# Is there such thing as horsepower per cylinder?

I've heard of power per liter but is there such a thing as power per cylinder? I mean, I know more cylinders would mean more power for an engine.

For example, a 6.0 L naturally aspirated V12 can make 700 horsepower. If it was a V10 and all factors were equal, would it make 583.33 hp?

• Welcome to Motor Vehicle Maintenance & Repair! There's really no way to answer this question. If everything else is equal, then most likely. There are so many variables, there's no real way to tell. Commented Sep 6, 2021 at 1:01
• Yes, there is a Morse test. Commented Sep 6, 2021 at 4:12
• And it will always be horsepower per cylinder for a single cylinder engine. Commented Sep 6, 2021 at 4:40

One can always define such thing, but I have not seen it in theory books and I doubt it could have a good practical use.

There are types of internal combustion engines (e.g. marine-use very high power heavi duty 2-stroke diesels) that are assembled with customizable number of cylinders - e.g. see here https://www.wartsila.com/marine/engine-configurator . In these engines, your "horsepower per cylinder" will probably have some practical use.

"All factors are equal" in your Q may mean two different things:

6.0L 12-cyl makes 700HP

If it gets V10 and still 6.0L total displacement, this would mean bigger cylinders. If they are of comparable geometry to the initial engine, it will probably output the same 700HP or maybe a bit more, because of the reduced heat loss to the chamber walls. Or a bit less, because of the scale factors (like e.g. valve area growing less than the cylinder volume).

If the above engine gets V10 and proportionally 5.0L (i.e. just removed two cylinders, the crank/camshaft and the fuel delivery system reconfigured accordingly) it will have proportionally less power - just like your 583.33HP. Or a little bit higher, because there are now less cylinders competing for the throttle and exhaust capacity (if the throttle and the exhaust are kept the same).

Then again, all these things are gross oversimplifications because a great deal of factors prevent the simple scaling of the engine design.

• It applies to single cylinder engines, and Petter made more than a few… Also Ricardo made single cylinder engines with the facility of a variable compression ratio. Exists in theory books and has practical use. Commented Sep 6, 2021 at 19:57