Driving Caterpillar's New 6 25-hp C15
Heavy specs for heavy hauling includes the most powerful truck diesel now on the market.
Tom Berg
Equipment Editor
Some people buy Big Power engines for bragging rights, but for others it makes operating sense. A prime example: The extra heavy loads hauled by Catom Trucking Inc. in the Chicago area prompted owner Tom Stellman to order what turned out to be the first 625-hp Caterpillar C15 installed in a truck, according to the engine and vehicle builder.
Cat announced the C15-625, with 2,050 lbs.-ft. of torque, in March, and began building it in mid summer. It's the most powerful production truck engine on the market and maybe the strongest ever, unless you include mills hopped-up by diesel hotrodders, but those engines wouldn't last long with the service Catom sees.
"We don't run into a lot of grades around here, though we do hit some in Wisconsin and other places we go," Stellman said. "But we do run heavy, and that's where the power helps."
Rugged tractors and multi-axle trailers are heavy to begin with and most loads are oversize and overweight with gross combination weights regularly well above 100,000 pounds and sometimes exceeding 200,000. Catom is an all-Kenworth fleet and is becoming all-Cat, too, its people said.
In order to test drive a fancy Kenworth W900L with a Six and a Quarter Cat, Stellman lined me up with Ron Zarndt, who not only drives one of the two 625-horse tractors in the fleet, but also spec'd them. He showed me a typical day's work that for him started at 4:30 that morning, three and a half hours before I reported in. He had already hauled one load, so some dust marred the KW's glossy black paint but didn't dim its bright-metal trim, which glinted in the morning sun.
His tractor pulled a Talbert three-axle lowboy with a hydraulic gooseneck; the KW has one liftable pusher axle, which we'd need for the second of two loads we hauled. The first was a Rome 89 wheeled pull-scraper - called a "pan" by local construction people - which weighed about 60,000 pounds.The second was a John Deere 450LC tracked excavator weighing 105,000 pounds.
Zarndt said he's been hauling machinery since he was 18, so he loaded the scraper and excavator fairly quickly. Securing them to the lowboy with stout chains and come-alongs, then attaching red flags and yellow banners, took about as much time as maneuvering the bulky equipment aboard. Both were about 12 feet wide and thus had to be carried over city streets and state highways because booths on the Illinois Tollways in suburban Chicago are too narrow for the loads to squeeze through.
All the stop-and-go meant a lot of transmission shifting because Zarndt had spec'd an Eaton Fuller Super 18-speed. But he said he doesn't split any of the nine main gears while running empty, because the engine has plenty of power over a wide RPM band. I split some gears while hauling the scraper, but it wasn't really necessary because its weight wasn't much more than a load of freshly iced lettuce rolling dripping wet out of California's San Joaquin Valley, where a piddling 460 or 475 horses in your typical sleeper-cab tractor pull just fine.
With all respect to long-haulers, this rig is more serious than what they run. In addition to its hefty powertrain and pusher axle, the W900L tractor has a two-speed tandem, double frame rails, a wet kit to operate the hydraulic gooseneck on the lowboy, and polished aluminum headboard and tool boxes to tote chains, binders, bungees, flags and other stuff needed in this business. With 250 gallons of fuel the tractor weighs about 26,000 pounds, Zarndt said. The trailer on this day weighed about 24,000 pounds with just the standard tridem at the rear of its 53-foot-long frame. It can be outfitted with stinger axles and other gear to boost its capacity and tare weight.
While loaded with the scraper I found that skipping Low gear and starting in 1st was sufficient to get us moving on anything but an upgrade, and on slight downgrades I could start out in 2nd or 3rd if I let it roll a little. With the heavier load, Zarndt switched the Spicer dual-range tandem into low. This changed the differentials' gear ratio from 3.70 to 5.04 so we could really pull. Later, Tom Stellman said that extra gearing and the long driveshaft all sap power and reduce horsepower at the wheels. So the Cat's 625 horses are reined in somewhat.
Anyway, I quickly got accustomed to the 18-speed and remarked on how well Kenworth sets up its manual transmissions. Still, I did get lost once in the tranny as I climbed a short hill, and shifted by mistake from 2nd on the low side to 5th in high. Even the Cat wasn't strong enough to recover from that and I had to start over from Low gear. "How red's my face?" I asked. "Pretty red," Zarndt said.
Otherwise the big Cat propelled us smartly away from intersections and traffic slowdowns, and kept us moving well at highway speeds on the few open roads we used. "I can usually keep up with any of the trucks around here," Zarndt said, "but some of the rock jockies will yell (over the CB), "Jeez, whatcha got in there?' and I'll say, "Oh, it's a turned-up 290.' "Yeah, sure!' they'll say."
