Does size matter? How much? That was the question many of America's top streetbike drag racers were asking themselves at the end of last season when AMA/Prostar announced new rules for its premier streetbike-based drag racing class, Pro Street. In an attempt to break the Hayabusa juggernaut and to increase the diversity of motorcycles racing in the class, AMA/Prostar rewrote the rules to give substantial weight breaks and other advantages to 1000cc-based motorcycles to make them competitive against the larger-displacement Hayabusas and other big-bore race bikes. Built right, would a lighter liter bike be able to get to the other end of the quarter-mile quicker than a more powerful, but much heavier, unlimited-class bike?
It looks like we will soon find out. One of the nation's top Pro Street racers, two-time national champion and (at press time) Pro Street e.t. and top-speed record holder Kent Stotz, is getting ready to retire his Honda CBR1100XX Blackbird racer and trade it in for an all-new Honda CBR1000RR-based race bike--the first liter-based Pro Street racer built by a major competitor. How it will turn out is anyone's guess. Unlike the world of NASCAR, where changing models basically means swapping out the faux headlight stickers, the CBR1000RR and the CBR1100XX are utterly unlike one another and represent completely different challenges to getting down the drag strip in under eight seconds and over 200 mph.
"The new 1000RR is a totally different bike from my trusty 1100XX," says Stotz, describing the process of starting over with a bike that's smaller, lighter, and carrying 200cc less displacement than his big Blackbird. And "starting over" is the right term for what he's doing here: Stotz has been racing and developing his Blackbird for six years now and has built it into one of the fastest (see the aforementioned class records) and most consistent race bikes on the strip. Walking away from such a successful machine at a point when it is still so dominant is the right choice for the class, for his sponsors and for him as a tuner, Stotz says.
Stotz's primary sponsor is Honda Motor Company (via the Honda Rider's Club of America), and they've been gently urging him for a few seasons to shift his racing program over to a model that makes more marketing sense for Big Red, as the company no longer sells the CBR1100XX model in the United States, and even when it did, the bike hadn't been a very big seller. "Now that I'm racing a bike with much larger overall sales," Stotz says, "the benefits to my sponsors--both Honda and the aftermarket companies helping me develop performance products--are a greater for everyone."
Stotz is also looking forward to the challenge of developing a new model. "It's hard to let go of a bike with so much development invested in it and that has brought me so much success, but I love to test new ideas," Stotz says. "I look forward to this new challenge. There have been times when I could have left well enough alone, but that's not the way to keep advancing over the long run." And no one has been more responsible for advancing streetbike drag racing--politically, promotionally and technologically--than Kent Stotz.
Light Makes Right
The main advantage to running a 1000cc-based motorcycle in Pro Street is the weight break--there is no minimum weight for liter bikes in that class, while big-bore bikes must weigh at least 685 pounds (combined bike/rider weight)--so Stotz's overriding goal when building up this new bike was to shave as many pounds, ounces and grams as possible. This is somewhat ironic because for a long time the goal was to add more weight to drag bikes to improve the ability to launch and get down the strip. As recently as the second round of this season in Atlanta, Stotz was disqualified for having an "illegal" front wheel that contained components remanufactured to be even heavier than before.
With this new bike, Stotz is going to extreme lengths to make it as light as possible to maximize its power-to-weight ratio and not give up too much of an outright acceleration advantage to bigger-displacement, higher-horsepower bikes. "I have typically had one of the heavier bikes in the class for the last 10 years," says Stotz. "Before the release of the Mickey Thompson MCR2 ["Not recommended for street use unless racing for more than $500," the Schnitz Racing web site used to note], a tire needed some weight on it [to get the best traction]." But now, with the stunning advances in tire technology, a bike can be a featherweight and still hook up off the line. Stotz expects to take advantage of this development by building this new bike into an ultralight ride.
Toward this end, Airtech made special lightweight bodywork for the bike, and BST supplied state-of-the-art, carbon-fiber wheels. Even Stotz's choice of shifter--the Pingel Super Shifter instead of the heavier Pingel Premium Shifter that he used on the Blackbird--was influenced by the scale. Stotz is so serious about saving grams that he's even scrutinized the gear that he wears on his body and has technicians from Joe Rocket redesigning his race suit with lighter materials. "Even my new sponsor Scorpion Exo Helmets has one of the lightest helmets on the market," said Stotz, who's leaving no stone unturned in the quest to shed pounds and ounces.
With less rotating weight and less overall bike weight to push down the track, Stotz is hoping that the horsepower difference of the smaller bike won't prove to be a disadvantage. He estimates that the CBR1000RR will ultimately produce 450 horsepower and weigh just 400 pounds--585 with Stotz on it--enough to produce competitive e.t.s in the 7.20 range.
