behind one, you can spot a diesel equipped HD from a distance.
aperture is over 5-inches in diameter. You could bake a potato in this
thing. The tip is actually welded on the exhaust about a foot from the
back. It overlaps a smaller 3-inch tailpipe to create an opening that
allows ambient air to quickly mix and cool off the hot engine exhaust
from the emissions controls– so you don’t burn the paint off
the car next to you at a grocery store when you park.
wait to see the massive chrome tips that start showing up in the aftermarket!
include new seven hole common rail piezo electric injectors that are safe
for use with ULSD fuel and lower noise levels by precisely and variably
injecting fuel multiple times during a single combustion stroke.
The GM trucks
also use improved glow plugs in “park warm up mode” that heat
up faster than Ford's PSD glow plugs and Dodge’s ambient air intake
heater on the Cummins - saving up to seven seconds starting the engine
over conventional glow plugs in extremely cold conditions.
All of this engine technology requires computing power. A new 32-bit
controller manages the fuel injection, fan, and oxygen levels to precisely
control engine temperatures, increase efficiency, and slightly raise fuel
to Gary Arvan, Chief Duramax Engineer, the LMM carries roughly two to
three times the computing power over the original 2001 LB7 Duramax. And
to meet even stricter 2010 emissions requirements, Arvan expects to see
computing power jump another two-fold over the 2007 engine.
Even more amazing, while improving fuel economy and emissions, GM has
raised the power ratings on the Duramax to a class leading 365 horsepower
and 660 lb-feet of torque that can propel a regular cab HD from 0 to 60
mph in the low seven second range, according to Garvan.
The net result
- as a passenger for this part of the ride, it was incredibly difficult
to tell we were in a diesel given rapid acceleration runs from a dead
stop and GM’s attention to interior noise reduction and very low
levels of clatter at rest and under load.
noise, vibration, and harshness levels are a major step up over the respectable
NVH levels in the previous GMT800s.
thing the Duramax needs is a larger fuel tank. The 26-gallon tank, standard
on short beds, provides a range of only about 400 miles. Long beds get
a 34-gallon tank. Assistant GMT 900 vehicle chief Jully Burau responded
to our questions about the relatively small range with the cryptic response,
“to stay tuned.”
A large portion
of this ride was on I15 at speeds up to near 80 mph. For such a massive
vehicle there was very little wind noise to impede conversations between
front and rear passengers, thanks to better aerodynamics and a stiffer
frame that allows for closer positioning of the bed and cab to reduce
the gap between these components.