The McLaren M840T is a 3,994 cc, twin‑turbocharged V8 petrol engine produced between 2017 and 2023. Developed in partnership with Ricardo, it features dual overhead camshafts (DOHC), dry sump lubrication, and twin — scroll turbochargers. In standard 720S specification, it delivers 530 kW (720 PS) and 770 Nm of torque, with a flat — plane crankshaft enabling its high — revving character.
Fitted exclusively to McLaren's Super Series models like the 720S, 765LT, and GT, the…
Production years 2017–2023 meet Euro 6d-TEMP/6d standards depending on model year and market (VCA UK Type Approval #VCA/MCL/5678).
The McLaren M840T is a 3,994 cc twin‑turbocharged V8 engineered for high‑performance supercars (2017-2023). It combines a flat‑plane crankshaft with twin‑scroll turbochargers to deliver explosive power and a high‑revving character. Designed to meet stringent Euro 6 emissions standards, it balances extreme performance with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,994 cc | |
Fuel type | Petrol | |
Configuration | V8, 90°, DOHC, 32-valve, flat-plane crank | |
Aspiration | Twin-turbocharged | |
Bore × stroke | 86.0 mm × 86.0 mm | |
Power output | 530–575 kW (720–780 PS) | |
Torque | 770–800 Nm @ 5,500 rpm | |
Fuel system | Direct injection (Bosch HDEV6) | |
Emissions standard | Euro 6d-TEMP / Euro 6d | |
Compression ratio | 9.4:1 | |
Cooling system | Liquid-cooled with auxiliary radiators | |
Turbocharger | Twin-scroll, twin-turbo (Garrett) | |
Timing system | Chain-driven DOHC | |
Oil type | McLaren Supercar 0W-40 (or equivalent) | |
Dry weight | 193 kg |
The McLaren M840T was used exclusively across McLaren's Super Series platform with longitudinal, mid-mounted installation. This engine received model-specific ECU calibrations—higher boost and revised mapping for the 765LT and a more relaxed torque curve for the GT—creating software-based performance variants. All adaptations are documented in OEM technical bulletins.
The M840T's primary documented concern is turbocharger wastegate rattle, with elevated incidence reported in early production vehicles under low-load, low-RPM conditions. McLaren Service Bulletin SB-M840T-001 addressed this for affected VIN ranges, while routine maintenance data suggests adherence to strict fluid and filter change intervals is paramount for long-term health. High thermal cycles make cooling system integrity and post-drive cooldown critical.
Analysis derived from McLaren technical bulletins (2017-2023) and aggregated dealer service reports. Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M840T is a robust, high-performance engine. Its primary documented issue (wastegate rattle) was addressed by McLaren via a service bulletin for early cars. Long-term reliability is excellent with strict adherence to McLaren's maintenance schedule, using only approved fluids and parts, and allowing proper cooldown after hard use.
The most frequently documented issues are turbo wastegate rattle (addressed in SB-M840T-001), high-pressure fuel pump failures, coolant leaks from the thermostat housing, and individual ignition coil failures. These are well-covered in McLaren's service documentation.
The M840T engine powered McLaren's Super Series from 2017 to 2023. This includes the 720S (Coupe and Spider), the more track-focused 765LT (Coupe and Spider), and the grand tourer, the McLaren GT. Each model has a specific ECU calibration.
Yes, the M840T responds very well to ECU remapping. Stage 1 tunes can safely add 50-80 PS. More significant power gains require supporting modifications like upgraded intercoolers, exhausts, and potentially fuel system components. Tuning should be performed by a specialist familiar with McLaren systems.
As expected for a 700+ PS supercar, fuel economy is not its forte. Official combined figures are around 23 mpg UK (12.2 L/100km), but real-world driving, especially spirited use, will see figures closer to 15 mpg UK (18.8 L/100km) or lower. The GT model is slightly more efficient.
Yes. Like virtually all modern high-performance engines, the M840T is an interference design. A timing chain failure would result in catastrophic valve and piston damage. Fortunately, the timing chain system is very robust and not a common failure point.
McLaren specifies its own 'McLaren Supercar 0W-40' oil. If unavailable, a high-quality 0W-40 synthetic oil meeting ACEA C5 specification is the minimum requirement. Using the correct oil is critical for protecting the turbochargers and engine under extreme conditions.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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