Honda Ridgeline Trophy Truck
Building a mild-mannered SUT to tackle Baja
Honda Motor Company has nothing to prove in the desert-at least on two wheels. In the last decade alone, factory-backed Honda motorcycle teams have notched nine straight wins in the Baja 1000. It would be hard to count just how many other off-road races have been won by riders astride Hondas, whether factory-backed or privateer.
Yet in 2005, Honda had a different desert-race goal in its sights. Faced with a mixed reception to its all-new Honda Ridgeline pickup, Honda decided to prove its truck's mettle by entering one in the grueling Baja race. Many truck makers over the years have traded on the cachet that comes with south-of-the-border desert competition, and Honda no doubt figured the Honda Ridgeline could get a nice boost by surviving one of the toughest challenges in all of motorsports.
Rather than start a truck-race program from scratch, Honda sought partners with experience in the desert, especially in the area of turning production vehicles into competition-ready machines. Clive Skilton and his son, Gavin, seemed perfectly tailored for the job. Originally with Don-A-Vee Motorsports (which has since become California Race and Rally, or CaRR), the Skiltons have spent some 15 years prepping and racing unibody Jeeps, and Clive now heads the JeepSpeed racing series. Another of Skilton's sons, Darren, successfully transformed Kia SUVs into desert race trucks that weren't just competitive; they notched an impressive series of wins.
Gavin Skilton headed up the Honda race effort for CaRR; and to build the truck he assembled a team of desert-race veterans, including fabricator Jason La Fortune and his crew at Temper Mental Racing.
With its years of experience in race series as diverse as motocross and Formula 1, Honda probably could have fielded a super-exotic, Honda Ridgeline based Trophy Truck and gone on the hunt for an overall win. But that wasn't the point of the exercise; showing off the Ridgeline's inherent capabilities was. So the CaRR truck was entered in SCORE's Stock Mini class, which allows only limited modifications to production trucks.
To underscore the "stock" in Stock Mini, the truck delivered to the team wasn't some stripped, body-in-white shell, but a fully trimmed, ready-for-the-showroom-floor Ridgeline. That meant the team's first order of business was to put the pickup on a strict diet. Out came the truck's interior ("the rear seat weighed a ton," Skilton said), carpeting, sound insulation, airbags and window glass. The Ridgeline's innovative underbed "trunk" was removed in the interest of ground clearance; later, that hole would be filled with one of the truck's two spare tires.
Skilton figured they removed between 600 and 800 pounds from the truck. Most of that weight would be added back, though, with the addition of the rollcage, fuel cell, spare tires, jack and tools, bigger wheels and tires, and so on. SCORE's rules, in fact, call for the truck to race at its "as delivered" weight, "and with everything we have to add to the truck, it probably won't be underweight," Skilton said early in the process.
With much of the truck stripped to the metal, the team found the Honda Ridgeline's unibody surprisingly well put together. "It's strong enough that the rollcage will be there just for safety, and not to hold the unibody together," said Skilton. Honda engineers, in fact, report that the Ridgeline's unibody has 20 times the torsional rigidity of a conventional body-on-frame configuration.
The full rollcage, made from 13/4-inch, 0.120-wall chromoly, provided a cocoon for the occupants and the 26-gallon ATL fuel cell. Downbars front and rear tied into the suspension mount points to give them added strength, while an additional set of bars wrapped around the engine and through the grille to mate with the chromoly front bumper. Later, that bumper would serve as an attachment point for one of several additional skidplates under the Ridgeline.
In a race truck, "the suspension is everything," Skilton believes. "It all revolves around the suspension. No matter how trick the engine is, if the truck can't handle the bumps ...." He left the rest unsaid.
Suspension tuning is one area where the SCORE Stock Mini rules are somewhat relaxed. The truck's original suspension configuration must be retained, and there are limits to the number of shocks used per wheel and to where they can be located (not through the hood or above the bed floor in the rear). Within those parameters, racers are free to modify springs, shocks, and struts.
As it turned out, Skilton loved the stock Honda Ridgeline's handling, praising its fully independent suspension for its carlike ability to stick to the road and handle curves. When it came time to upgrade the suspension, he didn't want to change its geometry at all. The goal instead was to come up with components that would live in the jarring Baja environment, provide a bit more wheel travel and give the truck additional ground clearance.
Skilton turned to King Racing Shocks for help with the componentry. The rear end was fairly straightforward-slightly firmer, taller springs, and 3-inch remote-reservoir shocks fit nicely into the stock location.
