Edge, along
with Diesel Dynamics, built three engines for test and development purposes.
All are based on the Cummins 5.9-liter inline-6 but only the engine blocks
are original equipment. Custom crankshaft and rods were sourced out but
Lehman won’t disclose stroke or rod length. Custom pistons that
“are not flat top” complete the rotating assembly. The cylinder
heads—especially the valves—received major work to open up
air flow. Edge also had custom camshafts ground to their specs. Currently
stock injectors are used but Lehman says, “We feel there’s
more potential with something else.” The injectors are driven by
instructions from an Edge-calibrated engine management computer.
Twin turbos from Diesel Dynamics force-feed air to the cylinders to
keep up with the extra fuel, according to driver Keith Lockliear. “We
stuff a bunch of fuel to the engine, figure out how to feed it even more
fuel, then play with the turbo and boost till we get what we call ‘mega
mental’ amounts of air and boost to burn all that fuel.”
The diesel is backed by a Lenco 5-speed and special clutch setup. A
typical Pro Stock car will launch at about 8000 rpm while the diesel redlines
between 4000 and 5000 rpm. But it offers a ton of twisting power that
can be difficult to tame. In fact, nitrous oxide is mixed with the Chevron
#2 diesel fuel to spool up the turbos on the starting line.
“Nobody
has unleashed this much violence and torque at the starting line. We’re
easily running 50 pounds of boost at the start,” explains Lehman.
“When you let go all at once, the massive torque has an effect on
all the components. One of those things to slip was the turbo rotating
on the flange.”
Although Lehman won’t be specific on any engine technology at
this point, he estimates horsepower at over 1100 and torque at 2500-plus
lb-ft. He acknowledges exhaust gas temperatures hover around 1450 degrees.
At this writing in late September, the truck had yet made a full pass
under power. Edge is wandering in uncharted territory when it comes to
clutch and chassis setup with the diesel engine. So far the truck had
a best of 9.77 seconds when shutting off at the eighth-mile marker, but
the team has notched a 60-foot time of 1.22 seconds. More tests were planned,
including full passes, in October, and the truck is expected to appear
at the SEMA show in November where more details will be released on the
engine technology.
