Skip to main content

Holley EFI Terminator X Max - LS1/LS6

Part # 550-929T
17 Reviews

24x Crank - 1x Cam - EV1 Injectors - Drive-By-Wire Throttle Body Control - USB/CAN Tuning Cable

Crank Reluctor

Drive-By-Wire

Handheld Included

Injector Connector

Transmission

Holley EFI Terminator X Max - LS1/LS6

Estimated Ship Date: 07/14/2025
Find Similar In-Stock Items
Free Shipping - Lower 48 US States
$1,789.95
Add to Wishlist
Notify Me When Available

Does it fit my engine?
3

Emissions

This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles.

See Emissions Details
Take control of your LS engine with Terminator X Max! Don't settle for a junkyard 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 Max features real-time fuel learn, high impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs. The inputs and outputs are ideal for electric fans, boost control solenoids, progressive nitrous control, and much more. Part number 550-929 also has Drive-by wire throttle body control. Terminator X Max comes fully loaded with base maps for common LS engine combinations to get you out of the garage and on the road/track fast. The These Terminator X kits include a USB/CAN tuning cable instead of the 3.5" Handheld LCD, these kits require the use of the free Terminator X Software for initial setup. The Terminator X Software includes multiple base calibrations to choose from for either naturally aspirated or boosted engines. 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 a budget beater or a boosted race car, Terminator X MAX has the features and technology you need at a price that won't break the bank!

Features:

  • For GM LS1/LS6 engines with 24x crank reluctor and a Drive-By-Wire Throttle Body, and EV1 Injectors
  • Real-Time fuel map learn, takes the guess work out of tuning your base fuel table.
  • High Impedance Injector Drivers will safely power most Stock LS injectors, and Holley EFI Injectors. Injector support chart provided in the instructions (Will not control Low Impedance Injectors)
  • All of the new 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, is perfect for N/A or Nitrous engine combos. If your combination requires a 2+Bar, 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 things such as 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
  • Advanced Tables – 4x 1D Tables, 1x 1D per Gear Table, 4x 2D Tables, 1x 2D per Gear Table, can be used for any custom tables you can dream up, such as 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. Allow you to identify any Critical engine issues at a glance
  • Includes CAN/USB tuning cable allowing you to configure your ECU and Tuning the engine in real time.
  • The compact ECU size allows you to mount it virtually anywhere. Remember, diagnostic LEDS must face up!
  • Plug and play compatible with multiple Holley EFI accessories including our gauges, shift lights, various modules, and digital and pro dashes (Holley P/N's 553-106, 553-111, and 553-112)
  • Free EFI Tuning Software for complete control of your Terminator X power plant
  • Recommended Pedal part number - 10379038
  • Includes: 24x LS Engine Main Harness - EV1 Injector Harness - DBW Throttle Body Harness - Terminator X MAX ECU - ECU Main Power Harness - Bosch LSU 4.9 Wideband Oxygen Sensor - Input/Output Harness - and assorted vacuum adapters.

About Holley EFI

Find standalone EFI for LS, Coyote, Hemi and more at Holley.com. From engine swapping to managing up to 4000 horsepower, we have a solution for every project!

Accelerometer SupportYes
Boost ControlYes
Brand Holley EFI
CAN-BUS SupportYes
CategoryAir and Fuel Delivery
Coil Per Cylinder Ignition SupportYes
Crank Reluctor24x
Datalogging SupportYes
Distributor IncludedNo
Drive-By-WireYes
Dry Nitrous ControlYes
e85 SupportYes
EGT SupportYes
Emission Code3
EngineGM LS1/LS2/LS6
Forced Induction SupportYes
Fuel Filter IncludedNo
Fuel Hose IncludedNo
Fuel Injectors IncludedNo
Fuel Pressure Regulator IncludedNo
Fuel Pump IncludedNo
Grade TypePerformance
Handheld IncludedNo
Idle Air Control Motor IncludedNo
Ignition Timing ControlYes
Ignition TypeGM LS 24x
Individual Cylinder Fuel CorrectionsYes
Injector ConnectorJetronic/Minitimer (Bosch EV1)
Intake Manifold IncludedNo
Knock Retard SupportYes
MAP Sensor1bar
Mounting Hardware IncludedNo
Multi-Stage Nitrous ControlYes
Part TypeFuel Injection System
Product TypeEFI System
Progressive Nitrous ControlYes
Self-TuningYes
Sub CategoryFuel Injection System and Related Components
Terminator LS OptionsFuel, Spark, Drive-by-Wire
Throttle Position Sensor IncludedNo
TransmissionNone
User-TuneableYes
Wet Nitrous ControlYes
UPC090127074596
Part Number550-929T
3

This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles.


The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles:

  • 1965 and older U.S. manufactured California Certified vehicles
  • 1967 and older U.S. manufactured Federally Certified vehicles
  • 1967 and older Foreign manufactured vehicle


WARNING: It is against the law to install this part on an Emissions Controlled Vehicle


The following vehicles are considered Emissions Controlled Vehicles:

  • 1966 and newer U.S. manufactured California Certified vehicles
  • 1968 and newer U.S. manufactured Federally Certified vehicles
  • 1968 and newer Foreign manufactured vehicle
Holley EFI Dealers
Do you need a custom kit built for your application? Do you need a system installed and tuned? Click here to find the Holley EFI dealer in your area!
Wiring Diagram
LS1 Main Harness
Terminator X ECU's are designed to be mounted with the LED's facing up. Designed to work with GM Throttle body P/N's - 12570790 and 12580760 Designed to work with GM Throttle Pedal P/N - 10379038. ECU is not recommended for marine applications, but can be used on off-road applications as long as you choose a safe location, keep it dry, protect from heat, and ensure proper wiring management.
Reviews
17

4.9 out of 5 stars

  • 5 star

    94%

  • 4 star

    6%

  • 3 star

    0%

  • 2 star

    0%

  • 1 star

    0%

Your Review

Items 1 - 17 of 17
  per page
Page:
  1. 1
Items 1 - 17 of 17
  per page
Page:
  1. 1

*Free Shipping and Handling only offered to the contiguous US on orders over $149, excludes clearance parts and oversized packages.

Some parts are not legal for use in California or other states with similar regulations.