4.5L Duramax Diesel

4.5L Duramax V-8 Engine Specs& Information

The 4.5L Duramax displayed several innovative features, including reverse flow cylinder heads, a weight saving compacted graphite iron engine block, 72 degree cylinder spacing, and dual overhead camshafts with 4 valves per cylinder. Reverse flow cylinder heads arrange the exhaust path into the engine valley, where the turbocharger is mounted, to improve thermal efficiency and reduce turbo lag. The engine was designed with cylinders at 72 degree separation angles to narrow the engine, likely to increase serviceability and enhance its adaptability into additional applications with more stringent spacial restraints.

A clean-sheet engine design, the 4.5L Duramax would have been designed and produced independently of DMAX, the GM-Isuzu joint venture that has manufactured the flagship 6.6L Duramax diesel since 2001. Much has changed in the segment since GM first teased the industry with its 4.5L prototype, and in reality the 4.5L Duramax was unlikely to meet GM's long term goals with regards to efficiency; the 1/2 ton segment now has three highly fuel efficient diesel options, which include the 3.0L Duramax, FCA's 3.0L EcoDiesel, and Ford's 3.0L Power Stroke.

4.5L LMK Duramax Engine Specs

^[1] - Bore and stroke interpolated using the bore-stroke ratio from the 6.6L Duramax diesel (1.04); provided values are highly speculative and were never substantiated.