All-New Mazda BT-50 Freestyle Cab at AIMS 2011

The 2011 Australian International Motor Show marks the global debut for the All-New Mazda BT-50 Freestyle Cab.

Utilising the revolutionary Freestyle door configuration first seen on the RX-8, the BT-50 Freestyle Cab offers a unique combination of seating for four, an exceptionally wide pillar-less door opening, and a large carrying capacity.

On each side of the cabin, a front-hinged door and a rear access panel combine to provide a 1,408mm-wide opening that makes for easy entry to and exit from either the front or rear seats.

Rear-seat comfort has been taken to levels never seen before in the Freestyle Cab. Cushions have been lengthened by 50mm for better thigh support and stable fitment of child seats while the seatback height has been increased by 128mm.

The rear seat cushions can be removed and with the rear access panels opening to an angle of nearly 90 degrees, the option of loading and storing cargo into the rear seating area of the cab has never been easier.

A further advantage of the All-New BT-50 Freestyle Cab is its capacious carrying capacity. The side walls of the cargo box were raised to improve the styling with a more sporty, wedge-shaped profile. This change, together with increased width and length resulted in an overall cargo volume of 1,453 litres, an increase of 266 litres over the equivalent current model.

The inner walls of the current BT-50’s cargo box have an acclaimed design that allows the space in the cargo box to be used for diverse purposes and this design has been carried forward with the new BT-50.

Improved comfort and carrying capacity

Increases in all overall dimensions of the All-New BT-50 Freestyle Cab make it superior to the current equivalent model for comfort and carrying capacity. Overall height has increased by 84mm to 1,706mm, overall width has increased by 135mm to 1,850mm and overall length has increased by 204mm to 5,373mm.

Stability has also been improved as a result of an increase in wheelbase. The wheelbase has grown by 220mm.

Increases in the interior dimensions of the All-New BT-50 Freestyle Cab means that it is one of the most comfortable and spacious in its class. Front effective headroom has grown by 10mm to now measure 1,024mm while front shoulder room has increased by 30mm to 1,440mm.

There is also now more space between rear passengers than ever and the effective rear leg room in the Freestyle Cab is also improved. An increase of 33mm means that rear passengers have 796mm of leg room.

As with all Mazda vehicles, ensuring a comfortable driving position was a major focus during development. The driver’s seat is extensively adjustable, so a driver of any size can achieve the most comfortable position. The front passenger seat has some of the same types of adjustability, so a passenger can enjoy the ride in a position that minimises fatigue.

The increased cabin length has enabled an increase in the fore-aft slide range of the driver’s seat and front passenger seat from 240mm to 260mm in both Dual Cab and Freestyle Cab.

Powertrains

New advanced diesel engines offering significant increases in power and torque with improved fuel efficiency, will ensure the All-New Mazda BT-50 range has the grunt to handle even the toughest tasks.

The headline act for the All-New BT-50 range is the new MZ-CD 3.2 litre diesel engine, in-line 5-cylinder configuration, delivering a massive 470Nm of torque and 147kW of power. This represents a 24 per cent increase in torque while power is up by 28 per cent over the current BT-50’s 3.0 litre diesel engine.

The adoption of a new high-pressure fuel system combined with advanced turbocharging ensures the 3.2 litre diesel engine delivers a more refined and responsive drive. These refinements also help to ensure that the new MZ-CD 3.2 litre diesel will be more fuel efficient than the 3.0 litre diesel engine it replaces.

The new 3.2 litre engine will be mated to a new 6-speed transmission that has been developed to exhibit low levels of noise, vibration and harshness making for a smoother and quieter ride.

The new powertrains have been developed to ensure the All-New BT-50 delivers towing capacities never before seen on this type of vehicle. The 3.2 litre engine with either manual or automatic transmission will be capable of towing up to a huge 3,350kg (braked towing capacity) delivering a 350kg increase over the current model.

Further details on model line-up and engine choices will be released closer to launch.

Increased ride quality and NVH improvements

The All-New BT-50 carries over the same sturdy ladder frame configuration of the current BT-50 but has now been completely re-designed. A number of rigidity improvements now provide for greater nimbleness and ride comfort.

The closed-section side rails have been made taller, wider and straighter. Consequently, the frame has much improved levels of rigidity (about 2.6 times the flexural rigidity and about 2.1 times the torsional rigidity of the current BT-50’s frame). High rigidity in the frame areas on which parts are mounted has also been assured, thereby realising linear vehicle behaviour and superior quietness.

The cab mounts that join the cabin to the frame suppress the transmission of vertical, longitudinal, and lateral oscillation to the cabin. The front mounts are solid rubber like those of the current BT-50. The left and right-hand mounts under the pillars at the back of the cabin are now liquid-filled. Resonance caused by the repetitive movement of the liquid damps low-frequency vibration, thereby suppressing shake for a more comfortable ride. There’s no resonance at other frequencies, so it was possible to lower the dynamic spring constant at 100Hz and higher (the frequency range relevant to booming and other kinds of noise). Since the damping force and dynamic spring constant was able to be tuned separately, it became possible to simultaneously improve ride comfort and suppress noise, vibration, and harshness (NVH).

Further comprehensive steps have been taken to suppress NVH in order to achieve the kind of quiet, comfortable driving experience that’s expected in passenger cars.

To limit vibration and noise while the engine is idling, the increased rigidity in the frame was supplemented with increased rigidity in the framework of the cabin and softening of the engine and transmission mounts.

Since vibration inputs to the cabin have been reduced, noise in the cabin by the driver’s window is reduced by around 15 per cent from the current BT-50. Vibration in the seat mounts and vibration in the steering wheel are about half of what they are in the current BT-50.

To reduce booming and road noise, the rigidity of the brackets and members that join the cabin to the frame has been increased. The higher rigidity works with the softer engine and transmission mounts to limit transmission of noise and vibration to the cabin while the vehicle is moving.

Also, an increased diameter and softer materials for the leaf-eye bushings in the rear suspension limit transmission of resonance in the powertrain to the cabin via the rear suspension (a problem that vehicles with leaf springs are prone to). Booming noise is as low as (or lower than) that in the current BT-50 at any engine speed. Damping material on the floor and other parts of the bodyshell cuts noise even further.

To keep sound that radiates from the engine and tyres out of the cabin, the seals on the body, doors and fenders have been improved. Notably, double door seals have been adopted. And to keep wind noise and the tyres’ pattern noise out of the cabin, the pillars have been filled with sound-insulating foam (a technique widely used with passenger cars).

A vehicle’s aerodynamic performance influences its high-speed driving stability, fuel economy and its interior noise. As such the quest to combine superior aerodynamic performance with the new BT-50’s fresh, striking looks was high on the agenda during development.

The airflow behind the cabin also affects drag. Through collaboration with the design studio and manufacturing teams, the shape of the rear pillars and the geometry of the rear combination lamps has been optimised for each body type.

Mazda Australia managing director, Doug Dickson, points to the significance of this global unveiling. “Just as we were delighted to be given the privilege of hosting the global debut of the All-New BT-50 Dual Cab in Sydney last year, we are equally delighted to be hosting the global debut of the Freestyle Cab in Melbourne this year. With Australia expected to be the largest market for the All-New BT-50 it’s no coincidence that we’ve been asked to host not one but two global unveilings of this important new model. It’s only appropriate that the Australian public see it first.”

The All-New Mazda BT-50 will go on sale later this year.