What's the point of high octane fuel in non-sport cars?

[Ferrari458Italia]

I understand sports cars and race cars requiring high octane (more ponies). But why would Lexus require premium in the LX when it's basically the same car as the Land Cruiser which requires 87?

 

[Venom800tt]

Compression ratio is one of the main reasons. High compression engines, even when not in actual performance cars, generally tend to need higher octane fuel to prevent detonation. Now, not all high compression engines are designed for higher octane fuel. Some, like the Mazda 3 Turbo can run either, the ECU limits power to prevent detonation when running low grade fuel.

 

[wfooshee]

Your phrase "high octane (more ponies)" shows a lack of understanding of what octane is. Octane is not power, it is resistance to compression ignition. If the fuel ignites under compression, before the spark, you get engine knock. High octane fuel is not "more powerful" fuel. The knock resistance of high-octane fuel is needed by high-compression engines, which use that higher compression to produce more power.

Putting high-octane into an engine does not make a regular engine more powerful, but putting regular gas in an engine that requires premium can eventually destroy it. My S55 owner's manual even said extended use of regular fuel would void the warranty.