Generation Nexus

Haltech’s new nexus r5 attempts to rewrite the rulebook on engine management and vehicle control electronics. Here’s what it could mean for your street machine

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Most of us are familiar with the concept of fuel injection systems and the Engine Control Units (ECUs) that run them. But Haltech’s new NEXUS R5 really stands out from other ECUs, as it is designed to manage so much more than just the engine. That’s why Haltech is calling it a VCU – Vehicle Control Unit.

The box plays host to not only an ECU but also another three-letter acronym: a PDM, or Power Distribution Module. What’s that, you ask? Well, first let’s talk about wiring.

The most conventional way to wire up a car is to use a fuse-and-relay system, where the wiring loom connects any high-current-draw devices (thermo fans, electric pumps and the like) to the battery, first through a relay and then through a fuse. This is usually the cheapest way to get your engine running, but it can also be the most complex, as the ECU needs to send a low-current signal via the wiring harness to a relay, which can be thought of as an electronically controlled switch. The relay then provides the high-current power supply to the device via another set of wires. So with just a few basic devices, plus injectors, ignition and the ECU itself all connected to battery power (and then also connected to the input switch that’s used to turn the devices on or off), you can very easily end up with a large and daunting wiring loom. When all of these wires are also fused for short-circuit protection, you have even more connections and complexity thrown into the mix.