The front was another matter entirely. The Ridgeline is fitted with MacPherson struts, and King had never built a racing version of a strut-until now, anyway. By combining off-the-shelf components and custom fabrication, King built prototype struts using 3-inch shock bodies with massive 1 1/4-inch shafts (which are normally 7/8 inch in a 3-inch can); dual remote reservoirs; adjustable spring-mount collars; and coil springs rated at 350 pounds, nearly double the stock rate. "That'll give us the height and strength we need in front" to help lift the truck over obstacles, Skilton said.
The key to making the strut work was a custom-built strut top with a 5-inch thrust bearing. "Everything moves with a front strut," Skilton explained, holding the top of the strut in his hand and rotating its body in a circle. "So our custom bearing cup allows this movement but protects the bearing from dirt and dust."
Because the King struts were longer than stock, their top mounts had to be moved up out of their stock location to triangulated mount points built into the rollcage. The difference in mount height is only a couple of inches, but it made a difference in terms of wheel travel-now 8.5 inches-and ground clearance. Between the new suspension and the nearly 32-inch tires CaRR planned to use in the race, the Ridgeline gained about an inch and a half of altitude between it and the desert floor.
Tire choice for the Honda Ridgeline was a challenge, Skilton admitted. He liked the truck's big brakes-12-inch rotors with dual-piston calipers in front, 13s with single pots in back-but keeping them meant also keeping the stock 17-inch wheels for clearance. And that meant a narrower selection of tires from sponsor BFGoodrich. Compounding the problem was the fact that the rule book was strict about body modifications. No fiberglass fenders or even flares were allowed to clear big tires; only 2 inches could be removed from the fender opening.
Skilton was concerned, too, that even if he could fit 33s under the truck, the driveshafts, differentials, and wheel hub assemblies might not be up to the extra weight. So he went conservative with the tires, choosing 265/70R17 All-Terrain T/As that measured 31.8 inches tall. The tires were mounted on American Racing ATX wheels.
CaRR was also conservative when it came to modifying the Honda Ridgeline's 3.5L V-6. "We didn't attack the full potential of this engine due to the number of stock components on board," explained Skilton. "We were worried that with an untested car, we'd just break it quicker. But it will be piped up."
"Piped up" meant improving how the engine breathes. Advance Flow Engineering fabricated a custom intake system that featured a massive, seven-layer air filter and a straight shot of tubing into the intake plenum. Skilton figured that modification alone was worth 15 to 20 hp. At the other side of the engine, Honda contributed a custom-fabbed, free-flowing header that lead to a straight-through exhaust system.
Aftermarket computer tuner Hondata thoroughly reworked the stock engine and driveline computers. All the OBD II "check engine" codes were removed, as was anything having to do with the emissions equipment that had been taken off. The shift points for the automatic transmission were modified so that it wouldn't upshift until the engine hit its 6,300rpm redline. We were surprised to learn that Skilton planned to keep the truck's column shifter. "I don't want to manually shift it," he said before the race. "I want to put it in Drive, lock it in Third and go. Third at 6,500 rpm should see between 100 and 105 mph. You don't want to go much faster than that in a stock vehicle."
One computer-controlled function that didn't change was the truck's complex VTM-4 four-wheel-drive system. "You've got four wheelspeed sensors and a speed sensor at the transmission, all talking to each other and balancing the torque between the front and rear wheels," said Skilton. "Since all the components are talking to each other, we're afraid if you remove one, you'll have trouble with the others." So while he would have liked direct control of the fore-aft torque split, Skilton opted to let the Honda's system do the work for him.
To hold the driver and co-driver securely within Temper Mental's chromoly cage, Skilton used Beard racing seats and five-point Crow Enterprises harnesses. A Fire Bottle on-board fire suppression system was installed in case of emergency, while for emergencies of a more mechanical nature, Skilton equipped the Ridgeline with a PowerTank CO2 tank and an assortment of air tools.
Though the CaRR team re-installed the stock instrument panel, it was augmented with auxiliary Auto Meter gauges (where the HVAC controls used to be) to monitor voltage, oil pressure, and transmission temperature. A drag-race-style Pro Comp Ultra Lite tach was hooked to the driver-side A-pillar. To help Skilton and his crew keep track of the course, they installed a Lowrance GPS system in the center of the dash. The GPS would help keep them out of trouble in another way, too: Race rules enforce a 60mph speed limit on highway stretches of the race course, and the data logger in the Lowrance system would monitor their ground speed.
Since so much of the 1000 is run at night-if you're in a stock truck, anyway-throwing a lot of light on the Mexican desert is crucial. Skilton's light source of choice was a Baja Designs Sol teK multiple HID light system and a roof-mounted bar that contained two spotlights and three floods. Powering the HIDs-as well as the rest of the truck's electrical systems-were two Optima batteries that had been relocated under the bed floor for better weight distribution.
