Diesel Smoke--Dangerous Curves by Jim Elder Trucking Editor There is an old country-western-trucker song by that title. Seems that this driver was in a hurry to get home to his lady, but the curves in the road were not the only hazardous curves he had to overcome. He kept the pedal to the metal, however, and pushed that diesel down the road. Until the 1973 fuel panics, diesel engines were mostly used in commercial trucking, agricultural machinery, and industrial applications in this country. Gasoline shortages then encouraged an outbreak of diesel marketing. Diesels came and went for a while after that. Just when you thought the world was safe from diesels, however, Dodge dropped the 5.9 liter Cummins six-cylinder into their heavy-duty pickups. With only 6 percent of the pickup market share, nobody noticed, except a few people who towed big horse trailers, fifth wheels, and heavy travel trailers. Then came the new Dodge Ram pickups, with the available Cummins turbo diesel engine. Bingo! In 1996, Dodge moved into a 20 percent market share position and close to 61,500 of the 369,073 Dodge trucks sold were diesels. Is this another craze? Should you consider a diesel in your next truck? There are two easy answers and a third hard one to that question. 1. If you hate that rattle/gargle sound, or the characteristic odor of diesel fuel, do not buy a diesel, even if it makes otherwise perfect sense to choose a diesel. Even if it costs you money or performance, do not buy a diesel. You will hate it every time you hear or smell it. 2. If you find yourself humming "King of the Road" or the aforementioned "Diesel Smoke--Dangerous Curves" and wish you could sit at the "Drivers Only" counter at the truck stop, buy a diesel even if it makes no sense at all. Even if it is a waste of money. Even if your wife hates diesels. She may hate you, but follow your destiny. 3. Hard answer. If you don't fit either of the above categories, if you want to consider a diesel purchase rationally, we should first dispel a few myths and half-truths. Cold-weather starting. Modern diesels will start in the winter. With today's engines' intake air heater systems and/or glow plugs, blended fuels, and block heaters, starting is not a major consideration. In fact, most of the trucks in service on Alaska's North Slope are diesels. They plug them in (engine heaters) all winter, but they also do that with the gasoline models. Noise and smell. You should never notice any odor inside the cab, and the sounds (inside) will not drown out the stereo, or even normal conversation. Fuel availability is no problem. Some mini-marts don't sell diesel fuel, but they are mostly snack food stores. You should buy any fuel--diesel or gasoline--from outlets where high volume is some assurance of fresh, clean fuel. Long life. Of course, your experience may vary, but diesels are reputed to last almost forever. Properly maintained--and with diesels that mostly means clean fuel, air, and oil--diesels do often run two to three times the miles of comparable gasoline engines. Maintenance costs are usually lower in the long run--fewer things to check, tune, and replace. If you are still interested, let's cut to the core: economics and performance. They go together. If you haul or tow heavy loads, you'll have a hard time matching the low-end grunt of a turbo diesel. And speaking of turbos, if you live, work, or play in high altitudes, that turbocharger can be worth every extra buck. A turbocharged engine cannot read altimeters. The whole world is virtually sea level to a turbo. Along with that power, depending on driving conditions and models, modern diesels often offer better mileage than gasoline engines. I get a consistent 15 mpg in hard mountain driving with a ton of camper aboard. The same rig with a gasoline V-8 averaged only 8 mpg, and struggled up the hills at higher altitudes. (Might as well dispel another myth--"peaky" diesel performance. Non-turbo diesels usually have a narrow "power band" which requires more shifting. Not true of the Cummins diesels.) The initial cost of buying the diesel option will boost the base price three to four thousand dollars. You will get some of that back at trade-in, but those bucks are tied up, and probably costing interest payments, while you drive around enjoying that great mileage. I've crunched the numbers clockwise, left-handed, and with various combinations of fuel costs, oil costs, diesel engine option prices, and daily horoscopes. What comes up often are odometer readings of 60,000 to 100,000 miles before any financial advantage can be realized from the higher diesel engine price. Bottom line is that you have to roll up long miles before you make any money with a diesel. Owners who trade every two or three years, or use their rig seasonally, might actually be money ahead with a gasoline engine. Back to that song title for a parting shot. The truck dealer will probably not mention engine braking. Truckers know about engine braking, that diesels like to run free down the hills. Without getting too technical, it works like this. Gasoline engine speed is metered by air flow. When you let off on the throttle, air is restricted, and also fuel. The result is high vacuum, and the engine acts as a brake. Commonly called compression braking, it is actually vacuum retardation. Diesels breathe freely, all the time. Speed and power are a function of fuel injection. Letting up on the throttle restricts fuel, but not air--that engine is still breathing deep--running free. Downshifting has some, but minimal, effect on this free-wheeling. Commercial trucks use exhaust retarders, sometimes known as an exhaust brake, to build up cylinder pressure and subsequently engine retardation--braking. Total blockage would blow up the exhaust system and perhaps the engine, so some of that pressure is bled off. That's the loud "brrrraaaapppp" sound you hear when an 18-wheeler is descending a grade. Retarders are available for pickups. Prices range from $750 to $1,250, plus installation. Any diesel buyer who hauls heavy and drives down hills might consider factoring in that extra cost. Look at it this way. After remortgaging your home to buy that bass boat and trailer, you then plunk down whatever it takes for PFDs, fire extinguishers, and perhaps a GPS to get you home in a fogged-over lake. Ram Cummins Turbo Diesel even has its own owner's club. If you fit in category "2" above, you need to be a member. Call the Turbo Diesel Register at 770-938-0711. Copyright 1997 Jim Elder. All rights reserved.