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Description
Holley Terminator X MAX Engine Management Systems 550-916TERMINATOR X MAX MPFI W TRANS, LS1 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
TERMINATOR X MAX MPFI W/TRANS, LS1
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 550-916 also has 4L60E or 4L80E Transmission 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 with EV1 injectors and 4L60E/4L80E transmissions
- 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 1-bar 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
- Includes: 24x LS Engine Main Harness - EV1 Injector 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 vacuum adapters.
Application
- 1998 - 2002 Chevrolet Camaro
- 1997 - 2004 Chevrolet Corvette
- 1998 - 2002 Pontiac Firebird
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, Transmission |
| Part Number | 550-916 |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- 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
4.2 ★★★★★
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Product Reviews
★★★★★ 5
Classic and functional
Color: Stainless Mesh/ Blue Dial
High quality and affordable watch. Love the mesh band. It’s a classic, functional everyday look. Easy to adjust, and never runs out of power. Perfect for men who have smaller wrists. Bought for my husbands birthday, and he loves it.
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Reviewed in the United States on July 31, 2025
★★★★★ 5
Everything as expected
Color: Stainless Mesh/ Blue Dial
It's a nice watch added to the collection, looks really good on hand, the metallic mesh band is very elegant and also customizable, so it will fit perfectly on your hand.
It seems that it had a bit of charge out of the box, but I'll leave it under a direct (under 20cm distance) LED desk lamp to recharge overnight, I'll also leave them under sunlight around the windows whenever possible (at least for the first week or so), it's stated in the online manual that it will need ~45 hours to fully charge on a cloudy day under the sunlight.
By the way, it would've been nice to have the manual in the box, but at least it's easy to find the (generic) manual in their website.
The fluorescence of the hands and hour dots are really bright and mine had nice bluish color.
Of the features, the chronograph works perfectly as expected, the manual also states to set the time 5 minutes ahead of the real time then slowly rewind back to the current time whenever setting the time, for the time keeping to be more accurate because of some gear movements inside.
To be honest, it would be great to see Citizen use scratch resistant sapphire instead of some mineral as the face protective layer, as they do for other high-end models, the technology is not new and I think it wouldn't make it that much more expensive, I hope this one will be resistant enough🤞🏻
Overall, this is the first day I received the watch, I'm quite happy with my purchase, it's nice knowing you won't need to replace the battery anytime soon 😛
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Reviewed in the United States on December 12, 2023
★★★★★ 5
Great World Time Watch!
Color: Stainless/ Black Dial
The usual quality Citizen construction, Eco-Drive, and a very handy world time bezel. FIVE STARS!
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Reviewed in the United States on February 8, 2026
★★★★★ 4
Great watch for the money
Color: Stainless Mesh/ Blue Dial
Looks great. I swapped out the band for a leather strap. Nice watch, well designed. My other eco drive has been going strong for 15 years or so without a hitch. So I have high expectations for this one.
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Reviewed in the United States on January 9, 2024
★★★★★ 5
Great Gift
Color: Stainless Mesh/ Blue Dial
It was a gift for my Dad but he loved it! Very worth it
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Reviewed in the United States on April 23, 2026