so when i'm talking about a turbo'd engine I have to say it's 2.5L but it behaves like a 4L or 5L?

Or how about the meguiar's focus, it's a 2.0L (may be bored a bit larger) but it behaves like a 20L??

get real. it's a 1.3L. yes it's a wankel and makes power differently, still it's a 1.3L.