Product Summary

Universal Fit, Factory GM Ignition Type

    Key Specs

    MFG. Part #550-1631LSD
    Ignition TypeFactory GM
    Tuner StyleTouchscreen Handheld
    Throttle StyleDrive-By-Wire

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    Holley 550-1631LSD Details


    with GM LS Drive-by-Wire Throttle Body Control and GM 4L60 and 4L80 Transmission Control

    Take control of your GM Gen V LT1, L83, or L86 engine with Terminator X! Do not settle for a factory ECU with a cumbersome tuning interface when you can have complete control of your engine, self-learning fuel strategies and the proven, race-winning technology of Holley EFI at a budget-friendly price! Terminator X features real-time fuel learn, an integrated 1bar MAP sensor, and four programmable inputs and outputs. The inputs and outputs are ideal for electric fans, boost control solenoids, progressive nitrous control, and much more. Terminator X comes fully loaded with base maps for common LT engine combinations to get you out of the garage and on the road/track fast. The 3.5" touch screen LCD handheld contains an easy to use calibration wizard as well as tuning and gauge display functions. All Gen V LT Terminator X kits will come with an external Gasoline Direct Injection Controller, which enables the end user to control and tune, factory injectors, GM Gen V LT Variable Valve Timing (VVT), and factory fuel pumps. Also included is Holley EFI's industry-leading, easy to use software suite that allows full laptop access for advanced users. Whether you are building, an LT swapped budget beater or a boosted racecar, Terminator X has the features and technology you need at a price that will not break the bank!

    To identify if your engine is an early or late application, refer to your fuel pressure sensor, located behind the intake manifold. Early sensors have a 4-pin connector, whereas late sensors have a 3-pin connector. This will help you pick which kit you require for your engine.


  • Plug and play GM Gen V LT engine control including GDI and VVT support
  • Ideal for swapping late model GM Gen V LT engines into vintage vehicles
  • 3.5 handheld gets your engine running in no time with a step-by-step calibration wizard
  • GM LS and LT Drive-by Wire Throttle Body Control (Terminator X Max Only)
  • GM 4L60 and 4L80 Transmission Control (Terminator X Max Only)
  • Included engine harness plugs directly into the factory LT DI injector sub harness
  • OEM Injectors supported, with part numbers provided in the handheld wizard, or software
  • Genuine Bosch LSU 4.9 Wideband Control (Will not work with LSU 4.2 Oxygen Sensors) Genuine Bosch LSU 4.9 Wideband Control (Will not work with LSU 4.2 Oxygen Sensors)
  • On-Board Diagnostic LEDS for: ECU Power Engine Run Wideband Status TPS Calibration Crank Signal Cam Signal VVT Status Pump Control and DI Injectors. Allowing you to identify any Critical engine issues at a glance
  • Built in 1bar MAP Sensor, vacuum hose adapters included (1/8th ¼ and 3/16ths) - or for Boosted applications, you can disable the internal MAP sensor, and utilize an external LT MAP Sensor, the harness comes with the connector terminated, making the inst
  • 4 Inputs 12v, Ground, 5v, and Frequency, for things such as additional pressure sensors, or activation triggers for nitrous activation, or a trans brake (Fuel and Oil Pressure Inputs are pre-terminated)
  • 4 Outputs Ground, PWM - , for accessories such as; fans, boost control, nitrous control, IAC Kit, and more
  • Boost Control Boost vs Time, Boost vs Gear, Boost vs RPM, Boost vs Speed, Boost Safeties
  • Nitrous Control Single Channel of Wet or Dry, Progressive or Non-Progressive, Rich/Lean Safeties, and target Closed Loop AFR
  • Advanced Tables 4x 1D Tables, 1x 1D per Gear Table, 4x 2D Tables, 1x 2D per Gear Table
  • Integrated data logging to the 3.5 Handheld SD Card
  • Free EFI Tuning Software for complete control of your Terminator X power plant
  • Charts

    CARB Warning

    For race/ off road use or for use on pre-1966 vehicles.

    Emissions warning: this part only legal for sale or use in California for racing (competition) vehicles which may never be used, registered, or licensed for use upon a public highway, or if installed in vehicles model-year 1965 or older; motorcycles model-year 1977 or older; or off-highway recreational vehicles (such as off-road motorcycles and all-terrain vehicles) model-year 1996 and older. Any other use renders the vehicle tampered and not legal for use on California public highways (any public street or roadway, public dirt road, public park, or publicly maintained right of way open to the use of the public for vehicular travel). Violations subject to $37,500 penalty per violation per vehicle, revocation of registration, loss of use on California public right of ways, and proof of correction for tampering. There are similar restrictions and penalties under federal law and the laws of all other states with penalties under federal law of up to approximately $45,268 per tampered vehicle and/or engine.

    Holley 550-1631LSD Specifications

    MFG. Part #550-1631LSD
    Ignition TypeFactory GM
    Tuner StyleTouchscreen Handheld
    Throttle StyleDrive-By-Wire
    Injector ConnectorOEM
    MAP Sensor IncludedYes
    Transmission ControlYes
    Oxygen Sensor StyleBosch
    GTIN Code090127101995
    Sold in QuantityKit