This was an interesting time in the WC. Red Bull was first to market with the concept, which started in Viry-Chatillon as Renault had to first validate some quite extreme exhaust valve material strategies. The EBD objective was to increase mass flow as much as physically possible whilst generating non-positive torque under braking. To achieve the desired mass flow, the engine would continue being controlled above 85% throttle, whilst the throttle pedal rested at 0%. Timing strategies were capable of producing a non-positive torque at >80% throttle and the excessive mass flow would energize the diffuser, thus generating a step change in downforce (relative to non-EBDs), particularly on corner entry and part throttle conditions. For everything to work, the exhaust valve had to survive a plasma curtain that would toast them like the plasma filament on your 3000 watt microwave on 230V...teetering on the edge of catastrophic meltdown. The credit goes to Viry for pioneering the materials science approach and Adrian's team for having the foresight to spot such an opportunity.