PDI Big Boss Stage 1 Turbo for CAT 3406E | C15PDI Big Boss Stage 1 Turbo for CAT 3406E and C15 Key Features: 78mm Billet compressor wheel 360 degree thrust bearing 1. 32 AR Exhaust Housing Improved throttle response Cooler exhaust temperatures The PDI Big Boss Turbo is made as an upgrade for most CAT engines with serial number prefixes 5EK, 6TS, 1LW, 1MM, 6NZ, 7CZ, and MBN. Quicker spool up time gives you better throttle response and can help with fuel economy. Features our HSM type exhaust