Overview
The 903 enters the 2026 CALM All Porsche Trophy season as the most comprehensively developed version of itself yet. Following an intensive winter programme, the car carries a series of targeted upgrades designed to translate its 425bhp potential into consistent, reliable performance across a full season of racing.
The powertrain package is complete: the Rotrex C38-81 supercharger running a 70mm pulley, the bespoke Alpha Performance Fabrication intercooler, and the Snow Performance water/methanol injection system together deliver 0.95 bar of intercooled boost within safe tolerances. To keep the drivetrain properly balanced at this power level, a dedicated gearbox oil cooling system has been added, routing oil through a Mocal pump and 16-row cooler mounted behind the right-side rear wing intake. The gearbox can now sustain race loads without thermal compromise.
The braking system has been brought up to the same standard. A Balance Beam Brake Pedal Assembly, as originally fitted to the 911 SC RS by Porsche, replaces the previous single-master-cylinder setup. Two brake master cylinders in parallel allow precise mechanical distribution of braking force front to rear, complemented by a Wildwood remote brake bias adjuster operable from the cockpit while driving. For the first time, braking capability is fully matched to the power available.
One unfinished piece of business heading into the season was the engine mapping. With so many changes to the powertrain over the winter, a full remap by Dave Rowe at EPS was essential before the car could be run safely at increased boost. Scheduling meant this critical work could not be completed before the opening round, and the decision was made to miss Croft entirely rather than race before the car was properly mapped.
Round 1: Croft Circuit, 11th & 12th April 2026
With the revised powertrain package in place, a new engine map was required before the car could be run at increased boost. The mapping could not be completed in time for Croft, so the round was sat out. A frustrating start, but the right call.
Round 2: Donington Park GP Circuit, 30th May 2026
The second round of the season takes place at Donington Park on the full GP circuit, with the 903 entered in the CALM All Porsche Trophy for two 20-minute sprint races. With the engine mapping completed by Dave Rowe at EPS on 20th May, just ten days before the race, it represents the first true opportunity to race the 903 at its full 2026 specification.