The CaRR Honda Ridgeline made its debut a few weeks prior to the 1000 by going on display at the SEMA Show in Las Vegas. Once the show ended, Clive and Gavin Skilton, La Fortune, and fabricator Jason Rivera took the truck into the desert near Barstow, California, for a shake-down run. There, we had a chance to ride in the shotgun seat and sample what the team would experience down in Baja.
The first thing we noticed was the Honda's engine sound-not a V-8's throaty rumble, but something sharper. The truck moved out quickly, and since it'll reach 65 mph in First gear, there wasn't a lot of shifting for Clive Skilton to do in the rough terrain where our ride started.
The King suspension worked perfectly. The Ridgeline isn't a Trophy Truck by any means, but it soaks up bumps and whoops without a trace of harsh jarring. When Skilton did get the chance to open it up on a straight stretch of wash, the truck tracked straight and true. He and Gavin were both pleased with the result, though they did wind up stiffening the springs and firming the shock valving prior to race day.
Both Skiltons and La Fortune traded driving stints during the race. When we talked with Gavin afterwards, he couldn't say enough good things about the Honda Ridgeline's VTM-4 system. "I was skeptical, frankly, but it was unbelievable. What a pleasure to drive. At one point, after Jason climbed over the Summit, he dropped into a silt bed. But he powered right through, past something like six race cars and 20 chase trucks. When we got into the Matomi Wash, there are parts of it that are as technical as the Rubicon Trail. But the truck never spun a tire, never dug a hole in the sand. It was fantastic."
Skilton was also very happy with the driveline responsiveness Hondata programmed into the engine and trans. "When I came out of a corner hard, the transmission didn't downshift, so when I came back on the throttle, I was right back into the meat of the torque curve." He admitted that it took him a few miles to get used to the truck's front-wheel-drive-based driveline, as he's used to driving rear-wheel-drive-oriented Jeeps. "This truck isn't like rear-wheel-drive, where you can slide it through corners. It's more like a street motorcycle; it carves through the turns. You just point it where you want to go and stay on the gas. It's a different, more confident feeling. You never feel like you're chasing the car."
So, was Honda able to prove its truck had the guts to beat the Baja? Well, yes and no. The Ridgeline held up just fine. "Every stock component that started the race performed flawlessly," Skilton said, except for a rear driveshaft that fell victim to a locally made booby trap that caught the truck early in the race. Even so, Clive was able to drive it to the next pit for repairs, some 35 miles from the trap, running on front-wheel-drive alone.
Yet, despite the fact that it was still running strong, the truck didn't make it to the checkered flag within the time SCORE allotted to finish the race. Why? A combination of limited suspension travel and tires intended more for recreational use than Baja punishment. Skilton said they suffered seven flat tires in 350 miles. "Pinch flats," he explained. "When you're running out of travel and you're using a C-load-rated street tire on a 17-inch rim, the tire gets pinched between the rocks and the rim."
And every one of those flats was on the right front corner. "You never get a flat on the driver side," Skilton said, and we could hear the sheepish grin coming through the phone. "This truck is really wide; we could never get our minds around how wide it was. So we'd get in a situation where we thought we missed that rock on the right, but ...." Then again, Skilton said, "I'd rather take a flat tire than a crushed oil pan or a ruined transmission. You take 18 wheels and tires to a race, but only one engine."
Both Skiltons take full responsibility for the mistaken tire choice, saying they should have figured out a way to mount BFG's Mud-Terrain tires, which carry a D load rating (3,195 pounds) that's 25 percent stronger than the C rating (2,740) on the All-Terrains. "It was a bad choice of tires on our part," Clive said. "We knew it was a street tire, not a race tire." Added Gavin, "We know now that the truck will pull a big tire, but we didn't originally think it would."
Not ones to give up easily, the CaRR team took the Ridgeline back to the shop and made some changes. Using a hammer and torch, Skilton pounded on the wheelwells so they'd accept the 33-inch MTs. He also tweaked the suspension again-taking out the bumpstops and lengthening the limiting straps to give it more travel, and stiffening the spring rate one more time, to 500 pounds. "That will slow everything down, so we can keep the rocks away from the rims."
Just a week after the 1000 they were back in the desert: Nevada this time, for the Best in the Desert Henderson 400 and a happy ending to this story. Not only did the Ridgeline finish the race, 46th out of 137 starters, it won its class. The Skiltons say Honda was ecstatic about the truck's performance in both races, and the factory will continue the race program into 2006. After all, there is still the Baja to be tamed-on four wheels.