The ZT 260 is a fully
engineered evolution of the front-wheel drive ZT. Clever installation
techniques have permitted the larger capacity engine and rear-wheel drive
power-train to be incorporated within the robust bodyshell, without major
visual changes. Below the skin the platform is largely new with
significant changes to many functional vehicle systems to accommodate the
revised drive-line layout, to produce a car of great driving character.
Recently a development ZT-T
V8 was taken to the Salt Flats at Bonneville, Utah where the MG achieved a
maximum speed of 225mph from a specially tuned V8 engine variant.
Design and Development
The development engineers
were briefed to deliver the ultimate antidote to an anodyne world. The
challenges involved in transforming the drive platform and packaging a
large capacity V8 engine into the existing front-wheel drive vehicle
should not be underestimated. Advanced computer techniques were used to
package the new hardware without sacrificing the strengths of the
established ZT platform. Sophisticated modelling techniques were used to
refine the kinematics of the completely new multi-link rear axle
configuration and to ensure that despite the revised engine installation,
the car continues to meet the latest standards for occupant protection in
all its markets.
Given the magnitude of
the changes, it is no surprise that ZT has been extensively tested, seeing
action in climates ranging from the bitterly harsh conditions of the
Swedish winter through to the burning heat of high speed testing in
Arizona and Australia.
Body Structure
Externally there is
little clue to the extent of body structure changes necessary to
accommodate the new rear-wheel drive powerunit, indeed ZT 260 shares the
same acclaimed style of the front-wheel drive ZTs. Extensive changes have
been made to the underfloor, with new designs for the front and rear
floor, as well as an enlarged transmission tunnel to accommodate the
in-line gearbox. A new manufacturing facility has been commissioned
alongside the existing sophisticated ZT manufacturing line to ensure these
changes to the body are delivered to consistently high quality standards.
Powertrain
The ZT 260 utilises
Ford’s proven 4.6-litre V8 engine, widely used in North America to power
the iconic Ford Mustang. Modifications have been made to the powertrain
to assist in packaging the engine while MG’s engineers have also developed
new intake, exhaust and emissions control systems to ensure the vehicle
complies with stringent European noise legislation with no loss of power
or torque. A new electronic engine calibration helps ensure the car
exceeds current European emissions legislation.
The exhaust system,
twinned for most of the length of the car, is distinguished by new
quad-tailpipes. Outside the system produces a classic V8 burble, while
inside the cabin remains quiet until aroused by the throttle when it
resounds to the sporting note of a true thoroughbred.
ZT 260 features Tremec’s
TR3650 five-speed manual gearbox, manufactured in North America. The unit
has been extensively modified to meet MG’s needs and features unique
gearing to suit the demands of European driving. MG’s engineers have also
developed an all-new gear selection system and bespoke hydraulic clutch
actuation to ensure precise and positive gear changes.
The rear axle features
Dana’s Hydratrak® limited slip differential system, which utilises
vane-pump principles to ensure continuous and seamless torque transmission
to both rear wheels in the event of wheel speed differential.
Steering and
Suspension
The ZT 260’s steering and
suspension systems have evolved radically to match the performance of the
V8 power unit. Developed by driving enthusiasts for enthusiasts, the team
focused their efforts on honing the car’s classic rear-drive handling to
provide seamless, fluid and adjustable attitude control under the widest
range of conditions. The result is a car that blends day-to-day ease of
use with the driver-rewards of a true thoroughbred.
Power steering, driven by
a higher capacity pump, is now via a new forward mounted rack layout
providing excellent feel and driver feedback to the leather-bound wheel.
The geometry of the ZT’s
MacPherson strut front suspension has been tuned to the requirements of
the new chassis platform. A new design of upright is matched to Eibach
linear rate springs and a new, larger diameter anti-roll bar. Wheel
response is controlled by Bilstein monotube struts, which combine a large
piston area for fine tuning resolution with very high bending stiffness
for improved camber control. The design employs a significantly revised
subframe, which provides a stable operating platform for the chassis while
also acting as a key loadpath in the event of a major impact.
A new multi-link rear
suspension has been developed specifically for the
ZT 260 V8. A new six-mount subframe houses the Hyrdratrak® differential,
while each wheel is located by three lateral links (two steel and one
light-alloy) and a light alloy trailing arm. Compound rate springs, also
sourced from race specialist Eibach, work in conjunction with Bilstein
monotube dampers to provide excellent wheel control. Roll behaviour is
controlled by a new anti-roll bar.
Both ZT 260 models
feature 18” alloy wheels; the attractive ‘Straights’ design is specified
on the ZT 260 with a new ‘Apex’ 10-blade design on the ZT 260 SE.
Contisport 225/45 ZR18 tyres balance excellent lateral stability with
crisp, precise steer response.
Braking
ZT 260 has a new H-split
braking system providing excellent stopping power. At the front, proven
large capacity 325mm ventilated discs and sliding-pin callipers are
specified. At the rear a new AP-Racing sourced brake system is specified
with 332mm ventilated discs and opposed piston alloy callipers.
Interior environment
A new HEVAC (Heating,
Ventilation and Air conditioning) unit is fitted to the ZT 260. The new
unit is a water-blend design featuring a dedicated electronic control unit
to drive servo-motor valves to regulate the water flow around the heating
circuit. This system has been refined to offer similar levels of response
and control to the existing ZT’s acclaimed air-blending system. All
models feature ATC (Automatic Temperature Control), using the familiar
user-friendly interface of other ZT models.
A discreet V8 badge in
the centre of the fascia differentiates the interior of the car, while
other aspects of the cabin environment are broadly similar to the existing
ZT models.
A new moulding below the
boot floor accommodates the relocated battery and the CD autochanger
(standard on the ZT 260 SE). Major controls, which include steering,
clutch and gear selection have all been refined to suit the ZT 260 V8’s
more muscular character.
Black leather trim,
highline satellite navigation that includes a Teletext equipped TV tuner
and park distance sensors are but a few of the features that distinguish
the SE. |