Britcar 2026: Box3 & Datum Step Into GT Class With a Fully Evolved G55

Box3 and Nick are heading into their second season together. Last year, alongside Datum Engineers, the G55 Supercup ran in Britcar’s Ginetta class — one of five categories, positioned mid-pack in the overall structure.

2026 changes everything.

Britcar now runs just three classes, and Box3 moves into the GT class. That shift alone alters the competitive landscape before a wheel turns.


Britcar 2026: Fewer Classes, Tighter Focus

The Britcar 2026 classes now consist of:

The Challenge class sits at the top, balancing cars like Huracan Super Trofeos and Porsche 992 Cups using pit stop timing differences.

GT class — where Box3 now competes — balances GT4 machinery and G55 Supercup cars using technical BoP and pitstop strategy.

Power-to-weight rules now shape competition more clearly. In GT class, cars cannot exceed 350bhp per tonne based on declared weight and flywheel output.

This isn’t simply a class move.

It’s a recalibration of where the car sits in the hierarchy.

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Winter Evolution: More Than a Refresh

Over winter, Tom led a detailed engineering programme. The Ginetta G55 GT4 upgrade touched nearly every system.

The ECU — now our own rather than the previous stock unit — allows adjustments to throttle response and calibration refinement. Engine mapping is significantly smoother on gearshifts and partial throttle. That may not sound dramatic, but smooth torque delivery reduces driveline shock and improves traction consistency — especially when GT4 ABS and traction control are active.

The car now runs ABS and traction control, each with multi-position adjustment. Combined with a high compression engine and refined calibration, the power delivery is more precise rather than simply more aggressive.

Side exit exhausts have been added. They sound epic. More importantly, they alter packaging and heat management around the rear.

Race-Keeper integration ensures that all of this data is captured and analysed properly. In a GT class environment, feedback isn’t optional.


Driveline, Chassis and Durability

Under the surface, the hardware has evolved significantly.

The drivetrain has been re-engineered to cope with the additional torsional load introduced by traction control and sustained endurance running. Rather than focusing on individual component specifications, the objective was strength, stability and durability under repeated torque cycling.

With traction control actively modulating power delivery, reinforcing the load path from differential to rear hubs becomes critical. Reduced compliance improves throttle clarity and long-run consistency.

A G56 front bumper improves airflow and front-end efficiency. Brake cooling has been improved to manage the additional thermal load introduced by ABS cycling.

Alongside this came the essential refresh work: gearbox rebuild, new clutch, and full reliability preparation.

This is the difference between upgrading and rebuilding properly.

What Changes for Nick

Nick has only driven the G55 Supercup. This year, he manages systems.

ABS and traction control introduce new layers of decision-making. Throttle mapping is adjustable. Torque delivery is smoother. Aero balance is more sensitive.

The sprint versus endurance mindset becomes real here. Instead of attacking every lap, he’ll manage tyres, brake temperatures and intervention levels across stints.

The high-friction reality is simple: more adjustability increases the margin for error. The window is narrower in GT class. Competitors are more evenly matched.

In my experience, the biggest gain won’t come from peak power.

It will come from how precisely Nick uses the tools now available to him.

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The Bigger Picture

Last season established partnership. This season raises expectation.

GemClean continues its support as a key sponsor, backing the programme as it steps into a more competitive GT category. Race-Keeper’s data capability becomes central to extracting pace in a balanced class environment.

Britcar 2026 is all change. Box3 and Datum haven’t reacted lightly. They’ve re-engineered the car to compete properly in GT class.

Conclusion

The move into GT class isn’t symbolic.

It’s structural.

Britcar’s class reduction increases competitive density. The car now runs a custom ECU calibration, smoother engine mapping, a re-engineered drivetrain, improved brake cooling, ABS, traction control and refined aero development.