such as front and rear spoilers, side skirts, a chrome exhaust end-cap and a rear bumper diffuser. The alloy wheels are larger at 17 ins and interior upgrades include ‘Smart Entry’ with an engine push-start button and satellite-navigation.

Also standard is a leather-covered steering wheel and gear knob, cruise-control and a 10-speaker radio/single-disc CD system. The Impreza 2.0RX costs £17,495 OTR with an automatic version available for £1,000 more.

Meanwhile, sure to delight performance fans is a limited quantity of turbocharged Impreza 2.5 WRX models expected to become available during November. Prices will be announced nearer the time.

Standard equipment on the Impreza 2.5 WRX includes 17 ins alloy wheels, front and rear spoilers, side skirts, a rear bumper diffuser, leather-covered steering wheel and gear knob, a rear limited-slip differential with Subaru Vehicle Dynamics Control, 10-speaker, six-disc radio/CD player and xenon headlamps.

However the ultimate model will be the Impreza 2.5 WRX STI – due in spring 2008 when power, performance, pricing and equipment levels will be announced. This model will be visually more aggressive than the rest of the five-door Impreza range and will form the basis for the 2008 Subaru World Rally Championship entry.

New 1.5 Litre Engine In Detail

Subaru has built an enviable reputation for reliability, long engine life and accessible performance through the design of its horizontally-opposed, all aluminium ‘boxer’ engines. This ‘flat-four’ layout gives a lower centre-of-gravity for enhanced cornering grip.
It is also ideal when mated to Subaru’s standard symmetrical all-wheel drive system because of the engine’s compactness, light weight and ability to connect with the AWD transmission in a straight line.

Now, the new 1.5 litre ‘boxer’ engine has been designed to offer strong low to mid-range pulling power, known as torque, while also having the ability to rev to high speeds for brisk overtaking.

So despite being the least powerful Subaru, the new Impreza 1.5R makes the most of its power and torque, providing comparable performance to most similar-engined lower-medium hatchbacks.

For example, top speed is 109 mph for the manual, with a 0-60 mph time of 13.7 seconds. Fuel economy is also respectable with 29.4 mpg on the Urban Cycle, 44.8 mpg on the Extra Urban Cycle and 37.7 mpg Combined – 2 mpg better than before. Exhaust emissions are also competitive at 176 g/km.

Power is now 107 PS (2 PS more) at 6,000 rpm and torque is 104.7 lb.ft at a low 3,200 rpm while the compression ratio is 10.1:1. However, the torque is greater at lower engine speeds than with the previous model, improving throttle response and flexibility.

As with all Impreza engines, the new 1.5 litre features twin overhead camshafts per cylinder bank (DOHC) plus an Active Valve Control System (AVCS) which is a form of variable valve timing. This enhances both low-speed pulling power and high-rev response.

Also shared is an electronic throttle for more responsive acceleration plus centrally-located spark plugs, pent-roof combustion chambers and multi-point fuel-injection with an ignition coil for each cylinder.

Of special interest is the 1.5 litre’s bore and stroke dimensions, selected to optimise combustion efficiency for low emissions and fuel consumption while providing strong power and torque.

In fact, the new 1.5 litre shares its 79 mm stroke with Subaru’s four-cylinder 2.5 litre turbo engine. Naturally, its bore dimension is a much narrower 77.7 mm.

Other efficiency measures include low-friction, lighter valve springs and a 4-2-1 equal length, ‘constant-pulsation’ exhaust system which avoids gas flow interference and speeds up the warm-up of the catalytic converter.

Ten-Speed Transmission/Symmetrical All-Wheel Drive

As with the new Impreza 2.0R and RX, the 1.5R has a five-speed manual gearbox with a low-ratio, dual-range transfer gearbox, effectively providing 10 speeds. Owners find this particularly useful when towing or covering difficult road surfaces as it provides extra engine-braking for greater control.

For the new model, the Impreza 1.5R has revised, slightly higher 2nd, 3rd, 4th and 5th ratios for improved high-speed refinement and enhanced fuel economy.

The symmetrical all-wheel drive system features a nominal 50/50 front to rear torque split. However, a centre viscous-coupling senses which axle has the best grip and varies this ratio in milliseconds according to the road surface.

This maximises tyre grip and handling accuracy, instilling confidence in the driver – especially on rain-soaked motorways or snowy country lanes.

New 2.0 Litre Engine In Detail

The new Impreza 2.0R and RX enjoy substantial revisions to their 2.0 litre ‘boxer’ engines which result in stronger low and mid-range pulling power, enhanced flexibility and improved fuel economy with lower exhaust emissions.

And while power drops from 160 to 150 PS at the same 6,400 rpm, torque is 7.4 lb ft (10 Nm) greater, recording 144.6 lb ft at 3,200 rpm.

The result is an improvement of more than 2 mpg on the Combined cycle with the manual now recording 33.6 mpg and the automatic even better at 34.4 mpg. Urban and Extra Urban figures are 25.4 and 40.9 mpg for the manual and 25.4 and 43.5 mpg for the automatic.

Exhaust emissions are also down, now standing at 199 g/km for the manual (was 214 g/km) and 194 for the automatic (was 207 g/km).

The 0-60 mph time for the manual is 9.2 seconds while the automatic records 11.3 seconds. Maximum speeds have yet to be confirmed.

Common to all new Impreza engines are twin overhead camshafts per bank (DOHC), four valves per cylinder and an Active Valve Control System (AVCS) which is a form of variable valve timing. This enhances low-speed pulling power and high-rev power.

For the new Impreza 2.0R and RX, the combustion chambers have been redesigned for increased tumble gas flow, enhanced tow-speed torque and reduced fuel consumption. Also for improved efficiency are a revised intake system, cooling system and catalytic converters.

The new 2.0 litre four-cam ‘boxer’ engine retains the same 92 mm bore and 75 mm stroke as before but with a lower 10.2:1 compression ratio.

New 2.5 Litre (WRX) Turbo Engine In Detail

The renowned 2.5 litre turbocharged ‘boxer’ engine fitted to the new Impreza WRX receives meaningful revisions to improve efficiency and provide much gutsier throttle response in ‘real world’ driving conditions.

Maximum power for the standard WRX is an identical 230 PS to the previous model but now at a lower 5,200 rpm instead of 5,600 rpm.

Torque (pulling power) is also the same as before at 236 lb ft but now at a more accessible 2,800 rpm instead of 3,600 rpm.

Significantly, torque at 2,000 rpm is now 221 lb ft instead of around 150 lb ft. This translates into much livelier acceleration from low engine speeds and an effortless seam of power in everyday driving. Power is also considerably greater from idle until 3,500 rpm.

These major improvements have been achieved thanks to a new turbocharger and intercooler with the oil pump, sparking plugs and tumble generating valve all being revised for greater efficiency.

On the transmission front, 1st, 2nd and 3rd gears have been revised and despite the lower overall gearing – top now pulls 22.6 mph at 1,000 rpm instead of 23.5 mph – fuel economy is unharmed.

The new Impreza WRX also enjoys a 30 kg weight saving and lower drag coefficient of 0.35 Cd instead of 0.37.
It has an identical 0-60 mph time as the old model at 5.4 seconds. Maximum speed has yet to be confirmed.

Fuel economy is now 19.8/34.4 and 27.2 mpg on the Urban/Extra Urban and Combined cycles while the CO2 emissions are 246 g/km.