Terminator-X: Holley’s New Affordable LS Engine EFI Controller

Terminator-X sounds like a sequel to an Arnold Schwarzenegger movie — but this is something Holley has built even smarter and more powerful than a Skynet T-1000. However, unlike the shape-shifting android from the movie, the Holley Terminator-X is all about control — and in this case its command over the ever-popular LS engine.

Condensed down to its basics, Holley created a very affordable way to finish off a late-model LS engine swap with fully functioning EFI. In the past, your choices were fumbling with the factory wiring harness and ECU, or using the stock ECU combined with a more functional aftermarket ECU, or spending over $2,000 for a complete retrofit laptop-tunable aftermarket ECU system. Now with the Terminator-X, you can have the advantages and ease of aftermarket tuning with an affordable ECU and harness package.

Holley’s Terminator-X and Terminator-X MAX systems offer control over a breadth of GM or aftermarket high-impedance injectors, with provisions for either a cable- or electronic-actuated throttle body. The MAX version will control drive-by-wire (DBW) engines with an option to also control an electronic-overdrive automatic like the 4L60E or 4L80E. There are a ton of details to run through for this system, so let’s get to it.

The view of the Terminator-X ECU and its hand-held device may not be visually impressive, but its combination of functionality at an affordable price is what makes this ECU package attractive. When you take the Terminator-X out of the box, this is what you’ll see. The main ECU is accompanied by a 3.5-inch touch-screen handheld unit, a Bosch LSU 4.9 wideband oxygen sensor, and a complete wiring harness and injector harness. The injector harness is separate so different injectors can be easily accommodated without changing out the entire main harness

Digging Into The Circuits

The Terminator-X uses the same basic software as Holley’s upscale HP and Dominator systems and employs its successful self-learning capability. Holley says this is a plug-‘n-play system. So, once you’ve selected the proper part number for your engine, all you have to do is plug into all the sensors, connect a couple of wires for power and ground, input your engine data, injector size, and some simple air-fuel ratio commands, and the ECU does the rest. No laptop is required — but if you have one, you can access certain tuning charts which are not available on the 3.5-inch hand-held touch screen.

Simplicity is the Terminator-X’s intended function point and is aimed at engine swappers. As an example, let’s assume you’ve just dug up a nice iron-block, 6.0-liter LS engine, originally from a 2001 truck, and you’d like to drop this into a sweet little ’67 C-10 pickup. This engine uses a cable-driven throttle body with a 24x crank trigger and a 1x cam sensor at the back of the block.

The small blue vacuum hose is the connection for the built-in, one-bar MAP sensor. But, if your plans include playing with boost, you can easily configure an external MAP sensor that fits your needs and the harness has a built-in connector already in place. On the right is the Terminator-X MAX ECU, which features two additional harness connections. One connector is for electronic throttle, while the other is for transmission control. Other than these control options, the MAX offers no additional features or tuning controls over the standard Terminator-X, so there’s no reason to purchase the MAX unless you intend to use drive-by-wire throttle or transmission control.

We’ve listed the various Terminator-X systems in our parts list below, but this engine would require the P/N: 550-904 system, assuming the use of the factory Multec injectors. Of course, if later you decide to swap injectors, different harnesses are available that will plug right in, so you aren’t confined to a single-choice throughout the life of the single system.

Besides the fact that it plugs right into your LS engine, some of the advantages to the Terminator-X include control over things like two electric fans, along with other control mechanisms such as a rev limiter, nitrous tables, turbo boost, and an integrated datalogger that can be employed for all kinds of tuning and diagnostics.

DESCRIPTION P/N:
Terminator-X, LS1 24x/1x, EV1 injectors 550-903
Terminator-X, 24x/1x, truck Multec injectors 550-904
Terminator-X, 58x/4x, late-truck EV6 injectors 550-905
Terminator-X MAX, 24x/1x, Trans control 550-916
Terminator-X MAX, ’97-’07 LS, Trans control 550-917
Terminator-X MAX, ’07-up 4.8 / 5.3 / 6.0 truck 550-918
Terminator-X, MAX, 24x/1x DBW 550-929

 

This view of the side of the Terminator-X ECU reveals 8 indicator lights used for instant diagnostics. There are two lights currently unused, with the remaining six covering ECU power, engine run, wideband status, TPS calibration, crank signal, and cam signal.

Dealing With The Pressure

Both the Terminator-X and MAX employ a built-in one-bar MAP sensor, which makes integrating the system much easier. In the past, we’ve had issues with coordinating the correct aftermarket MAP sensor with the Holley HP which caused a bit of grief. The built-in sensor of the Terminator-X eliminates this potential issue.

However, if a supercharger or turbocharger is in your wheelhouse, the Terminator-X’s included wiring harness is exactly the same as the HP and Dominator systems. This means an external two-bar or higher MAP sensor can be used to read boost. However, it will need to be calibrated in the system. Another cool feature of the Terminator-X is the boost control can be managed with the handheld, so this advanced feature doesn’t require the use of a laptop for the basic integration and tuning.

The same is true with nitrous tuning. You can set up progressive nitrous pulse-width control, nitrous-specific Air/Fuel ratios (AFR), trigger points, timing retards and other options all with the handheld unit. Speaking of AFR, the Terminator-X and MAX both employ the latest in Bosch wideband oxygen sensor technology, utilizing the LSU 4.9 version sensor. The 4.9 sensor does require a different connector than the earlier 4.1 version. Since the harness was originally designed for the 4.1 sensor, there is an adapter included which makes this conversion literally a snap.

The 3.5-inch touch screen is all you need to input data and make multiple tuning updates. While a laptop offers access to more sophisticated tuning parameters, you can do everything needed with this simple handheld device. If you like to get into the minute details, the Terminator-X software is fully accessible from a laptop, with much of the same tuning freedom offered by the more upscale HP and Dominator systems. This is a screen shot of a volumetric efficiency table used to create the fuel curve.

Other features included with the Terminator-X and MAX also include the ability to create an offset base fuel map. This allows you to create a custom fuel curve for different fuels such as E85, in addition to various concentrations of ethanol blends, like E30 or E50, using a factory GM flex-fuel sensor in the fuel line.

All of the popular options for tuning can be handled with the 3.5-inch touch screen. But if you want to get more sophisticated — or are just more comfortable with a keyboard — a laptop can be easily configured to dive into both the basics as well as the more in-depth aspects of the Terminator software.

We will follow this story with an installation test on a budget-oriented truck engine we’re building. But from the start, it appears the Terminator-X, and its cousin MAX, are destined to become a popular choice for engine swappers and LS aficionados. The whole idea behind having fun with cars is not having to struggle with complex EFI systems. It appears the Terminator-X has a direct line on removing headaches, and making LS engine transplants simple, easy, and fun.

Here’s a package we find alluring on the left. Start with an affordable 6.0L, add a set of ported, factory 5.3L heads to bump the compression, and a mild cam. Then bolt on an inexpensive Trailblazer SS OE truck intake and control everything with the Terminator-X ECU. (Right) One option for the Terminator-X MAX box combines engine management with the potential to also control a 4L60E or 4L80E transmission. The Terminator-X MAX could control both the engine and trans and save the expense of a separate transmission controller.

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About the author

Jeff Smith

Jeff Smith, a 35-year veteran of automotive journalism, comes to Power Automedia after serving as the senior technical editor at Car Craft magazine. An Iowa native, Smith served a variety of roles at Car Craft before moving to the senior editor role at Hot Rod and Chevy High Performance, and ultimately returning to Car Craft. An accomplished engine builder and technical expert, he will focus on the tech-heavy content that is the foundation of EngineLabs.
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