| Weistec Horsepower | 952 |
| Weistec Torque | 720 |
| Manufacturer | Weistec |
| Street legal in all the US States | No |
| Engine Family | M840T |
| Stock Horsepower | 755 |
| See more | |
| year | make | model | trim | engine |
|---|---|---|---|---|
| 2021 | McLaren | 765LT | Spider | Twin Turbo 4L V8 (M840T) |
| 2020 | McLaren | 765LT | Base | Twin Turbo 4L V8 (M840T) |
| 2023 | McLaren | 765LT | Spider | Twin Turbo 4L V8 (M840T) |
| 2022 | McLaren | 765LT | Spider | Twin Turbo 4L V8 (M840T) |
| 2023 | McLaren | 765LT | Base | Twin Turbo 4L V8 (M840T) |
| 2022 | McLaren | 765LT | Base | Twin Turbo 4L V8 (M840T) |
| See more | ||||
Product Description
The 765LT is the most powerful Longtail McLaren has ever built, and it's carrying real history on its shoulders: a lineage that runs back to the F1 GTR Longtail race cars and, in modern road-car form, through the 675LT and 600LT before it. Built from the 720S, it takes the same factory-tuned M840T V8 all the way to 765PS, the number it's named after, while shedding weight and adding aerodynamics that McLaren says produce 25 percent more downforce than a standard 720S. McLaren built exactly 765 coupes worldwide, which makes this as much a numbered piece of McLaren history as it is a performance variant.
Weistec's calibration for the 765LT recalibrates that factory M840T software. It's built to extend what McLaren already engineered into this car, not compete with it. Every factory protection, from knock detection to thermal management to OEM diagnostic behavior, is preserved as-is. Delivered with OEM-level calibration rigor, it moves this 765LT from a factory 755 hp and 590 lb-ft to 952 hp and 720 lb-ft, taking the most extreme Longtail McLaren has ever built and finding even more in it.
How Do You Get Your 765LT 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.



