Then to the shock and horror of the car enthusiast world, BMW introduced a heavy oil burner to their engine line-up in 1983. Internally designated M21D24, this 2.4 litre straight-six was installed in the E28 5-Series, creating the 524td.
Based on the M20 petrol six, the new diesel also had a cast iron block with the same 80mm bore, but a bespoke 81mm stroke, for a swept capacity of 2,443cc. At launch, the turbocharged version produced 114hp at 4,800rpm, with 210Nm of torque at 2,400rpm, increased to 220Nm for the 1987 model year.
A naturally aspirated 524d followed in 1985, producing a rather asthmatic 84hp at 4,600rpm, with 152Nm of torque at 2,500rpm, and was only sold in limited markets. Both motor variants were also used in the E30 3-Series between 1985 and 1993, being tagged 324d and 324td respectively.
I distinctly remember driving a 524td in Germany in the mid-1980s, and it was a bit of a shock to the system to hear the diesel clatter coming from a car proudly wearing the blue and white roundel, especially upon cold start up.
However, once it was warmed through, this six-cylinder oil burner was not at all bad. Compared to the 2,316cc petrol (M20B23) motor in the 523i, which had 148hp at 6,000rpm and 205Nm of torque at 4,000rpm, the diesel’s inherently torque rich nature bestowed fairly relaxed performance on the car in normal driving. While the petrol engine was more powerful, it also required more revs to extract its best performance.
Over 30 years down the line I am sitting on the autobahn at 140km/h in the latest BMW 530d, marvelling at its near total mechanical silence. In fact the loudest external sound I can hear is the rustle of the wind on the exterior mirror to my left.
In comparison to the first generation BMW oil burner, the current B58 straight-six turbo diesel is akin to the warp drive from a Galaxy Class starship. Whether in RWD or 4WD form, the 530d’s (B57) 2,993cc TwinPower Turbo diesel develops a healthy 265hp at 4,000rpm, along with a thumping 620Nm of torque between 2,000 and 2,500rpm.
Available in both RWD and xDrive versions, this smooth oil burner shoves you hard in the back on its way to 100km/h in 5.6 sec in rear drive form, or 5.4 sec with all-wheel-drive, yet overall consumption is a frugal best case 5.0 L/100km, with C02 emissions of just 132g/km.
I drove the xDrive version briefly on a rainy day in Portugal in December last year on the press launch of this latest G30 5-Series. But as I had to leave for the airport in short order I barely covered 20km in a model that I suspected at the time might just be the best overall 5-Series model on offer.
Fast forward to September this year, and I had the opportunity to put about 800km under the belt of a 530d in Germany, which meant I would have the opportunity to use the cars performance to the full on the autobahn. It also would give me the chance to assess its overall fuel consumption in real world conditions.