Fuel 101

FUEL 101

RACE WATCH

HILLCLIMB

UP, UP AND OVER!

Kevin Cameron

TO LEARN ABOUT hillclimbing, I phoned Dan Watson, veteran builder of nitroburning `climbers and father of seven-time national champion Dave Watson. Unlike most other motorsports, hillclimb continues to embrace the three classic racing fuels: gasoline, alcohol and nitromethane.

I asked Watson about the differences. "It’s evolved over the years," he said. "Out west-California, Idaho-they have those steep mountains. Their hills have turns in ’em." Watson explained that western hilldimbers are therefore closer to motocross and run on gas, with carburetors, emphasizing control rather than sheer power. "A nitro-burner out here on the East Coast will be a lot longer. Our hills are primarily drag strips with bumps in them.”

When you see a successful nitro run, the bike goes straight, its rear tire throwing a long jet of dirt. The rider has to leave straight, then stay straight on landing after the "bumps,” keeping the rear tire in contact whenever possible. Airtime is wasted time. A poor landing sends a bike veering off course.

Nitro burners today are mainly four-cylinder sportbike engines. “There’s a couple of Triumphs,” said Watson. “Maybe a Flarley.”

Nearly all run Hilborn continuous-flow fuel injection. “Nothing much else in the last 20 years,” said Watson. The Xtreme class is up to 750cc and Unlimited carries on from there, making an estimated 300 horsepower.

Why Hilborn? Nitroburners need massive fuel volume. "You can make carbs work,” said Watson. "Earl Bowlby did years ago, but it’s so much easier with the Hilborn.”

And alcohol? "There’s just not enough horsepower with alcohol.”