He tended to rev the Cat toward 1,800 and 1,900 rpm, whereas I tried to keep it closer to 1,600. Either way, it pulled strongly and smoothly, from about 1,100 all the way to 2,100.
It took about 45 minutes to haul the scraper from a housing site near Geneva - Catom Trucking's home base west of Chicago - to a commercial development near O'Hare Field. After unloading the machine at the job site, Zarndt directed me to another site nearby where he loaded the Deere excavator.
The big machine was a dirty yellow (why don't they at least stripe "em John Deere Green?) and its engine had a blown turbo, so great clouds of white smoke poured from its rusted stack as it crawled feebly onto the lowboy. We took it to a Deere dealer in South Holland, near the Indiana line, again using streets and secondary highways. We'd build up speed briskly, then quickly slow for traffic and sharp turns and stop for red lights, over and over and over.
This was work. Rowing through the gears wasn't bad once I got the feel for this tranny and began clutchlessly float-shifting. But after a while I wished Zarndt had ordered the Fuller AutoShift that he had considered. "I knew there was an 18-speed AutoShift," he said. "I never drove one, but we asked the dealer (Wisconsin Kenworth in Milwaukee) about it and he told us that it might not be the right thing for this application."
AutoShifts can be temperamental, but sure are sweet when they work, I told him.
Shifting aside, this run was tedious because the excavator's low-slung tracks hung out about a foot and three-quarters on either side of the 102-inch-wide lowboy. I constantly watched them through the mirrors to be sure I didn't clobber anything or anybody. Following Zarndt's coaching, I hogged two lanes on narrow boulevards and where bridge abutments and other obstacles were close to the travel lanes, no doubt irking motorists who tried to pass on the left or right and sometimes succeeded. But some motorists and all truckers gave me breaks when I needed maneuvering room, and I'd wave a thanks each time.
It would've been more work except for the Cat's strength and the Kenworth's comfort. I knew there was always plenty of power and torque no matter what the situation. Meanwhile the KW looked good, rode nicely and maneuvered fairly well, even with a long 265-inch wheelbase, big hood and forward-set steer axle with its limited wheel cut.
Specs include the Extended Daycab option, so there's an extra five inches of roof height and six inches at the rear of the cab, providing stretch-out room and space for storing supplies. Zarndt keeps a ream of paper for the fax machine that's mounted on a pull-out frame beneath the passenger seat; that eliminates hunting for a fax to get hard copies of permits from state and local authorities. The fax is wired to a mobile phone, and he carries two others, so he's not a hard man to reach. He got several calls during our runs and told colleagues that he had a chauffeur this day.
Yakking with him while shifting and watching traffic and the load in the mirrors kept me from paying much attention to the gauges, so I can't say a lot about engine conditions and such. Zarndt pointed out that the boost gauge shows as much as 58 psi from the Cat ACERT's double turbochargers, which obviously push a lot of air but remained quiet. The engine stayed fairly cool, though the fan kicked in a lot as outside temperatures climbed into the 70s.
The turbos worked feverishly as we climbed the one steepish grade on our meandering route, a short stretch of 4 or 5% on a state highway. With that 105,000-pound excavator aboard, our GCW was about 155,000 pounds, yet rpms stayed at 1,400 to 1,500 as we ascended the hill at a steady 35 mph in 6th-low.
I probably could've accelerated if I had downshifted to raise revs and catch more horsepower, but I let torque do the job. Speed built quickly as we crested the grade and I quickly upshifted toward the top (18th) ratio, where the engine spinned about 1,650 at 60 mph (with the tandem still in 5.04-low, remember).
We proceeded through one town after another with a few rural stretches between them, and I had no idea where we were. "Are we almost there?" I kept asking Zarndt, and just like a patient daddy he repeatedly answered, "Almost." That went on for the last half of the two-hour run, and I was a tad tired by the time we got there. "You're driving back," I told him after he unloaded the smoking Deere, and he did. He used the tollways, which were wide enough for our empty lowboy, though rush-hour traffic made the run home no picnic.
"This is the nicest truck I've ever had," he declared as we pulled into Catom's compact terminal about 6:30 that evening. "And I expect it to stay that way for a while."
Another Catom driver who's assigned an identical tractor no doubt feels the same way, as I would if I were lucky enough to be assigned a rig like this.
Cat calls its C15-625 its latest King of the Hill - a title once held by a 3406E-550.
And the title's fitting - with or without hills.
Drive Tests continued...
