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Pro Stock V-Rod progressing?
With Harley -Davidson money and the Vance & Hines drag racing track record, the billet-hewn NHRA Pro Stock V-Rod drag-bike wasn’t expected to have this much trouble qualifying in its first season. Even after running its quickest time yet-a 7.457-second/176-mph run at the Indy nationals this past summer-it still missed the qualifying cut by a little less than a tenth of a second.
To find out firsthand what some of the challenges have been, we spent a few minutes speaking with engine designer Byron Hines in a telephone call to the V&H race shop in Colorado.
“It’s starting to show some promise now,” says Hines of the clean-sheet design, “but we were way too conservative at the beginning, in porting and timing and so on. It looked good on the flow bench and it’s been a great dyno engine, but on the track it was a brick.”
He went on to note that an originaldesign engine like this has all its firsttime variables to nail down-variables that are already known for productionbased engines-things like valvetrain issues, pushrod deflection and valve-spring seat pressure.
“Reliability issues-rod bearings, clutch, primary gears, cylinder sealing-those have all been good. The bike is 60 pounds overweight right now, and there’s a new frame coming. It’ll qualify if we just put it on the weight minimum.”
Differences between the controlled environment of the dyno and the realities of the track have held up progress.
“On the bench, the cambelts don’t even move,” noted Hines. “On the track, running rough, we’ve broken parts. The biggest problem has been the ignition.”
After episodes of detonation dishing the front piston, the team discovered that its original ignition could get confused between cylinders and suddenly jump an extra 60 degrees (the cylinder Vee angle), adding this to the normal timing, firing that cylinder at 85 BTDC! They are now running two separate ignitions, one for each cylinder.
According to Hines, the top Suzuki Fours make 320-325 horsepower on a Superflow 901 dyno, and have good power from 11,000 to 13,600 rpm. He says this wide power is necessary to sustain fifth-gear acceleration across the second eighth-mile. Peak power may make the dyno crew feel good, but low E.T.s come only from a high average horsepower over the range that the engine must pull across.
“We’re 10 bhp shy of what it needs in that band,” he says. “There’s good power at 7800-8000, but then we lose 20-25 bhp at 8500.”
This refers back to his first statement-about being too conservative at the beginning. With a giant 2600cc engine like this one, piston speed is tremendous, and it would have been daring indeed to design for peak power at 8500 rpm. Yet this season’s experience proves this engine has the necessary strength. During overrevs from gear breakages the engine has run on to 9800 rpm-yet rods have held together and the rod studs did not stretch. This is a piston speed of more than 7000 feet per minute-40 percent higher than what’s usual in Formula One car racing. The gear breakages are a headache, but do suggest the engine is gaining power. Once porting and valve timing are adjusted to deliver the air the engine needs up high, the Towering Twin may yet live up to its expectations.
Combustion speed in the big 4.75inch-bore cylinders is not a problemthe most ignition timing the engine has needed is 26 degrees BTDC, with 2425 degrees at peak torque.
Packaging under the tank has been difficult, because the intake lengths the engine needs to run strong threaten to make the bike look like a Mississippi steamboat. There have been some crankcase “compression ratio” and ventilation issues-as there always are on VTwins, whose very big pistons move nearly together and displace a large volume of air.
Hines summed up the current state and future plans by saying this: “The others are two-and-a-half tenths ahead of us right now. We have to up that power average, get some weight off and make the bike easier to work on.” The classic issues of racing. -Kevin Cameron
Pichon, Everts set moto records
The World Motocross Championships finished up in Moscow, Russia, this past September, and what a year it was with records set by Belgian Stephan Everts and Frenchman Mickael Pichón.
Rinaldi Yamaha rider Everts collected his record-tying sixth championship with his 500cc title. In addition to equaling rival Belgian Joel Smets’ alltime championship tally, Everts also won the 54th Grand Prix of his career, putting him on top of the all-time win list. Although he obviously had a fantastic season, Everts didn’t have it all his way in the 500cc class. KTM factory rider Smets was right there the whole way through the series. Four of Smets’ six titles have come in the 500cc class, and his seven wins this season had him in contention for yet another. Unfortunately, engine failures at two GPs and a huge crash in another ruled him out and Everts finished the series with a comfortable margin. Third place overall was Spanish charger Javier Vico Garcia, also on a KTM.
Said Everts, “To win six World Motocross Championships, that is a dream I’ve had since I was a small boy. I put a lot of pressure on myself this year, wanting to take my 51st GP victory and have the all-time record. Once I got the record it was easier and I took more wins, although Smets was very strong. But that just motivates me even more for 2003.” Corona Suzuki rider Pichón, meanwhile, won his second-consecutive 250cc World Championship in dominating fashion. The 25-year-old went about winning races with the ease of Jeremy McGrath during his Supercross heyday. Pichón won nine races in a row, a season record in the series, and took the overall in 11 of 12 rounds, only losing the one after crashing in the first-turn at the German GP. Pichón was never troubled by his rivals, although New Zealand’s Josh Coppins pushed hard all season to finish in second place, while German Pit Beirer was third.
“I felt last year was tough when Chad Reed and Gordon Crockard both had good moments,” said former AMA racer Pichón. “But this year I was much stronger and nobody really gave me too much trouble.”
The 125cc series was, without a doubt, the most exciting of the three classes. From the moment the title chase began in Valkensvaard, Holland, several riders fought for the championship. Kawasaki’s Mickael Maschio finally took the crown, although only by 4 points from Steve Ramon and Patrick Caps, both Belgian KTM riders. Going into the last round in Russia, Maschio had a 10-point advantage, only to see Ramon win and nearly take the title.
“It has been a long season,” Maschio said. “So much has happened with several riders taking Grand Prix victories. In the end my KX125 really helped me, because we didn’t have any mechanical trouble all season long.” -Geoff Meyer
