s a f e t y   &  o p e r a t i o n s

Spec'ing The New Powertrains

Engines of October will change some (but not all) of what you choose.

ED THOMAS
CONTRIBUTING EDITOR

      We live in interesting times. Aside from all the disconcerting world news, we are faced with the prospect of serious changes in the diesels we'll see after Oct. 1. Most will have exhaust gas recirculation or other equipment to cut tailpipe emissions to the government's satisfaction. The new engines will cost more to buy and operate, but we don't yet know exactly how much.
      If you're out to spec a new truck, you may have questions about the engine and other powertrain components that the sales guy can't exactly answer, yet. The final word on a number of things may not come down until the end of August. But we do know about some of the effects of the Engines of October and how they'll affect your spec'ing choices.
      Some good news is that from the flywheel rearward, nothing should change, except with Mack (see below). There are no new torque forces coming from the engines, so you will not need a tougher clutch, transmission, driveline or axles. If you're a power freak, you can lighten up a bit, because the biggest diesels now on the market will disappear for a while.
      Caterpillar and Cummins are dropping their 600-horsepower, 2,050- pounds-feet models, Cat's C-16 and Cummins' Signature 600. The strongest Cat after Oct. 1 will be a 525-hp C-15, and the strongest Cummins will be a 565-hp ISX. Each will make no more than 1,850 pounds-feet of torque, and most will have 1,750 pounds-feet or less.
      If you're a Detroit Diesel loyalist, be aware that its 14-liter 500-, 550- and 575-hp models will be dropped for a few months. The 14-liter Series 60 will reappear in spring, probably as a 500 with 1,650 pounds-feet of torque. Detroit engineers tend to classify things according to torque rather than horsepower, and are figuring out which displacement to use for 1,550-pound-feet models. It might be a 14-liter or a 12.7-liter, or maybe both.
      Volvo's 12-liter V-Pulse diesels will not change in torque output or operating ranges, so driveline components should not be affected. As now, V-Pulse will have a pre-heating system that will speed warmups from dead-cold starting, and has other uses. Ask about it.

Consider Long-Life Parts
      Torque capacity of your drivetrain components mated to post-Oct. 1 engines need be no more than now, or perhaps less than what you're used to spec'ing. That might save you a few hundred dollars, even if you weep at the idea of running with lower horsepower.
      You might take what you save in buying lower torque capacity and spend it on low-maintenance parts. For example, Spicer says its Life series of drivelines can be ordered with XL kits that include U-joints with permanently lubed splines. These and other features extend times between maintenance intervals and, as before, stand up to whatever punishment the engine can send to them.
      As for driveline components behind Cat, Cummins, Detroit and Volvo engines, you just need to do as you now do: Be sure that they are beefy enough to take whatever torque the engine will produce. And you should upgrade driveline components if you plan to uprate your engine later. There will be some changes among each builder's engine "families" in what can and cannot be uprated; check this out before you order.

Changes To Maxidynes
      Mack has made several changes in its 12-liter Maxidyne diesels. The current 300-hp rating's torque drops from 1,450 pounds-feet to 1,250 pounds feet (but don't fret yet), and there are new 335- and 370-hp ratings. Also, the current operating range of 1,000 to 1,750 rpm goes to 1,700 to 2,100 rpm. The new rev range is not only higher, but shorter by 250 rpm. So Mack will set you up with one more transmission gear.
      A pair of new 6- and 7-speed gearboxes will be mated to the Maxidynes instead of the current 5- and 6-speed offerings. Like the current transmissions, the new TM308 and TM309 boxes have two additional low-low ratios handy for off-road maneuvering or starting out on steep grades.
      With one extra ratio to run through, the new, less torquey 300-hp Maxidyne performs every bit as well as the current stronger model, Mack engineers insist. They say customer drivers who tried the new setup liked it better because it felt gutsier.
      Cruising revs also climb in the new Maxidynes, from 1,500 to 1,700. Meanwhile, the overdrive-high gear on the new transmissions stays about the same. So the truck needs a "faster" (numerically lower) axle ratio.
      It's important that the truck be set up right and driven correctly, or the Maxidynes will not deliver the performance or fuel economy they're meant to, engineers say. Sales people should know about all of this when you go talk to them, as applications engineers have sent out training materials.
      Come October, Maxidyne diesels will have Mack's internal EGR system. This, as you may have heard, is a simple form of EGR that works well in vocational trucks, like dumpers and concrete mixers. Econodyne and MaxiCruise versions of the 12-liter diesel go primarily in highway trucks, so will get cooled EGR, which is more complex but also more fuel-efficient at highway speeds.

