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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:
- 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
4.3 ★★★★★
Based on 24 reviews
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Product Reviews
★★★★★ 3
Our pup loves it (to pieces)!
Color: Fox-Crocodile
Fun toy for our playful pup, but nothing indestructible. She finds a seam and in days, the toy is in bits. Lucky for us, she still enjoys playing with parts! Package of 2. One down, one to go!
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Reviewed in the United States on May 28, 2026
★★★★★ 5
Holds Up Well
Color: Fox-Crocodile
My dog loves this toy and after several months of heavy use he has yet to rip it apart like he's done with every other toy I've bought him. He has a hard time grabbing it with his teeth to play his usual tug of war games.
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Reviewed in the United States on June 8, 2026
★★★★★ 4
Cute
Color: Fox-Crocodile
I love the interactive toys, BUT my dogs are either too destructive or smart because they’ve ripped the little treat part, so I can’t hide stuff in there anymore. Otherwise, they still play tug of war with it. Probably better for smaller or lazy dogs.
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Reviewed in the United States on April 28, 2026
★★★★★ 5
Great Interactive Toy for My Dogs
Color: Fox-Crocodile
I have four dogs with different personalities and energy levels, and these toys have been a fun addition to our home. The two dogs in the photos were the first to test them, and they immediately started sniffing, searching, and working to get the treats hidden inside.
The toys are soft, well-made, and provide great mental stimulation. I like that they keep my dogs entertained while encouraging them to use their noses and problem-solving skills. The treat compartments work best with small training treats, and the toys have held up well during regular play.
Overall, this has been a great enrichment toy for my pack. If you have small or medium-sized dogs that enjoy treat puzzles and interactive toys, I would definitely recommend giving these a try.
The two pups in the photos approved them right away, and the other two quickly joined the fun!
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Reviewed in the United States on June 10, 2026
★★★★★ 5
Great toy for our mouthy chewing very active dog - he loves it and so do we!
Color: Fox-Crocodile
Great buy!
Dog is very mouthy, so got this to try to focus chewing on a toy rather than me, and he loves it.
Pockets are a little small for many treats, but they do hold very small ones tucked into each triangle - (16 small treats total between the two toys), and rolls up with a strong velcro which holds pretty well. Dog will forcefully wedge his nose into the roll trying to get to the treats and it doesn't unroll until he works it over.
Wasn't positive how well it would hold up - he is a very mouthy puppy who is very strong and likes to shred, but out of all the toys, it has held up some of the best (on par with the kong toys so far) where others are not faring so well. He has pulled and tugged at the eyes, feet and ears repeatedly, and they are still firmly attached and no fraying on the treat spots at this time. He throws this thing around playing by himself and aside from being dirty now being one of his favorite toys, it looks as good as new. The only problem we have had is one of the squeakers no longer squeaks as he seems to have managed to remove that part of the noisemaker - but no holes, no rips, no shreds, nothing else showing wear and tear.
He has even used it for tug of war on occasion and though we didn't let that last too long, it showed no signs of tearing or ripping from that either.
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Reviewed in the United States on May 30, 2026