Supercharging plus nitrous oxide equals 300 hp
MORE THAN A
BLOWHARD BAGGER
34 • Motorcycle Bagger • October 2013 • Vol. 4, No. 7
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TOM JOHNSON DEREK CHURCHWELL BY
PHOTOS BY
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Vol. 4, No. 7 • October 2013 • Motorcycle Bagger •
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Turbocharger. SUPERCHARGER . BLOWER! NO MATTER THE TERM, FEW THINGS conjure up images of tire-frying power and insane dyno numbers better than forced induction, a handy, catchall phrase that describes exhaust-powered turbochargers and mechanically driven superchargers. Placed on the right engine and set up correctly, both forced induction systems generally can deliver more power — cubic inch for cubic inch — than any conventional modification, be it using radical cams and valves or increased compression ratio. And that leads us to Scott Smalley, the owner-operator of UPI Performance in Ashland, Ohio. As a bike builder, Scott likes horsepower in the sense that fish like water: he can’t do without it, and in fact prefers lots of it at a time. That’s where supercharging enters the picture, along with another favorite trick that’s favored by no-holds-barred hot rodders. I’m talking, of course, about nitrous oxide. Apparently believing that good things come in threes, Scott, with the help of his friends at Star Racing in Americus, Georgia, decided to build a 300 hp Road King to complement the pair of 200 hp Harleys he already owns. And, yes,
fellow skeptics, I’ve indeed seen the dyno charts for those bikes. The supercharger Scott chose for his 2004 King is a Procharger from Procharger Racing. The Procharger unit is unusual among superchargers in that it utilizes a centrifugal impeller, similar to what’s found on turbochargers, rather than the more common rotating lobes or screws. The Procharger even looks like a turbocharger, but with one defining exception: a mechanical drive that links the blower to the engine via belt and pulleys. As intriguing as it would be to watch them spinning wildly uncovered, moving parts sometimes develop an appetite for human flesh. With that in mind, Procharger wisely tucks theirs away inside a beautifully machined aluminum case that also houses the primary drive. Now for the question: how much power is a typical Procharger worth? One can easily add 50 percent to the output of an engine, which shakes out to 100110 hp from an otherwise stock Twin Cam. Those numbers are good enough for most Harley owners seeking an impressive bolt-on gain, especially considering that the power in supercharged engines
TECH SHEET Owner: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Scott Smalley, Ashland, OH Builder: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .UPI Performance/Star Racing Year/model: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2004 Road King Cost to build: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$65,000 Time to build: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Nine months Powdercoater: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Star Racing Painter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Holdfast Tattoo, Ashland, OH Color: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Black and silver
Oil pump: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle Cam cover: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle Primary cover: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Procharger Transmission: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BAKER Drivetrain OD6R Case: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BAKER Drivetrain Gears: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BAKER Drivetrain Clutch: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Barnett Scorpion, nonlock-up. Primary drive: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock chain Final drive: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51/23 530 chain conversion
ENGINE/TRANSMISSION
Engine: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle T124 Builder: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Star Racing Displacement: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124" Horsepower: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .310 Cases: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle TCSA Flywheels: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle 4-5/8" Balancing: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Star Racing, 52 percent Connecting rods: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle Cylinders: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle, 4-1/8" Pistons: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Star Racing, 10.5:1 Heads: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle B2, ported by Star Racing Cam: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle, .640"-lift Valves: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Star Racing Rockers: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle roller Lifters: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle Pushrods: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S&S Cycle Supercharger: . . . . . . . .Procharger, N2O system by Star Racing, Horsepower Inc. Fuel system: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62mm throttle body Air cleaner: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Procharger Exhaust: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Star Racing Pro Street Series Ignition: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock w/SERT
36 • Motorcycle Bagger • October 2013 • Vol. 4, No. 7
CHASSIS
Frame: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2004 Harley-Davidson Front forks: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Swingarm: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Front wheel: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RC Components Savage 3.50-21" Rear wheel: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RC Components Savage 4.50-18" Front brake: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Front tire: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Metzler ME880 120/70-21" Rear tire: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Metzler ME880 160/60VR/76V Front fender: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Rear fender: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock
