That thing got a HEMI?"
Just saying the word makes you feel powerful. Try it.
Feels good, doesn't it? Those motorheads in the latest Dodge commercials
sure think so, anyway.
a heritage dating back to the 1930s, the HEMI engine began life
as a liquid-cooled aircraft engine. Chrysler's engineers had developed
a supercharged and turbocharged upside-down V-16 to battle Rolls-Royce's
Merlin engine, used in the Spitfire aircrafts, among others. The
name came from the hemispherical design of the the cylinder head.
1951, "the dual rocker" 331 c.i.d. motor appeared in Chrysler
cars. The theory behind the motor (and any motor) was that the easier
an engine breathes, the greater its volumetric efficiency and the
more power it produces. The hemispherical combustion chamber design
allows large valves to be located across from each other instead
of side-by-side, which creates cross flow and free flow between
the intake and exhaust ports. What that means is a more complete
burning of the air/fuel mixture coming from a central spark plug,
located close-by. The design also minimized heat loss, which in
turn, means more energy. The name "hemispherical" comes
from the fact that the smallest amount of space that can contain
a given volume is a sphere. A hemispherical combustion minimized
the surface area, thus minimized heat loss.
considered to be a great engine, the 180 hp FirePower V-8 would
last in production for only eight years. At the end of its run,
it had grown to be a 392 and put out 390 hp. A racing version was
tested in 1952, but was banned for use in the Indy 50 because its
speed would outrun the rest of the field.
HEMI made other showings, such as the 276 c.i.d. used in DeSotos,
and later, a 241 c.i.d. "Red Ram" used by Dodge
from 1953 through 1957. This model finished its production life
as a 325 c.i.d.
the one HEMI that everyone thinks of first, was of course, the 426
Race HEMI. Former models were dropped from production because of
their complex (read, expensive) design compared to their competition.
Instead, Dodge was making simpler engines bigger, despite being
less efficient than their predecessors. But by the early 60's, Chrysler
was losing too many races at the track. Their NASCAR dominance of
yesterday had waned and they were eager to regain the top position.
What would get them there was the HEMI. The 426 c.i.d. was built.
The race version featured high-flow heads, tubular headers, a potent
12.5:1 compression ratio, and a single, four-barrel carburetor.
Plymouth and Dodge once again became top finishers, proving that
what won on Sunday, sold on Monday.
Fast forwarding to 2003 (model year, anyway), Dodge has re-introduced
the HEMI motor. According to the folks at Dodge, the new 5.7L HEMI
Magnum V-8 is less expensive to build than an overhead cam engine,
but produces comparable power. Learning from the technological advances
over the last few decades, the new HEMI uses aluminum cylinder heads
to reduce weight, fuel injection and electronic throttle control,
and two spark plugs per cylinder and coil-over-plug ignition to
improve combustion efficiency even further. It also uses a high-mounted
camshaft to shorten the pushrods and stiffened rocker arms.
why the long history lesson on the HEMI? Well, in case you've been
living under a rock lately, Dodge's new 2500 and 3500 Heavy Duty
pickups now feature the HEMI as the standard engine. Not only that,
but the HEMI is also set to be available in 2003.5 Ram1500 pickups,
Dodge Durango and possibly even other models, including cars,
in the DaimlerChrysler lineup.
nearly as large as the big blocks of old, the new HEMI is a 345
c.i.d. engine. The eight cylinders (16 valves) run a 9.6:1 compression
ratio and crank out 345 hp (5400 rpm) and 375 lb.-ft of torque (4200rpm).
