What To Expect From The Next Medium-Range Unimog
Yes, Motor Authority has some neat spy shots of what appears to be a new development of the UGN-series (think U300/U400/U500) Unimog. When it comes to anything other than a brief visual description, the blog passes the buck, saying essentially technical advancements are surely coming -- after all, when are they not?
Thankfully, if you choose to read between some of the lines of Daimler's own press materials from late last year, you have a decent indication of what's in store. Here's a quick run-through of what we can expect from the UGN's first major makeover in 13 years.
New Nose: The UGN/405 broke quite a bit of new ground, especially cosmetically. The upright cab, positioned in a semi-COE position, required virtually no conventional hood – what was left was almost vestigial; a small, tapering remnant that covered only some extraneous driveline accessories.
That’s no longer the case. Early spy shots show a nose that’s longer, taller, and bulkier than before. Judging by the hood’s shape, side air intake, and grille design, it appears as if designers are trying to visually tie the mid-range Unimog to its larger UHN (U3000/U4000/U5000) siblings.
Keen eyes will also note the composite cab is slightly reshaped: a large hump above the windshield provides space for the windshield wiper motors, which were previously located beneath the windscreen.
New Bumpers/Lamps/Connectors: Every spy shot – including a couple of preview photos issued by Daimler itself – show the new Mog boasting headlamps in the bumpers.
Okay, so that’s not exactly news, but this time, the Unimog gleans small, individual projector lamps in lieu of the large, rectangular composite assemblies previously used.
This new, smaller footprint also allows room for front hydraulic circuit connectors to be placed in the bumper instead of at the leading edge of the hood. In fact, the 2014 UGN chassis Daimler showed at last year's Frankfurt show boasted these hydraulic connectors tucked neatly into a square-shaped bumper opening just inset of the headlamps. And, speaking of bumpers, the front bumper gains a tube-shaped surround that incorporates steps on either side of the implement mounting plate.
New Engines, New Emissions: So long, 904/906. Benz plans on offering the mid-range Unimog series with four- and six-cylinder turbo-diesel engines yet again, but in slightly different forms. The OM 904 -- a 4.3-liter I-4 offered on the U300 and U400 -- will be replaced by the OM 934, which is a 5.1-liter turbo-diesel I-4. The OM 906, a 6.4-liter I-6 optional on the U400 and standard on the U500, will give way to the OM 936, a massive 7.7-liter I-6.
Both the 934/936 are DOHC engines, boast new crossflow cylinder heads, four valves per cylinder, and variable cam phasing -- allegedly a novelty of sorts on diesel engines. Power ratings haven't been released, but Daimler says the six-cylinder 936 will broach the 300-hp mark for the first time, and crank out close to 1200 Nm of torque. Considering the high-output OM 906 emitted but 286 hp and 1120 Nm, these represent healthy increases over the UGN model range. Better yet, they're all compliant with Euro VI emission standards.
Predictably, packing this sorts of power -- and these sorts of upgraded SCR exhaust catalyst systems -- requires some pretty heady cooling system modifications. There's apparently some considerable re-work to the radiators (mounted behind the cab steps, since the engine is essentially placed in the middle of the chassis). There's also some revision on the passenger's side of the truck; the fairings that appear to enclose both battery boxes and AdBlue tanks look slick. Still, we have to wonder about heat dissipation -- the new truck isn't any larger than the current UGN (in fact, its length shrinks by 8 cm), and Daimler wants to avoid having the Unimog grow porky and portly. Given those size requirements, there's only so much radiator you can package in so much space...
Carry-over Transmission: Daimler just says the new 'Mog will use the "well-known Unimog transmission." As such, expect the present semi-automatic gearbox with 8 forward speeds and six reverse speeds to remain standard. An extra pair of reverse gears (ideal for Hy-Rail spotter use) will probably remain optional, as will eight crawler and eight low-range "working gears," respectively.
New Chassis? This remains a bit of a mystery. A complete departure from the existing UGN frame is rather unlikely, but Daimler does note the new engines, cooling systems, and emissions hardware do add weight to the mixture, which can negatively affect payload. Expect to see additional lightweight tricks employed throughout the vehicle – Daimler hints at placing “apertures on the frame” (i.e. ‘swiss-cheesing’ mass out of it) and using aluminum wheels, and also says it's fortified the existing portal axles to withstand an increase in power and weight. Daimler says the truck's maximum permissible GVW has increased, but by what margins still remains unknown.
