Walking the aisles at the recent PRI show turned up this incredible gem of an engine, positioned front-and-center in the Precision Turbo booth next to a snowmobile, of all things. Engineered and built by Craig Campton and the team at Hypersports LLC in Arlington, Wisconsin, the engine displaces a whopping 70.1 cubic inches and makes a documented 604 horsepower, nearly as much power as your author’s supercharged eight-cylinder 302 ci engine, with approximately 3,200 pounds less to haul around.
Wondering how? So were we. A discussion with Campton helped us to understand just how he and his team squeezed so much power out of so few cubic inches; the displacement of 1.15 liters is only a bit more than half of your average bottle of Coke. And the journey starts in what would typically be a most unsuspecting place for a snowmobile engine builder — NHRA Pro Stock.
“I was with the Victor Cagnazzi team with Jeg Coughlin and Dave Connolly, and we won multiple world championships and many, many races,” says Campton. “I’m originally from Wisconsin and moved to North Carolina and did that deal, but it got to the point where Pro Stock is pretty intense; it’s difficult in my opinion to conduct a reasonable family life due to the travel.”
Campton left the Cagnazzi team, but continued to build Pro Stock engines in Wisconsin and lease them to racers like Jim Yates and Ryan Ondrejko while pursuing his passion of riding sleds in the cold Wisconsin winters.
“Where this all crosses is that my connections at Artic Cat contacted me when I was in Mooresville, and told me this engine was coming down the pipeline. I’ve been working on this engine platform for coming up on eight years now,” he says. “It is a four-cycle engine, and you pay attention to ring placement, and cylinder finish, piston design, everything that we’d use in a turbocharged Outlaw 10.5 build or a turbo Pro Mod on a professional level; all the same stuff still applies. We took this engine and took it to the next level.”
“This engine was manufactured by Suzuki for Artic Cat, and the unique thing about this engine is that it’s a two-cylinder, even-fire four-stroke and has four valves per cylinder — it’s very similar to the Hayabusa platform,” says Campton. “It looks like you took the center two cylinders out of a Hayabusa cylinder head, put it back together, then increased the size by 30 percent. The engine was originally designed back in 2006 as a naturally-aspirated engine; they knew which direction they were going, and it’s manufactured in such a way that the rod and main pin dimensions were very large and robust compared to a normal engine of this displacement.”
This robust platform lends itself to — you guessed it — forced induction. By adding a turbocharger to the mix in 2009, the Artic Cat engine makes 177 horsepower at 7,800 rpm. But the Hyperformance team has pumped up the performance of the engine to astronomical levels, especially when the factor of a 440-pound sled is taken into the equation.
They made a trip to Dynotech Research following the conclusion of one of their race events for testing the engine in its current configuration and twisted the dyno to 604 horsepower at 9,400 rpm with 50.5 psi of boost pressure. They’ve successfully run more boost than this, but haven’t been back to the dyno to quantify the results.
“If we sit and break down the times that these Outlaw snowmobiles run with north of 600 horsepower at 440 to 460 pounds without rider, we’re talking about a power to weight ratio that’s pretty incredible,” says Campton.
These sleds are raced on a 500-foot track that’s capable of holding the sled as it launches to sub-1.10-second 60-foot times on its way to 3.80s at 141 miles per hour. Or, on an eighth-mile track on the ice, the sled runs 4.40s at over 150 mph, equivalent to the top runners in the X275 drag racing class. Simply incredible.
“Considering that we’re doing this with a track and not with a tire; we’re fighting reciprocating and rotating weight as the track is trying to change direction, it’s reasonably impressive in my opinion,” says Campton.
So what sort of internals are required to make this type of power from only two cylinders? Campton was willing to share some — but not all — of the details with us.
Some of the relationships he formed in the automotive world have also been tapped to provide products that are proprietary to Hypersports; the collaborations are the foundation of what the company has been able to achieve with this impressive platform.
The OE blocks are cast from aluminum with a deck height of 199 mm and 105 mm bore spacing, with Nikasil-coated bores for wear resistance. A custom 3.000-inch stroke billet crankshaft swings custom Carrillo 5.067-inch-long connecting rods ’round. CP pistons fill the 3.858-inch bores, and set the compression at a boost-friendly 8.5:1 ratio.
Using the Hypersports CNC-ported cylinder head filled with 36 mm intake and 33 mm exhaust valves, a pair of custom Hypersports camshafts actuate the valvetrain. A Cometic gasket seals the head to the block when the monstrous boost pressure is looking for every avenue to escape. One might think that this engine requires a custom intake manifold, but Hypersports makes the factory piece work, albeit with heavy modifications.
One of Hypersports’ billet 56 mm throttle bodies sucks down the boost from the Precision Gen 2 Pro Mod 6062 turbocharger, and the 1600 cc injectors and engine management is handled by a Vi-PEC engine management system tuned by Glenn Hall at D&D. Out front, a Hypersports front mount intercooler chills the intake charge. The engine runs on VP Racing Fuels‘ Import dino-juice.
“We’re a one-stop shop — someone can come in here with a stock sled and whether we build a fabricated chassis or a modified Outlaw sled, they’ll leave here turnkey. I’ve been spoiled by the professional motorsports world, but this sled stuff is pretty insane,” sums up Campton.