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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 ★★★★★
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Product Reviews
★★★★★ 5
Good fit, but wire isn’t good for super lg breast
Color: Purple, Size: 36I
While I love the fit of these bras I’ve order almost one in every color, I have to say the wire does break a little easily they always snap right under my under arm now ik I have very large breast I’m between a I and J cup. These are a little tight but you can still adjust them I still love them despite the wire snapping. I’d say they last longer for small breast like my sister I accidentally ordered the wrong cup size and it fit her now she’s hooked on this brand and has an equal amount of colors😂 it’s easy to wash and I wouldn’t say it’s soft because it’s mesh I don’t think mesh is that soft like silk or anything but it’s definitely smooth and see through so my bf and I love that part whenever I wanna get spicy and send a pic during the day.
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Reviewed in the United States on May 29, 2026
★★★★★ 4
Weird smell but cute
Color: Coffee Brown, Size: 36H
Edit: ordered a size up from the size chart cup and it's perfect. Wore it all day at work today and it was super comfortable and nothing fell out.
I did return this same day but it was too small in the cup. I did follow the size chart but I was still spilling out of the top. But the material was very good quality and the color was an excellent match to the listing. I will be ordering the next cup size up to see if I can get it. Only down side was a TERRIBLE chemical smell when I opened the package and took it out. But it was gone in a few minutes.
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Reviewed in the United States on May 5, 2026
★★★★★ 5
The perfect bra!
Size: 46DD, Color: Beige
This is the perfect bra! It’s comfortable, supportive, and the straps do not slide off your shoulders. The material is so soft yet lifts and shapes the sides just like they say it does while also smoothing the under arm and back area. This bra stays put all day and feels like you’re wearing nothing. It’s very well-made with the perfect stretch that covers even under a thin T-shirt. I hate to say how much money and time I’ve wasted on ill fitting overhyped bras but this one is perfection. I will definitely be buying more! My only suggestion is the band size runs a little large so I went down one band size. Cup size is right on.
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Reviewed in the United States on December 21, 2025
★★★★★ 5
So comfortable!!
Size: 38G, Color: White
This is the most comfortable underwire bra I’ve ever worn. I am a 38G cup and it lifts, shapes and supports me all day, minimizes, the back stays in place and is super smoothing. It keeps its shape through a few wears. It has great stretch. It’s so soft. Nice bright white. Perfect for an every day / work bra. And it’s super inexpensive. I’ve bought $80 bras that were horrible in comparison. The only one con it has is that because it’s so soft and stretchy, you can’t wear it more than 3 times without needing to wash it. Otherwise it stops supporting as well because it’s stretched out a bit. But I mean, we should probably be washing our bras more than we do anyway, am I right?! 😆
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Reviewed in the United States on January 9, 2026
★★★★★ 5
THE BEST. Seriously.
Size: 36E, Color: White
The world is upside down. How can a twenty dollar bra outperform my hundred dollar bras??? I don't know but here we are. I am 49, a 34F/36e, 5'1". Finding a great bra is challenging to say the least. This bra is it, y'all. I bought it in a different color a couple of weeks ago. I wore it three times in a row to make sure it wouldn't bag out, lose its support. I washed it, not in a lingerie bag, on warm, dried it on high, to make sure it would hold up to that. It passed both tests with flying colors. It is so comfortable. It feels wireless! It is very flattering, has great under-arm-flub-smoothing and support. The back is substantial and smoothing but without being bulky or restrictive. The straps are wide, but not too wide, and totally stay put all day. I bought the other three colors and the sizing is seamless across colors. This is a winner, folks!!!
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Reviewed in the United States on November 26, 2025