Last month I compared Detroit’s calculated fuel consumption between the marinized 14 liter HK Series 60 and the Pre EGR highway 14 liter HK Series 60. I was surprised to see that despite having a more aggressive camshaft and larger injectors, the marinized 14 liter Series 60 had slightly more efficient fuel consumption numbers than the highway version. My guess? It almost has to be the injection timing.
I’m going to run this test the same way as last month, except this time I’m going to program the Marinized DDEC and the Highway DDEC to run with the same amount of injection timing advance. The goal here is to cancel out any gains in efficiency due to injection timing advance. This way we can look at the differences between the marine Series 60 and the highway Series 60 in terms of their fuel consumption numbers without factoring in the injection timing.
For the second trial, I programmed in identical static timing values in both the marine and highway HK DDECs. This way we can factor out the injection timing differences in the fuel consumption calculation.
The first test is at light load between 1200 rpm and 1800 rpm. Torque output is set to 500 ft-lbs
Highway HK running marine injection timing
Now that we’ve cancelled out the gains due to timing advance the fuel consumption numbers make sense. In general, larger injectors can’t fire as precisely as smaller injectors so some loss of efficiency can be expected. This data suggests that if you need 550 horsepower to climb a hill you’re going to burn less fuel with a highway camshaft and highway injectors than a marine camshaft and injector combination designed for 825 horsepower.
Written Fernando DeMoura, Diesel Control Service LLC.