A Short History
From January 1999, the Land Rover Defender range was fitted with the new Td5 diesel engine for most markets. The Discovery Series II was fitted with the Td5 from launch, also in January 1999.
The five cylinder direct injection turbo diesel intercooled engine was a design started by Rover Group in 1993 as
part of their development of a range of 4, 5, and 6 cylinder diesel engines (of 2, 2.5 and 3 litres respectively) to meet all Rover and Land Rover diesel engine requirements.This new range of engines (codenamed Storm project) was loosely based upon the L-series 4 cylinder engine, at that time used in the Freelander and various Rover cars.
When BMW bought Rover Group in 1994, the Storm project was already underway and the 5-cylinder project's continuation was approved, to replace the Tdi in the Discovery and Defender. This was the only project to make it in to production however which is a shame as a 6 cylinder, 3L version in a 90 would be something else.
Offering more power and greater refinement than the 300Tdi the Td5 greatly improved the appeal of the
Discovery but caused concern amongst many operators of the Defender due to its electronic engine management systems.
The Td5 was the first diesel engine in the Defender to be wholly controlled by an engine management (or control)
unit (EMU/ECU) - codenamed 'Thunder' and developed in conjunction with Lucas. The ECU regulates fuel delivery by
taking into account a number of factors from the engine and the surroundings - such as inlet air pressure and
temperature, intake air flow, coolant temperature and the throttle pedal position from the fly-by-wire accelerator. The ECU improves drivability by taking inputs from the clutch, brake and throttle pedal to smooth out gear changes and reduce driveline shunt. With low range selected, the ECU enables Fast Throttle Control (FTC) which widens pedal travel, giving more control over the engine speed in off road and low speed operation.
Despite concerns, time has shown that the Td5's electronics are reliable. Early engines suffered two isolated mechanical failures—sudden and complete failure of the oil pump drive (due to the oil pump sprocket bolt not being locktighted in place during assembly) and 'cylinder head shuffle' caused by weak retaining studs. Both these faults were fixed within 2 years of the engine starting production and the Td5 is now considered highly reliable. In 2002 the Td5's electronics were updated to improve the low-speed throttle response which had been prone to producing a jerky power delivery in off-road or towing situations. The engine has proved itself on numerous expeditions in hostile terrain (including Land Rover's own G4 Challenge). The engine's mechanical strength and electronic control systems makes the Td5 much more tuneable than the older engines.
Why Choose A Td5?
My last Defender was a 300 Tdi, and when I decided to buy another Defender, it was another 300 Tdi that I had decided to buy. However, the 300 Tdi hasn't been produced for a number of years now and finding a good, unmolested, unmodified vehicle for a sensible price isn't that easy. I started looking at the Td5 as an alternative.
Browse any Land Rover or 4X4 forum or message board and you will probably find numerous posts detailing how a Td5 is overly complex, not user friendly to the home mechanic, prone to electronic failure, prone to stalling and absolutely gutless at low revs. The ease of tuning however, and the power gains available was appealing, so a Td5 was decided on as the powerplant of choice for my next Defender and eventually picked up and early (1999) Td5 hardtop. So, now I own one whats my opinion of it?
After spending a large period of time on message boards etc reading as much about the Td5 as I could before buying, I was expecting a vehicle that would stall at the drop of an hat and would need lots of revs to actually do anything. So much so I was planning on getting it remapped almost as soon as I got one. After owning one however, I'm pleased to say that neither of these two assertions is actually true and a lot of stuff regarding the Td5 posted on the internet is urban legend. Yes, it is slightly easier to stall a Td5 than a Tdi when pulling away, but that is more due to the slight delay in the fly by wire accelerator reacting than any deficiency in torque or power. To get around this, either push the accelerator fractionally sooner so the revs are rising as you bring the clutch up or, do the complete opposite and don't use the accelerator at all and let the anti-stall sort it out. Slightly different driving style is all it amounts too. As for the Td5 being gutless at low revs, I haven't found it to be. At 1400rpm it's already churning out more torque than my previous Tdi's maximum torque at 1800rpm. In fact, I've found most obstacles and climbs can be done using 3rd gear low range with no throttle input at all, just let the anti-stall trickle in just enough revs to keep it moving.
Browse any Land Rover or 4X4 forum or message board and you will probably find numerous posts detailing how a Td5 is overly complex, not user friendly to the home mechanic, prone to electronic failure, prone to stalling and absolutely gutless at low revs. The ease of tuning however, and the power gains available was appealing, so a Td5 was decided on as the powerplant of choice for my next Defender and eventually picked up and early (1999) Td5 hardtop. So, now I own one whats my opinion of it?
After spending a large period of time on message boards etc reading as much about the Td5 as I could before buying, I was expecting a vehicle that would stall at the drop of an hat and would need lots of revs to actually do anything. So much so I was planning on getting it remapped almost as soon as I got one. After owning one however, I'm pleased to say that neither of these two assertions is actually true and a lot of stuff regarding the Td5 posted on the internet is urban legend. Yes, it is slightly easier to stall a Td5 than a Tdi when pulling away, but that is more due to the slight delay in the fly by wire accelerator reacting than any deficiency in torque or power. To get around this, either push the accelerator fractionally sooner so the revs are rising as you bring the clutch up or, do the complete opposite and don't use the accelerator at all and let the anti-stall sort it out. Slightly different driving style is all it amounts too. As for the Td5 being gutless at low revs, I haven't found it to be. At 1400rpm it's already churning out more torque than my previous Tdi's maximum torque at 1800rpm. In fact, I've found most obstacles and climbs can be done using 3rd gear low range with no throttle input at all, just let the anti-stall trickle in just enough revs to keep it moving.
Td5 Torque & Power Graph.
While the Td5 has an ECU, it's still a relatively simple vehicle in modern terms. I loved both my 300 Tdi, and the 200 Tdi that went before it, both performed very well and did everything asked of them, but neither put quite as big a smile on my face as the Td5 does. I may still get it remapped at some point in the future but for now, I'm quite satisfied with how the standard unit performs. I like it a lot.
Anyone wishing to join a forum/message board with good information of the Td5, I would recommend this one below.
Anyone wishing to join a forum/message board with good information of the Td5, I would recommend this one below.
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