Most changes to Saab 9-5 are mechanical

inor facelift, major revisions under the skin: Saab’s 9-5 already had a reputation for technical innovation. That’s just been given a hefty boost.

A   new 176bhp, all-aluminium Isuzu-developed 24-valve, V6, 3.0 TiD diesel has been added to the range. But it’s no last minute affair, says Saab powertrain specialist, Jan Nyberg: “The engine has been under development by Saab and Isuzu for the last three and a-half years, and Isuzu was working on it for 18 months before that,” The TiD will be the first diesel in a European car to have a common rail system designed by Denso, rather than Bosch, Siemens or Delphi.

At 1450 bar, it is a high pressure system delivering, first a single pilot-injection, than a main injection, to reduce noise. Like other second generation common rail systems, the injectors are highly sophisticated. “They’re coded,” says Nyberg, “and the system can individually meter injections for each cycle.”

wo, variable nozzle Garrett turbochargers deliver continuously variable boost (rather than building pressure then suddenly dumping it) by opening a wastegate. Oxides of nitrogen (NOx) are finely controlled by electronic, rather than the usual pneumatic, valves.

9-5 power - new Isuzu-developed V6 3.0 Litre diesel produces 176 bhp

The chassis gets a 10 percent increase in front spring rates and a slightly thicker front anti-roll bar. Alloy steering knuckles improve stiffness by 40 per cent and reduce weight by 3kg. Wheel bearing and strut mount stiffness has been increased 100 percent, and the subframe structure by 20 percent.

Structurally, the rear end is the same, with the suspension retuned, and bigger brake calipers and 16in discs fitted all round.

Saab has also become one of the first to introduce optional bi-xenon (gas discharge, high intensity) lights on main beam as well as dip. Saab’s Valeo lights have a self-levelling system to reduce dazzle when the car is loaded -- sensors on the axles control a solenoid in each unit.