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Old 11-09-2012, 10:20 AM   #1
shikataganai
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OMGHi2U 2012 Ram 2500 CNG

2012 Ram 2500 CNG




Back in 2011 Chrysler divulged that they were looking at applications of CNG for their North American market offerings, with a target date of 2017. Well, Fiat/Chrysler is shipping their first for-Americans CNG vehicle now, five years early. (NB: Chrysler, pre-Fiat offered CNG vehicles in the past including Ram vans and minivans, but not since 2003 or so.)

Quote:
Originally Posted by Chrysler
The 2012 Ram 2500 CNG is the only OEM-built compressed natural gas-powered pickup truck in North America.

It is actually a bi-fuel vehicle that uses compressed natural gas as its primary fuel source, but automatically switches to gasoline when the CNG tanks are emptied. In use, the Ram CNG transitions from one fuel to the other with little discernible difference in operation or capability.

CNG-powered trucks offer cost and emissions benefits, using an abundant, domestically sourced fuel, which reduces America’s dependence on foreign oil. CNG lessens the environmental impact of greenhouse gas and reduces smog-producing pollutants up to 90 percent.

In vehicles, CNG achieves nearly identical mileage figures as unleaded regular gasoline.
Note the first line about the only "OEM-built" offering. Ford/Westport and GM/IMPCO offer 3rd party CNG bi-fuel conversions on their 3/4 ton pickups that one can order through their dealers. In contrast, Ram's offering is done all in house (Saltillo, Mexico), for better or worse, with the benefit being that it's serviceable by any Ram dealer.

Key stats, in my opinion:

- Available for sale both to fleet customers and retail customers alike (initially was fleet-only)
- $11k for the CNG conversion option, which is only available on Ram 2500 Crew Cab 8' bed 4x4 models in the ST and SLT trims. In other words, this is a very, very long truck: 260"!
- 18.2 gasoline gallon equivalents of CNG stored in the two 3600 psi filling pressure steel tanks nestled up in the front part of that long bed, with either 8 or 35 gallons of gasoline proper stored in the regular gas tank as well. (I leave it as an exercise for the reader to figure out total range between the two fuel sources.)
- ~12% power loss and 10% torque loss when running on CNG with unchanged mileage on either fuel
- The CNG conversion adds about 730 lbs in total. Since GVWR is unchanged at 8,800 lbs payload dips by that much: 1,420 or 1,580 lbs, respectively, for a base SLT or ST truck. Check off some options and a 7,500 lb curb weight is realistic, which implies that actual payload capacity is more like 1,300 lbs if one respects the GVWR.
- Towing capacity is a bit lower, too, per Ram: between 7,450 and 7,650 lbs based off of a lowered GCWR of 15,000
- Only 4' 8" of that 8' bed is usable after accounting for the CNG tanks and their metal enclosure, which is at least mitigated a bit by the tanks' steel enclosure that can bear an evenly distributed 1,000 lbs, iirc

Update: Alternate stats based on the FGAWR (5,200), RGAWR (6,010), and GCWR (15,000 per this source) rather than what Ram publishes (in other words, ignoring the GVWR):

- based on the axle ratings one should be able carry five 200 lb passengers in the cabin + over a ton in the bed
- towing a 7,000 lb trailer off a weight distributing receiver hitch would also be possible with a light passenger load: the tongue weight would be well within the axle limits, load rating 120+ tires will still be safe and legal, and there'd still be some headroom under the GCWR (15,000 GCWR - 7,000 lb trailer - 7,500 curb weight - 200 lb driver is non-negative).

Does Ram recommend exceeding the GVWR of 8,800? No. Is their recommendation legally binding? No. Only the tire load ratings, GCWR, FGAWR, and RGAWR matter in the eyes of the law, as far as I can tell, and the rear axle has a literal ton (and change) of extra capacity as it sits from the factory.

Sources:

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Last edited by shikataganai; 11-11-2012 at 09:29 PM.
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