In recent years there has been much talk of the "magic" Q3 qualifying mode that Mercedes (and now Ferrari) have. In particular Mercedes always seem to bring something extra when entering Q3. I find the existence of such a mode puzzling in the current engine formula. In the past, the notion of "turning up" the engine for qualifying was very natural. The maximal power output was limited by how much fuel you could burn in the engine. The effective limit was the result of mechanical limitations of the engine, and was certainly possible to exceed the limitations for a short time (by increasing the max revs or boost pressure) at the cost of reducing the mechanical life of the engine. However, the current engine formula is fundamentally different. The maximal power output of the engine is (due to fuel flow limit) limited by how efficiently the engine burns its constant supply of fuel. A temporary increase of power therefore has to come from a temporary increase of the thermal efficiency of the engine. I have a hard time imagining ways in which one could do this that could not be sustained for longer periods of time, or would limit the life of the engine. Of course, the alternative is that the engine is drawing from some other limited supply of potential. Clearly, this is where the speculations of engines burning lubricant oil for a power boost come from. I guess the engines could also be consuming itself (either for fuel or some substance acting as a catalyst leading to a more efficient burn). Any ideas on the physics behind the special Q3 modes?