Post here all non technical related topics about Formula One. This includes race results, discussions, testing analysis etc. TV coverage and other personal questions should be in Off topic chat.
Just as a reference here's a youtube video. But the question I wanted to know (which I wondered since the new engines) is what is the weird burbling popping sound these engines make under deceleration. You can hear it far more pronounced on the honda yet it's barely a brrr noise on the Merc and somewhere in between for the rest. https://www.youtube.com/watch?v=f3rY0HCBUck
I don't have a lot of experience and it might turn out that I'm talking non-sense but here's what I think it is:
When the cars are decelerating and engine speed needs to come down too to match vehicle speed (this, of course, is all before the downshift occurs). In order to let the engine decelerate, either fuel is reduced drastically (running very lean) or shut off completely, and/or the engine is running at a very retarded/delayed spark compared to normal; i.e. spark occurs when the piston is much closer to its TDC position (TDC is when the piston is closest to the cylinder head) than under normal operation. Such extremely lean or delayed spark timing can lead to very slow combustion or even a misfire. So all the unburnt fuel is being burnt in the exhaust pipes and this causes that burbly/bursty/popping sound. The reason why Merc sounds much smoother can come down to how they handle this transition from normal operation to engine deceleration mode. Probably Honda runs lean/delayed spark under engine decel and Merc completely cuts off fuel and hence you don't hear the misfires. Other than that, I don't have a great answer to how/why they are so different.