Cooling System Changes
      Heat rejected from EGR systems has to be handled by the radiator and good air flow, though recent testing shows it's not the big problem that truck builders once feared. Some of the heftier EGR'd diesels will need bigger cooling packages, but engines with more modest torque and horsepower won't need them.
      For example, Detroit models that produce 1,550 pounds-feet of torque will require a radiator with 1,350 square inches instead of the current 1,200-square-inch unit. But models making 1,450 pounds-feet or less can stay with the smaller radiator. The bigger radiator will weigh a bit more, enough to cancel out the 50-pound weight reduction Detroit has achieved for its 12.7-liter Series 60.
      Mack is installing an "inverted" radiator-charge-air cooler package, with the cooler behind the radiator instead of in front of it, on some Vision tractors. Tests show it just works better that way, but not on all truck models. On other models it's using a fan "ring" very close to the fan blades' tips. This funnels air more efficiently than a wider-diameter shroud.

Cat Converters
      Caterpillar's post-Oct. 1 Clean Power diesels will not use EGR, but, among other things, will get exhaust aftertreatment to soak up NOx. This is a catalytic converter combined with the muffler. The unit must be installed a certain distance from the turbocharger to ensure proper operation; and larger engines will need more ceramic-coated material.
      These requirements limit how the exhaust system can be configured, and truck builders have to design around them. Peterbilt, for instance, has told its dealers that dual stacks with a pair of 10-inch-diameter converter-mufflers will be required with some truck and engine models. An alternative is a single 14-inch-diameter converter-muffler, but it has to be horizontally hung.
      Some customers do not like horizontal, frame-hung exhausts, partly for looks (they like chromed stacks) and partly because the muffler is too close to the road where splash and spray can eat it up and debris can whack it. This becomes more serious when one realizes that a converter-muffler may cost $1,000 to replace vs. a hundred or so bucks for a simple muffler.
      And you can't just yank off the new system and go to a "straight" pipe, whose bellowing note is cherished by some guys and gals. The converter-mufflers are needed to clean up the exhaust, so removing them will be illegal. It's possible that separate catalytic converters will become available on the aftermarket, and then the original Caterpillar devices could be yanked off, but don't count on it.
      Cat's Clean Power engines are only temporary. The first of its ACERT (Advanced Combustion Emissions Reduction Technology) engines — a new 9-liter C-9 — is due out in January. Big-bore ACERTed models will begin coming out next April.
      Cat engineers planned a second aftertreatment device — a particulate trap — for the bigger ACERT engines, but recently told truck makers that it will instead use double turbocharging and double aftercooling. This would result in higher heat under the hood, and require larger radiators, like those for competitors' EGR engines. Stay tuned for more info on this.

Less Model Choice
      Truck manufacturers had to rethink some of their engine and model offerings for various reasons. Kenworth, Peterbilt and International are dropping Detroit because it is owned by Freightliner's parent, DaimlerChrysler. Freightliner meanwhile is dropping most Cummins engines to pare down its engineering expense.
      Engineering in the various changes to accommodate the new engines is expensive, and some truck makers are drawing the line. In some cases they will limit changes in radiators to only certain models, so you may have to go to a different model to get the engine you want.
      At least one model will go away. Freightliner says it will stop producing highway versions of its venerable FLD120, so you'd have to go to a Century to stay in the Freightliner family. It will keep the FLD120SD, the version used in construction and other severe-duty applications.
      Interestingly, the U.S. Army is buying thousands of Series 60- powered FLD120SDs in various configurations, and these will continue in production into 2007 without emissions-based changes. Freightliner explains that the Army gets an exemption from exhaust emissions regs because the contract was placed in late 2001, well prior to the October 2002 deadline. Make you want to join up?

Imports Have Advantage
      You can stay a civilian and still avoid EGR if you're willing to try an imported diesel. Because the EPA's Consent Decree affected almost no foreign-built diesels, they will not need to use EGR or anything else until January 2004. So you could spec a medium- or heavy duty Mercedes-Benz diesel in a Freightliner, Sterling or Western Star.
      In medium-duty trucks, all Japanese imports will not need EGR. Mack's Freedom will. Most domestic trucks with Cat and Cummins diesels will have EGR. International will use EGR on only one of its diesels. General Motors' Duramax diesels don't need EGR until 2004.
      So, take your spec'ing notebook and go figure. Most of your pondering will be under the hood. Don't let it fall on you.