Summer extreme flooding in Central Europe is often associated with Vb-cyclones which travel through the Mediterranean, then northwards east of the Alps towards Central Europe. Extreme convective precipitation intensities scale with the Clausius-Clapeyron relation under global warming. This study quantifies the importance of convective precipitation during Vb-events in present and in warmer climate by simulating selected Vb-events with convection-permitting grid-spacing. A simple convective precipitation diagnostic is compared against Lagrangian convective cell tracking. The simple method shows skill identifying convective precipitation in coarser simulations with parameterized convection. On average, 30\% of precipitation is classified as convective in reanalysis and historical EC-Earth3 driven simulations. This fraction increases to 52\% in a warmer climate under SSP5-8.5 scenario. The increase is explained by a frequency increase of the convectively active cut-off low-pressure systems and a doubling of the convective fraction in the less active trough-like Vb-cyclones, suggesting amplified flood risk in a warmer climate.