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The Engine That Saved Arctic Cat

Arctic’s new 800 Twin C-TEC 2
2018 Arctic Cat XF 8000 Cross Country with 800 Twin C-TEC 2 engine
There are many like it, but this one is mine! The 8000 motor comes in many trims from Cat, but the Cross Country is an AmSnow favorite!
Now that the smoke has lifted following the Arctic Cat Textron merger, we can see the outcome with clearer vision. It is tempting to call Arctic’s new 800 Twin C-TEC 2 snowmobile engine the "program that saved Arctic Cat."

Why would we say that?

As we now know, Arctic Cat successfully merged with Textron Corporation in a combination that not only saved jobs in St. Cloud and Thief River Falls, but could even add employment at both locations. I feel the deciding factor in the merger was Arctic’s new engine plant in St. Cloud, which will see an expansion as Textron moves more engine production into the country from its German Division.

It all started with Arctic’s ambition to manufacture its own engines in a new plant located in St. Cloud, MN. Over the years Arctic Cat had used outside engines from various manufacturers like Hirth, ILO, Kohler, Sachs, Kawasaki and Suzuki. Buying engines from outside sources always means you have to abide by the suppliers resources and capabilities. As competition pressure increased from Yamaha, Polaris and Ski-Doo - who all manufactured their own engines - Cat concluded they needed more control over development, design and manufacturing to stay competitive in the rapidly changing snowmobile industry. Starting your own engine manufacturing plant requires a large investment in facilities and production equipment, and many questioned the wisdom of the move at its inception.

At first, just ATV engines were produced at the plant, while the Arctic engineers worked hard on designing the 600 and 800 power plants. Arctic wanted both a strong and reliable power plant, as well as a technically sophisticated design that could meet all the new emission requirements. When Arctic finally introduced the 600cc C-TEC 2 engine, it bristled with new features like the innovative dual stage EFI with slotted pistons. This design solved both the emission problems and crankcase cooling and lubrication problems related to lean running, emission compliant 2-strokes. By introducing the 600 engine first, Arctic secured time in the field with the new design before enlarging the engine to 800cc.
The 6 and the 8
The first time we saw the cylinders of the 600 engine, it was very obvious that there was plenty of wall thickness to allow much bigger pistons. The stroke on the 600 was 70mm with a 73.8mm bore. The 800 retains the same 70mm stroke, but has the bore increased to 85mm. Obviously the engine was originally designed as an 800, then the bore reduced to give 600cc. So, 600 owners actually got a very strong 800 crank designed to take up to 200 HP.

The early experience with the 600 C-TEC 2 was very promising. Warranty and repair claims were way down from experiences with outside-built engines. The engine was also very easy to assemble. Engineers commented that 4-stroke ATV engines required 18 to 20 assembly stations, while the 600 C-TEC 2 2-stroke only required 10 total assembly stations for a complete build. The Arctic assembly line is a very impressive state-of-the-art facility with a number of quality control stations in the assembly process, to ensure 100% compliance with quality goals.

The 800 C-TEC 2 engine follows the same architecture as the 600 C-TEC 2 engine (or vice-versa depending how you look at it). Arctic’s advanced layout locates the 50mm throttle bodies in front, breathing into the crankcase through Arctic’s W-designed four petal reeds, giving a total of 16 reed petals on each cage for maximum intake efficiency. No fuel is injected through the throttle bodies, only clean air enters the crankcases. The cylinders are tilted back, which not only gives a favorable center of gravity, but also provides a stiffer crankcase due to its taller top cross-section. The exhaust exits in front, but curves back and over itself before exiting the muffler on the right hand side.

Arctic’s fuel injection system is a cleverly patented design that addresses a number of emission problems. The single EFI injector is located in the back port spraying down on the hot piston at low RPM when unburned fuel would often escape out the exhaust port if all five transfer passages carried fuel. In this case, the four side-transfers carry clean air which catches the fuel and directs it up the back of the cylinder. This first stage only injects fuel while the back port is open, limiting the amount of fuel that can be injected at full load.

On a 2-cycle engine, unburned fuel escaping the exhaust port is only a problem until the tuned exhaust provides a return plugging pulse - typically from 4000 RPM and up - that keeps fuel in the cylinder. When the RPM and load increases more fuel is needed, but now it can be delivered through the side-transfers, since the tuned exhaust plugging pulse keeps the fuel in the cylinder. In order to get fuel into the crank case, Arctic cleverly machined a slot in the piston right in front of the injector. Stage II now kicks in with a longer injection period, spraying fuel through the slot in the piston and lubricating top and bottom bearings as well as cooling the crankcase before the fuel enters into the cylinder again through the side-transfer passages.
Arctic Cat 800 Twin C-TEC 2 engine
Arctic Cat 800 Twin C-TEC 2 engine
The laid-back cylinder design and patented fuel injection system are distinguishing features.
Smart motor, smart move
This system is simple, and economical to build, because it only requires one EFI injector per cylinder. Lubrication is provided by an electronic oil pump delivering oil into the fuel rail to mix with the gas, and also into the air intake flanges to meet load demands. The cast high silica pistons have two straight rings and special skirt coating to lower friction against the nikasil coated cylinder bores. The Suzuki 800 twin had twin spark plugs, but the new 800 uses a more efficient combustion chamber design with only one centrally located spark plug.

Power valves have also now evolved into very sophisticated systems controlled by a computer-steered servo motor. Arctic’s APV exhaust valve system controls both the main and side ports, with an electronic management system that receives input from engine RPM and pipe temperature as well as barometric pressure. The result is a more responsive and crisp engine performance - especially in low and midrange load levels. The new C-TEC 2 800 is more powerful than the 800 Suzuki it replaces, with far cleaner and crisper performance. You also get better fuel economy and improvements in durability, all while keeping a high standard of reliability.

Arctic’s gamble on its own engine manufacturing plant not only delivered a strong performing and competitive engine in the 160 HP class, but was possibly a deciding factor in the merger with Textron. The merger not only saved jobs but also could add capacity. In these uncertain times, it was a gamble that paid off with a more secure future for Arctic Cat.
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