Engine Management Accessories

The parts around an engine management system decide how safe, tidy and serviceable it is. This section holds power distribution modules, fuse and relay boxes, relays, multicore cable, sleeving and firewall grommets. Crimping tools, mounting kits, USB cables, Wi-Fi antennas and a few track and dyno items round it off.

A power distribution module (PDM) replaces fuses and relays with programmable electronic outputs. Each output measures its own current, so a fault can be switched off, retried and logged instead of blowing a fuse. Outputs can also follow conditions sent over CAN, such as running a fan by coolant temperature.

Where a conventional layout suits the car better, a sealed fuse and relay box keeps those parts dry and together. Relays then let a light switch control a heavy load without carrying its current.

Pick by function:

• Power distribution: a PDM alone, with a plug and pin set, or with a 5 m flying-lead harness.
• Fuses and relays: a waterproof 28-way mini fuse and relay box with a grid layout, and a 6-circuit fuse box with its pins. Relays include a 30 A power relay, a 12 V 35 A normally open micro relay and a 100 A solid-state relay.
• Cable and protection: 10 m reels of colour-coded 4 × 20 AWG and 3 × 22 AWG multicore, and a harness sleeve pack. Firewall grommets of 51 mm outside diameter have 21 or 28 mm bores, and the 63.5 mm size a 44.45 mm bore.
• Tools: crimping tools for DTM, DT and DTP solid contacts, and a 5-ton hydraulic crimper for large cable lugs.
• Mounting and connection: tube mount kits for 1.25 in and 1.625 in tube, rail-type ECU mounts, waterproof and USB-A to USB-C cables, USB caps, and 2.4 GHz Wi-Fi antennas.
• Track and dyno items: a dual-channel kit for listening to knock while tuning, and a 450 mm (18 in) parachute safety flag.

Size every fuse or PDM output for the cable it feeds, and keep the main supply short and well protected. A solid-state relay suits loads that switch often, as it has no contacts to wear, but it gives off heat and needs a mount that carries it away.

Pass each loom through bulkheads in a grommet sized for it, and sleeve it wherever it meets heat or abrasion. Tube mounts let a module sit on the roll cage, clear of the floor where water collects. Cap unused USB ports, and route antenna cables where they cannot be pinched.