Cummins ISX15 Engine

The Cummins ISX15 (later X15) is a 15-litre inline-six diesel available as an engine option in Peterbilt, Kenworth, Freightliner, Mack, and Western Star Class 8 trucks. Offering 400–600 hp and up to 2,779 Nm, the ISX15 dominates the North American long-haul market. The same Cummins short-block is shared across PACCAR's Peterbilt and Kenworth brands, reducing parts inventory for fleet operators.