Feature Caterpillar 3406 Stage 5 CAT 18 ACERT Engine capacity 14.6 litres 18 litres Emissions Meets Stage 5 Older Standards (Tier 3/Tier 4) Power 400-600 hp 600-1100+ hp Application Trucks, construction machinery Mining, marine, heavy industry Technology Modern emissions system (DPF/SCR) ACERT (older generation) Weight/power Lighter, more efficient Heavier, extremely robust