| Weistec Horsepower | 730 |
| Weistec Torque | 652 |
| Manufacturer | Weistec |
| Street legal in all the US States | No |
| Engine Family | M838T |
| Stock Horsepower | 641 |
| See more | |
| year | make | model | trim | engine |
|---|---|---|---|---|
| 2016 | McLaren | 625C | Spider | Twin Turbo 3.8L V8 (M838T) |
| 2016 | McLaren | 625C | Base | Twin Turbo 3.8L V8 (M838T) |
| 2015 | McLaren | 625C | Spider | Twin Turbo 3.8L V8 (M838T) |
| 2015 | McLaren | 625C | Base | Twin Turbo 3.8L V8 (M838T) |
| 2017 | McLaren | 650S | Spider | Twin Turbo 3.8L V8 (M838T) |
| 2016 | McLaren | 650S | Spider | Twin Turbo 3.8L V8 (M838T) |
| See more | ||||
Product Description
The 650S is McLaren proving just how much more its own platform had to give. As the direct evolution of the 12C, it kept the same M838T V8 and MonoCell chassis but borrowed styling and aerodynamic thinking straight from the McLaren P1 hypercar, McLaren's own halo car at the time. Rather than starting over, McLaren pushed the existing 3.8-liter twin-turbo architecture as far as it would go without a clean-sheet redesign, and for a stretch it worked: the 650S briefly stood as the range-topping Super Series McLaren, ahead of even the 675LT and, later, the 720S.
Weistec's calibration for the 650S recalibrates that factory M838T's own software. It's built to extract more from engineering McLaren already validated, working with the platform instead of against it. Every factory safety net, knock protection and thermal management included, stays exactly where McLaren put it. Calibrated with the same rigor as an OEM software program, it takes the 650S from a factory 641 hp and 500 lb-ft to 730 hp and 652 lb-ft, turning a car that was already McLaren's best answer to its own platform into something genuinely next-level.
How Do You Get Your 650s ECU Tune Tuned?
Follow these steps — this is what your specific vehicle needs and supports.
Choose Your Tune Stage
Core Improvements
Standard with this tuneFree Add Ons
Pick Your Tuning Method

Cypher Plus
Order a Cypher Plus and tune your car yourself from your phone, entirely through the MyFlasher app. Watch how it works.

Mail It In
Remove your ECU or TCU and mail it to us for tuning. Required for some applications.

In Person
Bring your vehicle, or just your ECU/TCU, to our Anaheim, CA headquarters. Call 714-202-0005 or email sales@weistec.com to schedule.

Cypher Pro Dealer
Visit a certified Cypher Pro Dealer near you. Find one with our dealer locator.
Complete The Upgrade
An ECU tune alone won't remove all factory limits or fix how power reaches the ground. Add these to round out the upgrade with no limitations.
Read the full CPC & TCU breakdown →
What is a CPC module?
The CPC (Central Powertrain Control) is a separate control unit that manages things like the active exhaust valves, radiator fan, intercooler pumps, and speed limiter. On many newer Mercedes-Benz vehicles, it also houses torque limiters that can hold back an ECU tune from reaching its full potential.
What is a TCU tune?
A TCU (transmission control unit) tune delivers faster, firmer shifts with higher line pressure, reducing clutch slip and increasing the transmission's torque capacity. It's a worthwhile upgrade on its own, or paired with an ECU tune for a fully sorted powertrain.
Good to Know
- This is a reflash of your original module, not a stand-alone unit.
- Power gains vary by vehicle, modifications, fuel, and operating conditions (ambient temperature, altitude, etc.).
- New or upgraded spark plugs are always recommended when tuning.
- Product may not be emissions compliant. Check local laws prior to installation.
- Always use a battery charger during programming.
Fitment not confirmed
This part is not confirmed to fit your selected vehicle.