This represents a 41% power gain and 12% greater torque than the
5.9L Magnum V-8 it replaces. See the chart below to see how this
compares to the other gas-burning motors on the market today.
||Dodge 5.7L HEMI V8
||Ford 5.4L V-8
||GMC 6.0L V-8
||GMC 8.1L V-8
||Dodge 8.0L V-10
||Ford 6.8L V-10
||345 @ 5400 rpm
||260 @ 4500 rpm
||300 @ 4400 rpm
||340 @ 4200 rpm
||305 @4000 rpm
||310 @ 4250 rpm
||375 @ 4200 rpm
||250 @ 2500 rpm
||360 @ 4000 rpm
||455 @ 3200 rpm
||440 @ 2800 rpm
||425 @ 3250 rpm
||345 cu. in.
||330 cu. in.
||364 cu. in.
||496 cu. in.
||488 cu. in.
||415 cu. in.
the chart, each manufacturer's engines horsepower and torque peak
at different rpm ranges, so without actually driving each one in
a comparable truck, it's difficult to say which would be the "best"
motor. If we simply look at the peak values alone, you can see the
HEMI is quite the leader in the V-8 range in horsepower and second
only to the big block GMC engine. The V-10s, of course, are the
torque monsters and beat all, but the HEMI is near the top of the
class once again in the V-8s. Where the HEMI is the big winnerl
is in the all-around numbers, and being a smaller motor than the
V-10s means less of that recommended 89 octane will be purchased
each time you visit the gas pump. Where the HEMI does get outclassed
is in the towing realm, where the diesel motors rule the landscape
with their massive 500+ torque values. But we're talking about gas
engines here, aren't we?
2003 Dodge Ram Heavy Duty Pickups (click
photos for larger views)
So all this brings us to the reason we're here today - the Dodge
Ram 2500HD. In 2002, Dodge began the full-line revamp of the Ram
truck line. For 2003, the Heavy Duty line (2500 and 3500 series)
get their make-overs. The ladder-type frames are completely new
and unique, though similar to the 1500's design. Using hydroformed
"box" sections that are far stiffer than previous designs,
the frames are now stronger, contributing to better steering and
the 2WD versions use a new rack and pinion steering design, the
4WD versions use a redesigned recirculating ball steering setup.
The result is much better steering feel, especially when coupled
with the new 17 x 8 inch wheels. The 4WD Rams have a 13.4:1 overall
steering ratio and 2.75 turn lock-to-lock. Though not nearly as
tight a circle (what is?) as GMC's Quadrasteer trucks, the new Rams
are much more maneuverable than previous models - especially when
in tight spots.
the new frame resides one of four available transmissions, those
Behind the tranny
you have your choice of two new transfer cases - either the NV271
or the NV273. The manual shift NV271 is standard on the ST and SLT
models, while the electronic shift NV273 is optional with the SLT
trim and standard in Laramies. Low-range on both cases is 2.72:1.
Manual, 5-Speed Overdrive (standard. with 5.7L and 8.0L V-8
and 5.9L diesel)
Manual, 6-Speed Overdrive (standard in 5.9L High Output diesel)
Automatic 5-Speed (optional with 5.7L HEMI)
- 47RE Automatic
4-Speed Overdrive (optional with 8.0L V-10 and standard output
the weight of a full-size pickup is a daunting task and the new
Heavy Duty Rams feature a new suspension system in the 4WD versions.
The front suspension is a modified version of the five-link, coil-spring
suspension used on previous HD Rams with a new front beam axle.
Clearance below the axle is 8.7 inches.
rear suspension is common to both 2WD and 4WD models and uses longitudinal
leaf springs, lengthened three inches from the 2002 versions to
improve ride quality. The 2500's two-stage springs have three leaves
for normal loads and an additional leaf for heavy hauling. The rear
box section was also widened to create a wider rear spring span,
which also helps combat lean during cornering. These changes actually
eliminated the need for a rear stabilizer bar.
axles also adorn the new Rams. The 2500 series' axles use a 10.5
inch ring gear (11.5 inch on the 3500) in the rear and a 9.26 inch
in the front. These big-boy axles help the Rams get a best-in-class
towing rating in the 3500 diesel models (12,000 pounds). Upgrading
the standard 3.73:1 axle ratio to 4.10:1 nets an additional 2,000
pounds of towing capacity. 13.9" disc brakes with ABS are at
all four corners.
to the Test Truck --->>>