Texas awaits next Duramax engine

Observers of the US diesel engine scene are waiting for this week's Texas State Fair which opens 30 September to see how General Motors achieves 445 bhp from its 6.6-litre V8 Duramax.

The figures for output and torque could be found on the General Motors’ GM Powertrain site until the site was hastily withdrawn but has recently re-appeared.

The figures for the next-generation L5P 6.6-litre turbocharged V-8 installed in the Silverado HD and Sierra HD were clear to see – 445 bhp (332 kW) at 2,800 rev/min and 910 lbft (1,234 Nm) at 1,600 rev/min.

This gives the L5P a 5 bhp edge over the 2017 Super Duty’s 6.7-litre Power Stroke, and 15 lbft less. The Ford Power Stroke engine, built at the Chihuahua Engine Plant, has a compacted graphite iron (CGI) cylinder block.

So far, GM has revealed only a new two-path intake system for the L5P, allowing it to ingest more air. The 103 x 99 mm bore and stroke dimensions and 16.0:1 compression ratio remain unchanged.

The L5P is made at General Motors’ Moraine, Ohio engine plant. And last December, DMAX, Ltd. announced it would invest $82 million at the DMAX plant for future Duramax diesel engine-related productivity improvements, creating approximately 150 jobs over the next three years at the joint venture between GM and Isuzu, dependent on state and local incentive approvals.

An sum of $82 million is not much in terms of engine plant investments so it will be interesting to see what transpires as the reason for this increase in power. Meanwhile, at the time DMAX stated that less than a year ago, a $60 million investment was made at the plant to make design changes enabling the engines to meet future emissions requirements.