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Holley Efi Terminator X Max With Touchscreen - Gen 3 Gm Truck Engines

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Seize command of your LS engine with Terminator X Max! Reject mediocre salvage yard ECUs burdened with complex tuning interfaces. Opt for absolute engine control, self-learning fuel strategies, and the proven, race-winning technology of Holley EFI—all within a budget-friendly package!

Terminator X Max boasts real-time fuel learning, high-impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs. Tailored for electric fans, boost control solenoids, progressive nitrous control, and more. Part number 550-927 also includes 4L60E or 4L80E Transmission control and Drive-By-Wire Throttle Body control. Loaded with base maps for common LS engine combinations, Terminator X Max ensures a swift transition from the garage to the road/track fast. The 3.5" touch screen LCD handheld includes an easy-to-use calibration wizard, tuning, and gauge display functions. Also included is Holley EFI's industry-leading, user-friendly software suite for full laptop access for advanced users.

Whether you're crafting a budget-friendly cruiser or a boosted race car, Terminator X MAX delivers the features and technology you need at a price that won't break the bank!


  • For GM LS 4.8/5.3/6.0 Truck Engines with 24x crank reluctor, Transmission Control, Drive-by-Wire throttle body control, and Multec 2 Injectors.
  • Real-time fuel map learn removes guesswork from tuning your base fuel table.
  • High-impedance injector drivers safely power most stock LS injectors and Holley EFI Injectors (Does not control Low Impedance Injectors).
  • All Terminator X Max systems utilize the Bosch LSU 4.9 wideband to relay AFR information to the ECU for accurate reading and precise tuning control.
  • On-Board 1bar MAP sensor, perfect for N/A or Nitrous engine combos. For 2+Bar combinations, we recommend GM 12592525, and our adapter part number 558-416.
  • MAP Sensor vacuum hose adapters (1/8th – ¼ and 3/16ths).
  • 4 Inputs – 12v, Ground, 5v, and Frequency, for additional pressure sensors, or activation triggers for nitrous activation, or a trans brake.
  • 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 adjustable through included 3.5” full-color touchscreen; base tune easily created via handheld Wizard!
  • Advanced Tables – 4x 1D Tables, 1x 1D per Gear Table, 4x 2D Tables, 1x 2D per Gear Table, for custom tables like Flex Fuel Sensor Offset Table or a custom fuel or oil pressure safety!
  • On-Board Diagnostic LEDs for: ECU Power – Engine Run – Wideband Status – TPS Calibration – Crank Signal –Cam Signal. Identify any critical engine issues at a glance.
  • The included 3.5" Touchscreen Handheld contains a calibration wizard that allows you to quickly build a base tune for any LS engine. Additionally, the handheld provides internal data-logging and a fully customizable gauge display.
  • Compact ECU size allows you to mount it virtually anywhere. Remember, diagnostic LEDs must face up!
  • Plug and play compatible with more Holley EFI accessories such as analog-style gauges, shift lights, various modules, and coming soon, 12.3" digital dash support!
  • Free EFI Tuning Software for complete control of your Terminator X power plant.
  • Recommended Pedal part number - 10379038
  • Includes: 24x LS Engine Main Harness - Multec 2 Injector Harness - DBW Throttle Body Harness - 4L60E/4L80E Transmission Control Harness - Terminator X MAX ECU - ECU Main Power Harness - Bosch LSU 4.9 Wideband Oxygen Sensor - Input/Output Harness - and assorted.
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