MY AUDI S5 HAS LOST HUGE POWER!

The video follows a hands-on workshop session at Darkside Developments in Barnsley UK where the host takes an Audi S5 with a 4.2 V8 to the dyno for the first time to quantify a mysterious power loss. The opening segment establishes the problem as a known carbon buildup issue on direct-injection engines, and the crew plans a walnut blast to remove carbon before re-dyno testing to verify gains. After the walnut blasting, the engine is reassembled with careful attention to the intake and injector area, noting a few oddities such as a non-original injector setup and questions around why certain components were altered. The second major phase documents the re-run on the dyno, which shows a modest horsepower increase yet still leaves the car well under its stock spec, with around 236 bhp originally and a final post-clean result in the 239 bhp range on one test, then a lower figure on the subsequent run. The video closes with reflections on the remaining performance gap, discussion of possible causes such as injector issues or fuel pump behavior, and a tease for an upcoming exhaust upgrade to push the power higher, while also praising the workshop and inviting viewers to follow the Darkside Developments team for updates. Throughout, the host is transparent about the numbers, explaining that carbon buildup on direct-injection engines can steadily erode performance, and that the walnut blast is a targeted treatment to restore flow and efficiency. Visuals include the intake manifold removal, carbon buildup visible on the valves, and the walnut blasting process itself, interspersed with dyno footage and in-workshop closeups. There is a practical emphasis on not overhauling injectors during the same trip due to logistical constraints, balanced by a commitment to monitor the impact of the cleaning on power delivery. The extended plan for further investigation and an exhaust system upgrade signals a continuing project narrative rather than a one-off repair, keeping viewers engaged with the progression and outcomes as new content in the series.

Topics · Autos & Vehicles · Automotive performance · DIY & Car Maintenance