Multi cylinder car engines (V16 and more)

[230TE]

In a moment of idle curiosity I found myself wondering whether any car had ever used an engine with more than 16 cylinders. I can think of a few V16s (Cadillac, Cizeta, BRM - a more diverse bunch of V16 builders would be hard to imagine) and an H16 (BRM again) but I can't find anything with more cylinders than that. Any suggestions?

[kambites]

I think Bugatti had a W18 (three banks of six) engine in some of their concept cars. It never made production, though.

[Zod]

Aren't the W engnes four banks, i.e. two V engines shoved together?

[kambites]

Zod said:

Aren't the W engnes four banks, i.e. two V engines shoved together?

The term is used to refer to both configurations.

I have vague memories that someone even built a W3 at one point.

[Snoggledog]

As soon as you start going above 16 cylinders you tend to be in the marine or airplane engine realm.