Why are lawn mower engines so loud, while my car is quiet?

Question

I just came back from a drive and I’m wondering why my 3.0L I6 engine which has roughly 385HP is relatively quiet besides a low growl compared to my extremely loud lawnmower which as a tiny 6HP single cylinder? Would the muffler of my car make that much of a difference?

In: Engineering

Answer 1

Also compare apples with apples. Lawnmowers operate at their highest power setting almost constantly when being used. Cars mostly cruise at about 30% power or less. Rev your car’s engine to 80% of its redline and hold it there. See how noisy it gets to an outside observer? When I throttle back on my lawnmower to empty the grass catcher, it is quite muted.