Heavy Breather
Cutting all that weight is one thing--the other part of the class-winning equation, of course, is boosting the CBR1000RR's power output from a stock 155 hp to the (admittedly outrageous-sounding) target of 450 hp. Like his Blackbird (and every other bike in the Pro Street class), Stotz will employ a massive turbo to get him there. "Velocity Racing has built a turbo system for the RR using the same Velocity-tweaked, Garrett GT35R that we used on the XX," Stotz says. "The Blackbird had an 1192cc motor. But now with only 998cc on the RR, it will be a challenge to get this small motor to spool up the big turbo and not fall off in power leaving the line."
To make it all work, Stotz will lean heavily on his tuning colleagues Barry Henson of Velocity Racing, Steve Nichols of Dyno Dynamics and Stephano Perota of Magneti-Marelli, who have all helped him achieve so much success last season. Stotz is especially enthusiastic about the ECU (electronic control unit) from Magneti-Marelli. Controlling boost, fuel and electronics on Pro Street bikes before the advent of the latest Magneti-Marelli ECU required as many as six individual control boxes and five separate gauges. The new system replaces all those with one box and one electronic dash unit. All data logging, boost control, shift kill and other vital functions are contained in the ECU. "It's the highest level of motorsports electronics available, but it's at the very beginning of the product development cycle for Pro Street," Nichols says, describing the system.
Stotz says that the existence of this technology is essential for him to even contemplate a 400-plus horsepower liter bike. "This was not possible just a few years ago. Back then I would not have even tried the same turbo that I used on a 1200cc motor on a short-stroke, 1000cc engine. But even with the combination of the small motor and big turbo, the Magneti-Marelli ECU's tuning capabilities keep the cylinders firing so cleanly that it's not a problem to keep the turbo spooled."
The combustion charge is delivered to the chamber through a Star Racing ported head and ignited atop JE Pistons that push down on Falicon rods. "My long-standing sponsors have worked together on this project to get me the most reliable power right from the start," Stotz says. "Also, Honda engineering is second to none, and the new RR is no exception. It was not designed to endure 400-plus hp, but the company's stock components, with the Honda Pro Oils protecting them, have proven more than reliable to date."
One RR component that Stotz is especially excited about is the cassette-style transmission. "I wish we would've had that on the XX at the `05 World Finals!" Stotz says. "We missed the photos in the winner circle there because tech tore us down to check for an auto transmission (which we didn't have). On the XX, it took two-and-a-half hours to pull the motor and split the cases to get to the transmission. We can pull this transmission [on the CBR] out in just fifteen minutes." Robinson Industries constructed special billet transmission gears with thicker dogs for Stotz to insure that the transmission can withstand the estimated 450 hp the bike will make. Just because you can repair the transmission easily doesn't mean that you necessarily want to.
Putting It All Together
Stotz has years of chassis development experience behind him, and he used every ounce of it setting up the CBR1000RR. Remember, the factory designed this bike expressly for getting around corners and not going in a straight line. "The chassis on the two bikes are very different from each other," Stotz notes. "It will be interesting to see what this one wants in the way of fine-tuning to get all of the bike components to work in unison." Squatter and smaller than the bulbous Blackbird, the aggressive-looking RR carries all of its bulk near the front--which is where you want it on a drag bike. The RR's stock wheelbase is three inches shorter than a stock Blackbird, so Stotz was able to put an even longer, higher-leverage swingarm on the RR and still stay within the 68-inch class limit for turbo bikes. To make the bike squat just right at launch, Hyperpro built a new shock calculated to cooperate with the RR's unique suspension geometry and lighter weight. The final component to get this power to the pavement is the sticky Mickey MCR2 tire, which is mounted on a BST carbon-fiber wheel in the rear.
One final trick that Stotz adapted from the Blackbird is turning the fork legs around 180 degrees so that the brake calipers are in front of the forks, rather than trailing behind in yet another attempt to get every last ounce of weight as far forward as possible. "That cat's out of the bag on that," says Stotz, laughing. "I ran my forks that way for two years on the Blackbird, but no one ever noticed it because the front fender covered it."
All that's left now is the testing--and Stotz will be testing extensively this summer at his local tracks with help from his sponsor Schaumburg Honda in preparation for the bike's scheduled debut at the Indianapolis round of the AMA/Prostar series this coming August. "The RR's a really cool piece, but everything's unknown," Stotz says. "Can it beat the Blackbird? I think so, but how long that will take, I don't know." Once the RR is up and running, Stotz says the Blackbird will go up for sale. "But the price for it just went up!" Stotz says with a laugh, recalling his string of 200-plus mph runs at the season opener in Valdosta, Georgia. "Because the Blackbird's not just a fast bike, it's consistently fast--and that's hard to find!"
If Stotz plays his cards right, he'll be able to make the same claim about his new CBR1000RR at the end of the 2006 season. From where we're sitting, it looks to us like he's off to a good start.