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Description
Holley Terminator X MAX Engine Management Systems 550-918TERMINATOR X MAX MPFI W TRANS CONTROL 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 CONTROL
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 550-918 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:
- Designed for GM LS 4.8/5.3/6.0 LS Truck Engines and LS2/LS3 with 58x Crank, 4x Cam and 4L60E/4L80E transmissions, and EV6 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
- Includes: 58x/4x LS Engine Main Harness - EV6 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.
Specs
| Brand | Holley EFI |
|---|---|
| Crank Reluctor | 58x |
| Emission Code | 3 |
| Ignition Type | GM LS 58x |
| Injector Connector | USCAR (EV6) |
| Product Type | Terminator X Max LS MPFI |
| Terminator LS Options | Fuel, Spark, Transmission |
| Part Number | 550-918 |
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 ★★★★★
Based on 12 reviews
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Product Reviews
★★★★★ 5
Well made , gym quality
Style: 10 Pound, Pair
Color is nice and bright . The weights grips are good they do not slip . Prices reflect quality
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Reviewed in the United States on May 29, 2026
★★★★★ 5
Good purchase
Style: 3 Pound, Pair
These are just the right weight for me to start gaining muscle back in my arms, after a large weight loss. They are of good quality, they are covered in a nice rubber like coating that is soft to the touch. They are small enough that i can take them with me when I travel. My dog has got hold of them a couple times and played with them, and they held up just fine without any damage.
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Reviewed in the United States on April 28, 2026
★★★★★ 5
Solid, grippy, and they don’t roll away!
Style: 10 Pound, Pair
I bought these because I’m finally trying to build a consistent home workout routine and didn't want to drop a fortune on name-brand weights. I’ve been using this 10lb pair for about a month now for everything from overhead presses to lunges, and honestly, they’re exactly what I was looking for.
The Pros:
• That Neoprene Grip: The coating is fantastic. Even when my hands get pretty sweaty halfway through a workout, I don’t feel like I’m going to drop them. It’s a much "softer" feel than cold metal or hard plastic.
• The Hex Shape: This is a small detail that makes a huge difference. Since the ends are hexagonal, they don't roll across the floor when I set them down between sets. They also stay put if I’m using them for "renegade rows" or floor work.
• Compact Size: They aren’t bulky. I can easily shove them under my bed or in the corner of the closet when I’m done.
• No Weird Odor: I was worried they might smell like a tire factory (which happens with some rubber-coated weights), but these had almost no scent right out of the box.
The Cons:
• Handle Diameter: The handles are a little on the thicker side. I have medium-sized hands and it’s fine, but if you have very small hands, they might feel a bit chunky to wrap your fingers all the way around.
• Color Scuffs: The navy blue looks great, but if you clank them together or drop them on concrete, the coating can scuff or show dust pretty easily.
The Verdict:
If you just need a reliable set of weights for HIIT, Pilates, or general strength training, these are a no-brainer. You're basically getting gym-quality equipment for a fraction of the price. I’ll probably be back for the 15lb set in a few months!
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Reviewed in the United States on January 27, 2026
★★★★★ 5
Love my mat!
Color: Pink, Style: 1/2 Inch
I’m new to stretching and recovery classes, and there is a lot of floor work. I was using the gym mats, but my knees, lower back, and glutes were hurting from being on the floor.
This mat is the perfect thickness and feels wonderful during floor exercises. It gives me the extra cushion I need without being difficult to use. It’s also lightweight, durable, easy to clean, and easy to roll up for transport. The pink makes me smile. That said , the mat makes the classes more enjoyable.
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Reviewed in the United States on May 2, 2026
★★★★★ 5
Great value
Color: Aqua, Style: 1-Inch
Perfect exercise mat. It is nice and thick, and comfortable to kneel and lay on. Can't comment on durability, but so far, so good. Recommended.
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Reviewed in the United States on May 14, 2026