| Weistec Horsepower | 730 |
| Weistec Torque | 652 |
| Manufacturer | Weistec |
| Street legal in all the US States | No |
| Engine Family | M838T |
| Stock Horsepower | 625 |
| See more | |
| year | make | model | trim | engine |
|---|---|---|---|---|
| 2014 | McLaren | MP4-12C | Spider | Twin Turbo 3.8L V8 (M838T) |
| 2014 | McLaren | MP4-12C | Base | Twin Turbo 3.8L V8 (M838T) |
| 2013 | McLaren | MP4-12C | Spider | Twin Turbo 3.8L V8 (M838T) |
| 2013 | McLaren | MP4-12C | Base | Twin Turbo 3.8L V8 (M838T) |
| 2012 | McLaren | MP4-12C | Base | Twin Turbo 3.8L V8 (M838T) |
Product Description
The MP4-12C is the car that brought McLaren back. It was the first all-new production McLaren built since the legendary F1 left showrooms, and the first car ever to wear the newly formed McLaren Automotive badge, which is a huge amount of history riding on one engine bay. That engine, the 3.8-liter M838T, is a genuinely special piece of engineering: a 90-degree, flat-plane-crank twin-turbo V8 developed with the UK's Ricardo, whose cylinder bore can be traced all the way back to a Nissan-derived block that TWR originally built for an IndyCar program that never even got to race. McLaren clearly believed in what they'd built, because they didn't sit still with it, bumping factory output from 592 PS to 625 PS and wrapping it all in the carbon-fiber MonoCell chassis that became the template every McLaren since has been built around.
Weistec's ECU calibration takes that already remarkable M838T and pushes it further, working entirely within the engine's own software architecture rather than bolting anything on top of it. Every factory protection McLaren engineered in, from knock detection to thermal management to OEM diagnostics, stays fully active and untouched. It's an OEM-level recalibration, built with the same rigor as a factory engineering program, and on the MP4-12C that means real numbers: a jump from 625 hp and 443 lb-ft to 730 hp and 652 lb-ft. This was the car that put McLaren back on the map. With Weistec's calibration behind it, it's operating on a whole different level.
How Do You Get Your MP4 12C 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.



