ELI5, Why do some engines, even though they are the same size sound different. For example, a BMW s1000rr has the almost the same engine as a Kawasaki zx10r, but, they sound so different at idle.

Question

ELI5, Why do some engines, even though they are the same size sound different. For example, a BMW s1000rr has the almost the same engine as a Kawasaki zx10r, but, they sound so different at idle.

In: Engineering

Answer 1

Engine sounds come from a multitude of factors. The sound you actually hear is the valves opening and closing.

You can take 2 identical engines and change the valve timing, and get different sounds.

So while the 2 engines might be similar in spec, the way the Rev, speed they Rev at etc, will dictate what valve timing is needed, and thus change the sound of the engine