Product Summary

Universal Fit, 24x Crank Reluctor, 1x Cam Trigger

  • Kit will provide you with complete control of your engine, self-learning fuel strategies and the proven, race-winning technology of Holley EFI
  • Features real-time fuel learn, cable driven, high impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs
  • 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 LS engine combinations to get you out of the garage and on the road/track fast
  • A 3.5" touch screen LCD handheld contains an easy to use calibration wizard as well as tuning and gauge display functions
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Key Specs

MFG. Part #550-904
Ignition TypeFactory GM
Injector ConnectorMultec 2
Tuner StyleTouchscreen Handheld
Throttle StyleCable Driven
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Need To Know

Quick and Easy Returns

Return Policy

Holley 550-904 Details

Take control of your LS engine with Terminator X! 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 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. Terminator X 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 3.5" touch screen LCD handheld contains an easy to use calibration wizard as well as tuning and gauge display functions. 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 has the features and technology you need at a price that won't break the bank!

Features

  • For GM LS Engines with 24x crank reluctor and Multec 2 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 systems utilize the Bosch LSU 4.9 wideband to relay AFR information to the ECU for accurate reading and precise tuning control.
  • MAP Sensor vacuum hose adapters (1/8th – ¼ and 3/16ths)
  • 4 Outputs – Ground, PWM - , for accessories such as; fans, boost control, nitrous control, IAC Kit, and More
  • 4 Inputs – 12v, Ground, 5v, and Frequency, for things such as additional pressure sensors, or activation triggers for nitrous activation, or a trans brake
  • 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
  • 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
  • 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!adjustable through included 3.5” f
  • 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.
  • The 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

Application

For GM LS Engines with 24x crank reluctor and Multec 2 Injectors.

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 550-904 Specifications

KEY SPECS
MFG. Part #550-904
BrandHolley
Ignition TypeFactory GM
Injector ConnectorMultec 2
Tuner StyleTouchscreen Handheld
Throttle StyleCable Driven
GENERAL
Crank Reluctor24x
Cam Trigger1x
MAP Sensor IncludedYes
Transmission ControlNo
Oxygen Sensor StyleBosch
GTIN Code090127060803
Sold in QuantityKit

Ratings & Reviews

5

3 Reviews

Overall Assessment

Customers have highlighted the product's excellent quality and practicality, particularly for 5.3 builds. Its superior usability and performance are consistently praised, setting it apart from competitors. While some users have yet to install it, recommendations based on friends' positive experiences reinforce its perceived value. Notably, customers would willingly repurchase due to its proven capabilities and competitive price point.

5

3 reviews

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Filter by Ratings

Extremely well put together kit. Would recommend to anyone!

5.0

2 years ago

Mike

WA

Verified

1978 280z with LS1 swap. The harness comes with plenty of wire to tuck or go around the plenum. Extremely easy setup.

Would Recommend

This product is great me and my buddy both love it in the5.3

5.0

3 years ago

Reese

Owensboro Kentucky

Verified

Works great with the 5.3 build that I have going on right now love the product

Would Recommend

I would definitely order from speedway again.

5.0

4 years ago

Dozer

Ohio

Verified

Don't know how the product works yet. Because I haven't installed it but my friends have used it and said it works great. But I would definitely order from speedway again. They have great prices and they get me my stuff very quickly.

Showing 3 of 3 reviews

Questions & Answers

Fitment

  • GM LM4

  • GM LS2

  • GM LM7

  • GM LQ9

  • GM LM7

  • GM LQ9

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  • GM LQ9

  • GM L76

  • GM LM7

  • GM LM7

  • GM LQ4

  • GM LS1

  • GM LS1

  • GM LS2

  • GM LM7

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ9

  • GM LQ4

  • GM LM7

  • GM LQ4

  • GM LQ9

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LM4

  • GM LM7

  • GM L59

  • GM LM7

  • GM LQ4

  • GM L59

  • GM LM7

  • GM LS2

  • GM LM4

  • GM LM4

  • GM LM4

  • GM LM7

  • GM LQ4

  • GM L33

  • GM LM7

  • GM LQ4

  • GM L33

  • GM LQ4

  • GM LM7

  • GM LQ4

  • GM L33

  • GM LQ4

  • GM LM7

  • GM LQ4

  • GM L33

  • GM LQ4

  • GM L33

  • GM L59

  • GM LM7

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LM7

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LM7

  • GM LM7

  • GM L59

  • GM LM7

  • GM LQ4

  • GM LQ4

  • GM LQ4

  • GM LS1

  • GM LS1

  • GM LS2

Customer Impersonation Script