Starting from $38,990, the new Rex has seen substantial technical changes from the previous model, including a smaller engine, new transmissions options and upgrades to the chassis, transmission, brakes and other areas.
The engine sees the WRX go back to a 2.0-litre four-cylinder engine with direct injection from the previous generation's 2.5-litre unit. The new Boxer engine, which was first unveiled in the Forester turbo, has 197kW of power (at 5600rpm) and 350Nm of torque (at 2400-5200rpm) in its WRX configuration, which slightly outperforms the previous model’s 195kW and 343Nm.
In manual form the new 2015 Suabru WRX accelerates from 0-100km/h in 6.0 seconds. Despite the downsizing and additional performance, fuel economy has improved by 11.5 percent
The previous model's five-speed manual has been swapped for a six-speed manual (but not the same unit as the one found in the Subaru WRX STI), while a continuously variable transmission (CVT) with eight artificial gears brings back an automatic option to widen the WRX's market appeal.
Technically, there has been substantial changes to the new Subaru WRX. The fourth-generation model offers sharper steering, now using a smaller diameter D-shaped steering wheel.
The electric power steering sees its steering ratio at 14.5:1, while Subaru has increased the gearbox mount bushing stiffness by 230 per cent.
The front and rear suspension has been changed as well, with the front gaining stiffened cross-members, more rigid control arm bushings, thickened strut cylinders, larger stabiliser bar (diameter up from 21 to 24 mm), higher spring rates (up 39 per cent), lower transverse link rear bushings (10 mm lower), addition of stiffening plates, a thicker front control arm plate and increased lateral stiffness by up 14 per cent are just some of the changes.
The rear suspension uses a stiffened subframe and trailing link bushings while have its rear lateral outer bushings changed to racing-type pillow ball. Like the front, the stabiliser bar diameter has increased (from 19 to 20mm), while the spring stiffness has increased by 62 per cent.
An additional 3mm of initial toe-in has been added alongside rear subframe supports while the shock mounts on rear lateral arms have moved 10mm outward. The changes result in a 35 per cent increase in lateral stiffness for the rear.
Much like the new STi, the WRX has seen body rigidity improved significantly. The new car features a nine per cent increase in use of 590 MPa steel while adding 980 MPa steel for the first time (four per cent of the body). In total, torsional rigidity has been increased by around 40 per cent while bending rigidity is up approximately 30 per cent.
The engine, though closely related to the Forester XT powertrain, has stronger valve springs than its bigger brother. It also allows for a 25 per cent improvement in the manual transmission version's redline to 6700rpm (6500 for Sport CVT), has a longer chain guide, lighter exhaust system, roller rockers for valve actuation and a plastic intake manifold to reduce weight.
The turbo is also now mounted immediately under the boxer engine (86.0 mm x 86.0 mm bore x stroke), which sees its crank pins increase from 48 to 50mm.
The exhaust system brings the same boxer sound, now better tuned with the removal of abolishing a cylinder chamber and shortening the inside pipe.
Brakes have been upgraded to 12.4 inches (up from 11.6), while the thickness has increased by 6mm to 30mm, which Subaru says helps reduce brake fade by up to 40 percent.
All WRX models ride on 17-inch wheels, which though weigh the same as the previous model, have a five per cent increase in rigidity.
A 25mm increase in the WRX's wheelbase allows for more room inside, which has been widened by 15mm. The boot space is up 40 litres (to 460L), while the thinner A-pillars have come forward by 200mm, allowing for small quarter windows.
The new front sport seats allow for greater travel, up to 60mm (from 20mm), while the backrest is 60mm taller.
Subaru Australia will offer two variants, a base model and a WRX premium which gets additional equipement (more on that here). It will go on sale today and is available in seven colours: crystal black silica, crystal white pearl, dark grey metallic, galaxy blue silica, ice silver metallic, red and the traditional WR Blue Pearl.
Read: 2015 Subaru WRX Review
2015 Subaru WRX manual $38,990
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