SKU: 26895536892

Holley Terminator X MAX Engine Management Systems 550-929

Sale price$899.98 Regular price$999.98
Save 10%

Pay in installments of $250.00 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Aug 1 - Aug 6

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

Holley Terminator X MAX Engine Management Systems 550-929Take 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

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 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 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
  • 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
  • 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.

Specs

Brand Holley EFI
Crank Reluctor 24x
Emission Code 3
Ignition Type GM LS 24x
Injector Connector Jetronic / Minitimer (Bosch)
Product Type Terminator X Max LS MPFI
Terminator LS Options Fuel, Spark, Drive-by-Wire
Part Number 550-929
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 26895536892

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.8 ★★★★★
Based on 18 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
P
Verified Purchase
Pamela Baloga
West Palm Beach, US
★★★★★ 5
Storage in the office
Color: Black
This is such a perfect storage for the office with no drawers. Works very well
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 5, 2026
T
Verified Purchase
T. Tozawa
Carnegie, US
★★★★★ 4
Premium quality
Color: Black Linen Texture
This is a premium looking and feeling drawer organizer. No assembly required and the drawer action is very smooth. The quality of the material is nice and thick and doesn’t feel cheap at all. Very sturdy and you can place pretty heavy objects on top without worry; maybe 20lbs or so. Great size for all your little gadgets or accessories and the clean modern looks sleek on your desktop. Just the price feels a bit expensive.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 28, 2024
E
Verified Purchase
Edward O Bogosian
Alexandria, US
★★★★★ 5
It is well worth the few extra bucks compared to other competing products.
Color: Black
Its very elegant looking,sturdy and efficient,uncluttering a messy desk top, quite nicely.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 13, 2026
J
Verified Purchase
JoahJ
Boise, US
★★★★★ 5
It's exceptionally NICE!! BUY this one.
Color: Square Tissue Box-retro
Sturdy, solid construction. The magnetic closure works great. The interior of the holder is expertly crafted and finished. The exterior is Beautiful! It looks absolutely elegant. I am impressed! This facial tissue box cover exceeds my expectations and it is an exceptional value. Do not hesitate to purchase this marvelous cover.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 25, 2026
G
Verified Purchase
GSB
Belleville, US
★★★★★ 5
Sturdy and good fit.
Color: Multifunctional Tissue Box-retro
Well made and perfect for the drop down table in between our two recliners in our couch. Holds all four of our remotes. Tissues come out easily and are easy to put into the holder as well. Looks very fancy. Great value for the money.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on July 15, 2025

recommand products