Expert

BMW M57N2 306D3 Twin-Turbo Diesel Swap

Donor: BMW M57N2 306D3 (E90 335d / E70 X5 3.0sd)

The gold-standard modern diesel swap for the classic Defender. 286bhp / 580Nm from a proven BMW M57N2 twin-turbo six, mated to the ZF 6HP26 auto via an LT230 adapter. Delivers modern motorway cruising with legendary Land Rover low-range.

ECU Solution

House of Torque DDE6.3 standalone loom, or SpeedTech M57 kit

Gearbox Options

ZF 6HP26 auto with LT230 adapter (Ashcroft/Traxide) or R380/LT77 manual with Wabco adapter

Compatible Models

Defender 90 · Defender 110 · Defender 130

Critical Notes

Requires standalone DDE6.3 ECU (House of Torque or SpeedTech), custom prop shafts, and mandatory swirl-flap delete. Budget 200+ hours build time.

Step-by-step guide

10 steps

Step 1 of 10

Strip original engine and gearbox

01
Step
01
Info 2 days
Strip original engine and gearbox
Remove the existing Tdi/Td5/Puma engine, gearbox, prop shafts, radiator, fuel lines and loom. Photograph everything before disconnecting.
Tools
Engine crane, 19mm/17mm/13mm sockets, Trolley jack
Parts
Engine stand, Storage crates
02
Step
02
Caution 1 day
Fabricate M57 engine mounts
Weld or bolt in M57-specific mounts (House of Torque or Nene Overland kit). Verify sump clearance over the front diff — Defender 110 needs a modified sump.
Tools
MIG welder, Angle grinder, Level
Parts
M57 mount kit, Modified sump
03
Step
03
Caution 1 day
Mate ZF 6HP26 to LT230
Bolt the ZF 6HP26 to the LT230 transfer box using the Ashcroft or Traxide adapter plate. Fit the correct input shaft and torque converter.
Tools
Torque wrench, Alignment dowels
Parts
Ashcroft ZF-LT230 adapter, Input shaft, Torque converter
04
Step
04
Critical 3 hours
Perform swirl-flap delete
CRITICAL — remove the intake manifold and install aluminium blanking plates over all six swirl-flap ports. Failure of the plastic flaps destroys the engine.
Tools
T30 Torx, Torque wrench
Parts
Swirl-flap blanking kit, New manifold gasket
05
Step
05
Critical 2 days
Install DDE6.3 standalone loom
Fit the House of Torque DDE6.3 loom. Route the CAN bus cleanly, fuse the main power feed at the battery, and mount the DDE box in the cabin behind the dash.
Tools
Multimeter, Crimper, Heat gun
Parts
House of Torque DDE6.3 loom, Fuse box, Relays
06
Step
06
Caution 1 day
Fabricate exhaust and intercooler pipework
Route the 2.5" downpipe past the steering box, over the front axle to the transmission tunnel. Fit a front-mount intercooler with silicone couplers.
Tools
Pipe bender, MIG welder, Silicone hose clamps
Parts
Custom downpipe, Front-mount intercooler, Silicone piping, V-band clamps
07
Step
07
Info 4 hours
Fit cooling system
Install an uprated Allisport or Nissens aluminium radiator with dual electric fans. Route heater matrix pipes to the M57 water outlet.
Tools
Screwdrivers, Coolant funnel
Parts
Allisport radiator, Twin 12" fans, Silicone hoses
08
Step
08
Critical 5 hours
Fuel system — high-pressure return
M57 needs 5-bar low-pressure feed to the CP3 pump. Fit a Bosch inline lift pump, 10-micron filter, and return line back to the tank.
Tools
Flare tool, Cutter
Parts
Bosch 044 pump, 10-micron filter, 8mm return line
09
Step
09
Caution 1 day
Custom prop shafts and axle checks
Measure and order new front + rear prop shafts (GKN or Traxide). Confirm your rear diff can handle 580Nm — Ashcroft ATB recommended.
Tools
Tape measure, Torque wrench
Parts
Custom prop shafts, Ashcroft ATB (optional)
10
Step
10
Critical 1 day
Commissioning and remap
Prime the fuel system, crank without injectors to build oil pressure, then start. Book a rolling-road session with a BMW-specialist tuner (Darkside, ProTuning Freaks) for a custom map.
Tools
OBD dongle, Coolant refractometer
Parts
Fresh oil (5W-30 LL04), Coolant, Diesel

House of Torque · M57 Conversion Parts

12 items · GBP ex-VAT

Curated single-source list from House of Torque — the reference supplier for M57 swap adapters, mounts, standalone looms and DDE ECUs. Prices are indicative UK trade (ex-VAT and shipping); confirm on the product page before ordering. Not affiliated.

System	Part	Price	Source
Mounting	Mount Kit — M57N2 + ZF Auto to TDCI chassis Bolt-in engine + gearbox mount kit for RHD Defender TDCI chassis. Pairs with the 6/8HP to LT230 adapter. · Only 2 left	£320	View at HoT →
Mounting	Mount Kit — M57N + ZF Auto to TDCI chassis For M57N (single-turbo) donors. Same TDCI chassis fitment as the N2 kit.	£320	View at HoT →
Mounting	Pre-Puma Engine Mounts M57 engine mounts for Td5 / 300Tdi chassis (pre-2007 Puma).	£110	View at HoT →
Mounting	Pre-Puma Bolt-in LT230 Mounts LT230 transfer-case mounts for pre-Puma chassis. Pairs with the pre-Puma engine mount set.	£130	View at HoT →
Driveline	6/8HP ZF to LT230 Adapter Kit Mates BMW ZF 6HP26X / 6HP28X / 8HP70X to Land Rover LT230 transfer case. Includes spigot and input shaft. · In stock	£830	View at HoT →
ECU / Loom	DDE 5/6 EDC16 Standalone Wiring Harness Standalone loom for DDE5 / DDE6 EDC16 ECUs — removes BMW body-CAN dependencies.	£200	View at HoT →
ECU / Loom	DDE 5/6 Standalone Harness (TDCI Pedal Plug) Same DDE5/6 standalone loom with a Puma TDCI throttle-pedal plug pre-fitted. Currently on sale. · Backorder OK	Sale — POA	View at HoT →
ECU / Loom	M57 204 Euro 3 DDE ECU Pre-programmed Euro-3 DDE for 204 bhp M57N donors. Immobiliser delete applied.	£280	View at HoT →
ECU / Loom	M57 204 Euro 4 DDE ECU Pre-programmed Euro-4 DDE for 204 bhp M57N donors. Immobiliser delete applied.	£400	View at HoT →
ECU / Loom	Immobiliser / EWS Delete Service Send-in service — HoT flashes your existing DDE to remove CAS/EWS handshake.	£135	View at HoT →
Cooling	Defender Aluminium Radiator + Intercooler Package Uprated ally rad and front-mount intercooler sized for M57 heat load. Bolts to Defender front panel.	£700	View at HoT →
Induction	M57 Aluminium Inlet Manifold Cast-ally replacement for the plastic OE manifold — eliminates the common cracked-runner failure. · Check availability	£250	View at HoT →