The BMW M47 was a family of 2.0-litre turbo-diesel engines that were available from 1999 to 2007. The M47 was replaced by BMW’s N47 engine.
M47D20
Available from 1999, the M47D20 engine had a cast iron block, an alloy cylinder head, indirect injection (i.e. not common rail), a forged steel crankshaft, double overhead camshafts (chain-driven), four valves per cylinder and exhaust gas recirculation. The M47D20 engine had one swirl and one tangential intake port per cylinder, though swirl flaps were introduced until the M47TUD20.
M47TUD20
For the M47TUD20, changes included:
- An increase in capacity to 1995 cc (from 1951 cc);
- The introduction of a second-generation common-rail injection system;
- Fitment of a variable geometry turbocharger;
- DDE5 (Digital Diesel Electronics 5) engine management; and,
- Introduction of swirl flaps (see further, below).
M47TU2D20
Available from 2004, the M47TU2 engines increased power to 90kW and 120kW for the standard and high output variants. For M47TU2 engines that were mated to automatic transmissions, the drivetrain had a higher mechanical power loss rate such that the engine was driven under higher load. Because this had a negative effect on emissions, models with automatic transmissions were fitted with a particulate trap catalytic converter. The particulate trap catalytic converter had a stainless steel housing which it shared with the oxidation catalytic converter. In contrast to the diesel particulate filter, the particulate trap catalytic converter was designed as a separator system with no sensors.
| Engine | Capacity | Peak power | Peak torque | Models | Years |
|---|---|---|---|---|---|
| M47D20 | 1951 cc | 100kW at 4000rpm | 280Nm at 1750rpm | E46 320d | 1999-01 |
| E39 520d | 2000-03 | ||||
| 85kW at 4000rpm | 265Nm at 1750rpm | E46 318d | 2001-03 | ||
| M47TUD20 | 1995 cc | 85kW at 4000rpm | 280Nm at 1750rpm | E46 318d | 2003-05 |
| 110kW at 4000rpm | 330Nm at 2000-2500rpm | E46 320d | 2001-05 | ||
| E83 X3 2.0d | 2001-06 | ||||
| M47TU2D20 | 1995 cc | 90kW at 4000rpm | 280Nm at 2000rpm | E87 118d | 2004-07 |
| 90kW at 4000rpm | 280Nm at 1750-2000rpm | E90 318d, E91 318d |
2005-07 | ||
| 120kW at 4000rpm | 340Nm at 2000-2750rpm | E87 120d | 2004-07 | ||
| E90 320d, E91 320d |
2005-07 | ||||
| E83 X3 2.0d | 2006-07 | ||||
| E60 520d | 2005-07 |
M47 swirl flaps
In the 2.0-litre M47TUD20 and M47TU2D20 turbo-diesel engines, the swirl flap mechanism in the inlet manifold consisted of butterfly valves within each individual inlet tract. These butterfly valves were secured to an actuating rod via two small screws and, over time, these screws could become loose. If this occurred, the screws could be drawn into the cylinder and cause significant damage to the piston, cylinder head and valves. If a screw were to pass through the exhaust valve, it could then damage the turbocharger. As a result of this problem, a common modification is to remove the swirl flaps and replace them with blanking plates. From 2004 to 2007, BMW introduced larger diameter spindles (made from plastic) and larger screws, though these engines were not immune to failure. Around 2006, it is understood that plastic swirl flaps were introduced to reduce the likely extent of damage.