AC C E S S O R I E S
Headlight: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Taillight: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Fuel tank: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Handlebars: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Seat: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C&C, Paramount, CA Speedo: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Auto-Meter Hand controls: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock Foot controls: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stock MotorcycleBagger.com
is “always on,” as Scott puts it. But for Scott and others like him, 110 hp is typically associated with cutesy economy cars with irrelevant names, not high-powered motorcycles. At UPI, where horsepower is the specialty of the house, Scott and crew decided to crank the numbers up by starting with an engine capable of 170-plus horsepower in normally aspirated form, no blower or nitrous in sight. That’s where Star Racing entered the picture. Proprietor George Bryce’s crew added a pair of S&S’ famed B2 heads (modified by Star) to a Star-assembled S&S T124 lower end. The B2 heads eliminated any possibility
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of a bottleneck between the engine and the Procharger Scott knew was coming, and was largely responsible for the 170 hp baseline. Excessive heat and its more ill-tempered partner, detonation, are the most common stumbling blocks in blower projects. Procharger addressed the potential problems in advance with an intercooler. Much more common in turbochargers than superchargers — before Procharger came along, that is — intercoolers allow airflow to cool the pressurized air moving from the blower to the engine. That cools the air/fuel
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mixture, making it denser, which means more power and, yep, increased cooling to ward off detonation and other heatrelated problems. Noteworthy here is that the potential for those same problems limits two important power enhancements — increases in static compression ratio and boost, or pressure, from the blower. Thanks to the intercooler and careful tuning with the Screamin’ Eagle Race Tuner, Scott’s T124 is fat-cat happy with 10.5:1 and, at final tally, a whopping 17 psi of boost. With the Procharger and intercooler installed (although the Procharger produced less boost at the time),
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the 124 cranked out 220 hp. Not bad, but nowhere near Scott’s goal. Even though his blown 124 was doing extremely well with standard-issue pulleys, Scott needed more power, so Procharger sent different pulleys. The jump to 17 psi increased horsepower to 258 — a big number, but still 40 and change short of the target. That’s when Scott whipped out his ace in the hole: nitrous oxide (I promise to spare you the stupid “giggle gas” cliché). Nitrous not only serves as an oxidizer that increases the amount of fuel that an internal combustion engine can consume, it also cools and densifies the air/fuel mixture, making N2O a big winner in the right hands. Amazing power gains are possible with it, more than enough to fold or fracture connecting rods, so the biggest challenge — besides tuning — is knowing when to stop. A 60 hp hit is reasonably moderate for most performancebuilt V-twins and would put Scott’s Road King safely on the high side of 300, so 60 it was. When he wants more (and you know that day will come), all he’ll have to do to the engine is change two jets and, depending on how far he goes, adjust the tune. The only change made to the baseline map for the blower and nitrous, by the way, was to retard the ignition timing a little, which provided a second benefit in addition to reducing the risk of detonation. Retarding the ignition helped increase power, with the best pull on UPI’s Dynojet being 310.25 hp with 240.41 ft-lbs. using a SAE correction factor. (Different correction factors change the numbers by a few percent. SAE numbers fall in the middle, between STD and raw, uncorrected numbers.) Scott notes that the stock brakes have been “adequate,” leaving other brute-performance fans to wonder about his Road King’s — make that Road Emperor’s — transmission and clutch. Scott chose a BAKER OD6 with R ratios and an 0.86 overdrive sixth gear. What’s the deal on R ratios, you ask? A taller than normal 2.82:1 first gear and 2.08:1 second let the bike stay in first gear longer to delay the ever-important first to second shift during serious launches and keep the wound-up engine at peak power through the shift by narrowing the gap between those two initial gears. Then again, with a supercharged 124 huffing nitrous, one has to wonder how important a narrow gap actually is. The powerband is fairly broad — say, from the time Scott pushes the starter button until he hits the rev limiter — but when you get down to it, banging hard first to second shifts with a close-ratio transmission is just plain fun. The clutch, which takes every bit as much of a beating as the BAKER, is a Barnett Scorpion with carbon-fiber plates, and — get this — it’s the standard coil spring, nonlockup version! Amazing product, two of which reside in my garage. Moving on, the bike’s sheet metal remains stock, although it’s spectacularly repainted by Holdfast Tattoo in Ashland. Yep, Holdfast tattoos motorcycle parts as well as skin. And in case you’re thinking Scott’s blower bike is a strung-out trailer queen/dyno king cross-dresser, think again. Blown but minus the nitrous, it has made Ohio-Sturgis roundtrips twice, averaging better than 3,000 miles with no problem each time, despite the occasional tank of 87-octane gas-as-swill that’s sometimes sold as premium motor vehicle fuel in parts of the country. And, by the way, although the engine’s horsepower fell to a mere 299.41 thanks to Florida’s heavy air, the bike won the Unlimited V-Twin class at Wyotech’s 2013 Bike Week Shootout. Big surprise, right? MB Vol. 4, No. 7 • October 2013 • Motorcycle Bagger •
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