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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
4.2 ★★★★★
Based on 21 reviews
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Product Reviews
★★★★★ 4
My dog loves it...but needs charging four, five times a day. You really need 2 for full-time play
Color: Blue
My dog loves this toy.
The first time she saw it and it started rolling, bounding, and waving the ropes around...she was barking at it, chasing it, grabbing it, jumping all over the place.
There is no other toy she has that she will leave this for.
And...that's part of the problem.
I have to take this away from her three, four, five times a day to recharge it. The charge barely lasts an hour and the toy is dead. And it takes over an hour to charge it all the way up. Which means she plays with it less than it spends charging. That's not ideal.
The product page and manual that comes with the toy says there is a 10-minute play period followed by a 30-minute interval to let the dog cool down...not get overly stimulated.
I have never seen a cool-down period. I don't know if it's because the dog plays with it, shakes it around, tosses it and chases it, etc., etc., etc. constantly...but it just keep going until the battery is dead.
I wish it did have a cool-down period. She likes playing with the ropes and rolling it around herself even after the battery dies, so if there was a cool-down, maybe it wouldn't need to be charged many times a day.
Once it's charged and she sees me putting it back together, she gets very excited and starts jumping up and trying to grab it.
Our corgi reduces most rope toys to threads in a day or less, and this one has held up surprisingly well against her super-chewing habits. The material the ball part is made of is very durable (we have a couple other toys with the same type of shell) and she's chewed on them all a lot without any damage.
The toy keeps her entertained and happy...when it's not on the charger.
I wish it was a good-enough value for the money to be able to justify buying two of them so I could have one charging while she was playing with the other.
=================
I'm adding 1 star, because the company customer service is outstanding. They emailed me about my concerns vis-a-vis the short battery life, and it seemed that they really listened and cared about my input.
I don't know what, if anything, can be done to extend the battery life given that it's spinning some substantial pieces of rope around, but I think they'll do as much as they can.
In the meantime, my dog's love for this toy has not diminished in the least. She still gets very excited when she sees me starting to put it together after it's done charging, and she ignores everything else (sometimes even offers of treats) to play with it.
I have a second one now, and I can almost keep them going full-time, but the few minutes every couple hours when both of them are on the charger is probably good for her anyway...she'd probably be over-stimulated if she had one of these to chase non-stop.
Summary: Great toy, lots of fun, my dog loves it. However, you really need two the way things are right now unless you are okay with your dog being able to play less than half the time.
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Reviewed in the United States on March 13, 2026
★★★★★ 5
My German Shepherd loves it!
Color: Blue
My GSD loves this thing! It bounces and the rope thing wiggles and spins. She is supervised while playing with it. The charge lasts about an hour or so. The only thing that is a little annoying is it makes a little barking sound on one of the settings. It screws apart for easy access. So far she's not been able to destroy it but she has opened it so definitely supervise playing time. It rolls around and bounces on the carpet and on the hard floor it jumps a little bit. Can be loud on hard floors. It's a soft rubber kinda texture that is easy to rinse off and clean. Probably best for indoor use or use on decks or patios. Keeps her very engaged and I have a blast watching her and playing with her with this thing!
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Reviewed in the United States on March 18, 2026
★★★★★ 3
Not for chewers
Color: Blue, Color: Blue
Ok, first off, my dog absolutely loved this toy. Still loves it. However: it only took him two days to utterly destroy the part that made it interactive. The rope fastened to the small interior plastic part that is moved by the rechargeable motor was too soft for him and he chewed it off right at the root, where it attached. This makes the toy immobile. It still makes noise and vibrates, but it no longer leaps and bounces. So now he carries it around while it vibrates inside his jaws and I watch his ears jiggle and make sure he doesn’t eat the whole thing. Please note: this is a medium sized Corgi, not a huge dog like a Rottweiler. There is no way to add a new rope to that interior plastic piece: they are made as an inseparable unit. You have to buy the full replacement set which includes a new cover.
I would recommend this toy for someone whose dog is NOT a chewer. For someone whose dog loves to chase, and is excited by noise. If those pesky squirrels chattering outside really get to him, this toy will be his new favorite. But if your dog likes to chew and has more than two teeth in his mouth, this toy is not a great choice and you should spend your money on something that will last a bit longer. It’s not a good value for the money. I bought this original toy and a replacement cover+rope set, and I’m not going to give him the replacement cover for a long, long time. I can’t afford to replace these every few days! Thankfully he still loves the toy despite the fact that it doesn’t run away from him, and hasn’t tried to eat the foam covering, so it’s just the softness of the rope I am disappointed in. But I’m not going to buy this again and can’t recommend it highly, based on my experience, despite my dog loving it and the joy I get watching his ears shake as he trots around the house holding onto this expensive mouth vibrator.
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Reviewed in the United States on May 14, 2026
★★★★★ 5
Excellent product
Color: Orange
Excellent product gave as gift and was enjoyed by the labrador.
The tail makes all the difference.
Would recommend.
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Reviewed in the United States on May 20, 2026
★★★★★ 2
Not worth it - (2nd day of having product)
Color: Orange
Fun toy out of the box - Frenchie dog.
Charge does not last long. Even with recharging, the motor seems weaker. It asks to keep the charging port dry, but it is not slobber-proof, so when opened, the entire inside is wet - I have to blow-dry the charging port in order to be able to recharge it
Day 2 - movement is so weak, but it shows full charge. Barking sound is no longer audible. If you have a chewer... not great as it is easily broken apart. Not really worth it. At least it's cheaper on Amazon than their website.
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Reviewed in the United States on January 16, 2026