Debby Cunliffe
Jun 2025
Fantastic service. Came to my home on a Sunday to remap my car. Great job done and lifetime warranty plus interest free payment facility over 4 months available. Highly recommend
Posted on Google · view on our Google profileBMW 840i G14/G15/G16 ECU Remapping
BMW 840i G14/G15/G163.0 B58 · 2019–Present
Stage 1 £499
Get my quote →The BMW 840i G14/G15/G16 (2019 to Present) leaves the factory with 340 PS and 500 Nm from its 3.0 petrol engine. Our Stage 1 estimate takes it to 430 PS and 620 Nm, roughly 26% more power and 24% more torque.
BMW
ECU confirmed on inspection
840i
G14/G15/G16 · 3.0
Stage 1 estimate
430 PS
STX Tuning
Stage 1 price
£499
Stage 1 ECU remap
Estimated gain
+90 PS · +120 Nm
Power
Stock
340 PS
Stage 1
430 PS
Torque
Stock
500 Nm
Stage 1
620 Nm
Figures are STX Tuning estimates for a healthy standard car, not a dyno result for your vehicle. Power is shown in PS. These are existing vehicle library estimates, not independently measured results.
WhatsApp STX TuningWhat we do
More than just ECU remapping.
From Stage 1 and Stage 2 ECU remapping to gearbox tuning and supporting performance upgrades, STX Tuning offers specialist vehicle software and tuning services for compatible petrol and diesel cars and vans.
Explore the available options for your exact vehicle at our Slough workshop, with suitable mobile ECU remapping appointments available across selected surrounding areas.
- Stage 1 & Stage 2 ECU RemappingStage 1Stage 2
- Turbo Petrol ECU Tuning
- Turbo Diesel ECU Tuning
- Pops & Bangs
- Performance Remapping
- Economy ECU Remapping
Not sure which tuning service you need?
Tell us what you drive and what you'd like to achieve. We'll check your vehicle and help you explore the available options.
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