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ENGINEERING THE FUTURE OF PERFORMANCE ™
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765LT ECU Tune
Purchase 765LT ECU Tune
  • SKU: 765LT-ECU-Tune

    765LT ECU Tune

  • Advertised gains are estimates of HP and Torque “at the engine” calculated from gains as measured on a Dynojet Dynamometer in ideal conditions and typically show the largest possible change.  Actual gains are dependent on the following: Learn More about Crank HP Vs Wheel HP

    Model – Manufacturers use the same engine in multiple model vehicles and often times they are in a different state of tune, for example: 2008 C63 and a 2008 CLK Black Series.  Both have the same engine, but the C63 has 451hp while the CLK63 has 500hp.  Naturally the C63 will show more gains as it starts at a lower level.

    Model Year – Similar to above, as time progresses, Manufacturers tend to slightly increase power output via software from one year to the next or offer “Performance Packages” with increased power.  The engines remain largely unaltered and as a result, final tuned output remains the same, while the gains are lower as the starting point is now higher.

    Fuel – Fuel quality is HIGHLY important with performance vehicles.  Low quality and/or low octane fuel will greatly impact engine output and potentially even engine health.  Top tier brand premium fuels should always be used to achieve the best results possible.

    Drivetrain – All wheel drive has higher drivetrain losses than rear wheel drive.  This results in lower numbers when testing on a chassis dyno.  Wheel/tire size and weight will also impact chassis dyno results

    Weather/Conditions – Temperature, humidity, altitude, and air density all impact engine performance.  Heat, high humidity, and thin air will all work towards reducing engine output

    Engine Health – Higher miles tends to result in increased build up and lower compression which can and will impact engine output.  Properly maintained engines will have better performance than abused or neglected engines.

    Supporting modifications – The highest power levels require supporting modifications.  Depending on the engine, this could mean forged internals, built transmission, upgraded fuel system, 110+ octane race fuel, etc.

  • Stage:
  • $5,499.00 $5,499.00

  • Prop 65 warning
    Warning

    This product can expose you to chemicals including carbon black, silica - crystalline, formaldehyde, and lead which are known to the State of California to cause cancer, and lead, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

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.

2

Choose Your Tune Stage

3

Core Improvements

Standard with this tune
  • Increased Horsepower
  • Increased Torque
  • Improved Throttle Response
  • Optimized Fuel and Spark
  • Increased Boost
  • Top Speed Limiter Removed
4

Free Add Ons

Want it louder?

Read more about Burble & Pops →

This tune can have Burble/Pops added or increased on deceleration, at no additional charge. Select an intensity below and we'll add it to your order, or mention it when requesting your tune — through the Cypher+ app, your calibration request form, or when placing your order.

Want to stop the stopping?

Read more about Auto Start-Stop →

Auto Start-Stop can be turned off as part of your ECU tune alone, at no additional charge. Just mention it when requesting your tune — through the Cypher+ app, your calibration request form, or when placing your order.

5

Pick Your Tuning Method

See the full tuning process →
1Selected

Cypher Plus

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

2Selected — Pick return shipping at checkout

Mail It In

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

3Selected — Pick Will call at checkout

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.

4Selected — Order through your local dealer

Cypher Pro Dealer

Visit a certified Cypher Pro Dealer near you. Find one with our dealer locator.

6

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.

Your Total  

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.