Based at the University of the West of England, UWE Formula Student is an ambitious, multidisciplinary team uniting students across diverse engineering and non-engineering fields to design, build, and race single-seater competition vehicles. For 2026, the team unveiled UWEFS-13, the thirteenth platform in our history, featuring a hybrid setup that pairs a 675cc Triumph Street Triple three-cylinder engine with two independently controlled in-hub electric motors driving the front wheels. Rather than chasing unnecessary complexity, our primary directive was simple: prioritize platform reliability, finish the build early, and validate performance through intensive track testing.
Supported by the RS Build Fund, this article explores the design journey behind UWEFS-13, focusing on our engineering choices, modular harness architecture, component selection, and how fixing our electrical backbone contributed directly to our top 10 finishes at Silverstone and Spain.
Why the loom?
The loom is the central nervous system of the car, if it fails, the car fails. Last year's harness showed us the cost of treating it as an afterthought: ground loops, signal integrity issues and limited flexibility for servicing hampered our testing on our old car at the start of the year. So, this season the loom became the focus of our RS Build Fund, which supplied the connectors, contacts, splices, heat shrink, braided sleeving and more, behind everything that follows.
This rebuild wasn't just to fix old problems - this car also brought two electrical firsts. Power distribution moved from a mechanical relay box and fuse holder to a solid-state PDM, with Cartek giving us early access to their CAN-enabled 8-channel PDM for beta testing. We also ran an e-throttle for the first time this year, with the twin pedal-position sensors and the throttle body itself all being new to us. Changes of that scale can’t be retrofitted into an old harness; they need a loom designed around them from the start.
An architecture designed to come apart
UWEFS-13's loom is modular - twelve plug-in harnesses rather than one monolith. The split that matters most - another first for us - is at the firewall. The entire engine harness drops out of the car with the engine, disconnecting at a firewall plate carrying four flanged 12-way Deutsch DT/DTM connectors, with main power crossing on bulkhead studs and a star ground point on the engine block. Engine-out jobs no longer involve surgery on the loom, and a potential future powertrain change doesn't mean rewiring the car.
Electrically, the loom connects a Life Racing F88RS ECU and D4 dash, our Cartek PDM (individually programmed and fused per channel), a CAN network with onboard data logging, and a full engine sensor suite, from lambda to brake pressure, with provision to handle suspension potentiometers and rear wheel speed. It also includes our safety shutdown circuit, which feeds an in-house relay control PCB that cuts the fuel pump, injectors and ignition coils.
One source of truth
Every harness was designed, sized and documented in RapidHarness before a single wire was cut. We built stored libraries of our connectors, cables, coverings, terminals and splices, meaning that our drawings use real parts - the front harness alone runs to more than 60 nodes on one drawing. Design started in May; the RS order landed in early June. If it wasn't in RapidHarness, it didn't go on the car.
Wire, connectors and crimps: choosing parts on a student budget
Almost every decision on this loom had to be a cost-versus-specification call, made deliberately.
Signal wiring is TE Connectivity Spec 44: aerospace-grade, lightweight, colour-coordinated for clarity, with a tight bend radius that suits a space-limited chassis. Spec 55 is tougher, but the price difference didn't survive contact with our budget - a compromise we'd have to make again. Power runs use heavier PVC and welding cable from 12 down to 4 AWG.
Connectors are Deutsch DT and DTM series throughout: sealed against the environment, wedge locked against vibration, flexible on wire gauge, robust, reasonably priced - and easy to de-pin, which forgave the mistakes we inevitably made. They're a major upgrade from the SuperSeal 1.5s we ran last year. A detail worth noting: all our connectors were the shrink-boot versions (-E007 on DTM, -E008 on DT), which means they have a small lip that grips heat shrink and boots so the connector-to-loom transition seals properly.
For contacts we chose open-barrel, tin-plated crimps over closed-barrel and gold: the closed-barrel tool costs several times what a ratchet open-barrel crimper does, and tin contacts are cheaper and easier to source. Splices are TE open-barrel brass in three sizes, crimped with the same style of tool and sealed under heat shrink - a technique we picked up from High Performance Academy, whose YouTube and Instagram content shaped a lot of our wiring practice.
Sheathing and finishing: two zones, two strategies
The firewall splits the car into two environments, and the loom's protection follows it. The front half lives in relative cleanliness, so it wears HellermannTyton PET braided sleeving: light, abrasion-resistant and easy to remove when a circuit needs attention. The rear half lives with heat, oil and dirt, so is fully heat-shrunk. Here we made another deliberate trade: HellermannTyton single-wall heat shrink instead of the motorsport conventional DR-25. We gave up a little temperature rating; but the price difference was enormous, and for a low-budget team it was the right call. Joints and breakouts got HellermannTyton adhesive-lined 3:1 dual-wall heat shrink - again chosen over the TE equivalent on price, with no performance complaints.
The same zoning runs down to the tape. At the rear, insulation tape seals patches and cut-ins over existing heat shrink, because fleece tape would soak up oil and grime. At the front, fleece tape wraps the awkward junctions - including one spot between two junctions where braiding physically couldn't be fed in. Retention follows suit: adhesive-backed cable-tie mounts inside the front bodywork hold the runs firm and clear of the driver, while at the rear the loom is zip-tied to the chassis and every solid mount available, so nothing moves near an engine full of moving parts.
Build, break, fix
Manufacture and testing ran from early June to mid-July, with the modular architecture setting the schedule: the engine harness was manufactured, sized and tested first, followed by the front and auxiliary looms - so the highest-risk harness got the most test time.
Not everything went to plan. Mid-build we found mis-pinned wires on the ECU header. With moulded connectors that would have been a rebuild; with de-pinnable DT/DTM contacts it was an evening's careful rework - the moment our connector choice paid for itself. We also ran short of contacts late on, and a last-minute order through RS next-day collection kept us on track for Silverstone. Lesson logged for next year: over-order crimps. They won’t go to waste.
How it held up at Silverstone
UWEFS-13 passed every scrutineering check - chassis, safety, tech, tilt, noise and brake - and finished 10th overall at Formula Student UK 2026, setting a team-record 4.709-second acceleration run along the way. Endurance ended earlier than we wanted with a mechanical issue, but the loom ran faultlessly all week, with no electrical failures across the event. For a harness built in six weeks by students, that's the result we wired for.
The hybrid, and what's next
There's one more thing riding on this loom. UWEFS-13 carries our low-voltage hybrid system, and it works - functionally proven and integrated into the car through this harness and its CAN network. A sheared gearbox tooth, whose root cause we're still chasing, kept it from running at competition. Frustrating, but the hard part is done.
Next year the hybrid work is refinement rather than redesign - mostly deployment logic. Proving the system also unlocks a big potential change on the next car: stepping down from the 675 cc Triumph Street Triple to an engine around 400 cc, with the hybrid system making up the difference. The priority can then be a light, effective, efficient car - and the loom and comms backbone, the RS Build Fund paid for, is the platform it all runs on.
Thank you to RS and the DesignSpark community for the Build Fund. On the surface it bought wire, connectors and heat shrink, but what it really bought was a season of electrical reliability, and the foundations of next year’s car.
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