Yamaha listened, they designed and then they tested. The new Genesis 998 Turbo engine is a product of their dedication to bringing the most advanced, high performance engines to the snowmobile industry. With more horsepower than any production engine in the history of our performance-obsessed sport, they are confident when they say the Sidewinder has the “Power to Satisfy”. Combine that with Yamaha’s fanatical dedication to durability and reliability, and they are doubly confident when they also tell you the Sidewinder will deliver “Round-Trip Reliability”.
Everything about the Sidewinder’s Genesis 998 Turbo engine is pure Yamaha engineering – from the intake, to the large-finned intercooler to the spec of the high-tech IHI ceramic bearing turbo unit to the high-tech engine management system to the exhaust. Yamaha’s master engineers designed and engineered this engine from a blank sheet to give you the performance you would expect from a Yamaha turbo sled. The side-mounted turbo unit allows short pressure tubes for razor-sharp response. The exclusive triple throttle bodies are a first in production turbo engines, regardless of industry. Not even the exotic car manufacturers go to this length to deliver crisp, right-now performance!
Yamaha has staked their reputation on quality, durability and reliability – more commonly referred to as “Yamaha Quality”. The Genesis 998 Turbo engine package carries a full suite of features to ensure you have a great day on the snow and a fun night when you reach your destination. Yamaha uses their advanced nine-sensor engine management system to control fuel flow for maximum performance, but it also incorporates a knock sensor to sense detonation and adjust ignition timing and even manifold pressure if the need should arise, eliminating worry about fuel quality issues. The Genesis turbo was designed to operate on premium pump fuel, but will adjust these parameters if high output is demanded by the operator when using regular fuel.
Yamaha developed the crank and rods to handle the amazingly high torque load of the 998 Turbo. A specialized press method manufacturing process is adopted (forging process without twisting of the metal) to provide the needed strength to the crankshaft assembly to withstand the additional stress produced within a ‘boosted’ engine. The engine’s big end connecting rod bushings are individually ‘size selected’ to exactly match the crankshaft journals to the connecting rods for a uniform, high tolerance fit.
Yamaha has well over a decade of experience in harnessing the unique power delivery of a high performance four stroke engine in a snowmobile. For the hyper performance Sidewinder, they also developed a new YSRC roller secondary system to deliver aggressive upshifting while also backshifting quickly to keep you in the power. In addition, they slightly upsized the new secondary to overshift and let the Sidewinder stretch its legs on a long lake run.
High Tech Turbo
The Nickel alloy turbine body on the Genesis 998 Turbo is extremely strong and precise, able to withstand highly elevated temperatures. Supported by premium, ceramic ball bearings, the Inconel turbine blade assembly is very light and strong. This yields a low moment of inertia for lightening quick response to exhaust gas input. The aluminum die cast compressor body houses a lightweight aluminum impeller for instant response.
Special, light weight, hardened carburized steel connecting rod design has the optimum strength required to produce maximum power. This new turbo-specific rod design uses nutted studs to join the close-tolerance, machined-faced big end. The rods are also treated with a special Defric coating for cold start protection, to ensure long life and maximum reliability.
The Yamaha-developed Mitsubishi ECU on the Genesis 998 Turbo uses a series of 9 sensors to gather running condition data and computes using its predetermined memory ‘map’. It then adjusts ignition timing, fuel delivery, manifold air-pressure and turbo boost pressure to produce maximum performance – reliably. The system targets absolute pressure in the intake manifold, using pressure sensors on both sides of the throttle bodies. When the throttle is closed it re-routes pressure to the front of the compressor so you don’t have to wait for the exhaust pressure to rise when the throttle is reapplied, via an air bypass valve.
The forged aluminum pistons are formed without melting the original aluminum stock, so they retain the strength of the original solidification structure, which enables the design of a lighter piston. The forging process also allows Yamaha to control material thickness to reduce weight by eliminating unnecessary material while still maintaining high strength. A form optimized scraper ring provides maximum protection against oil consumption and blow-by.
The Genesis 998 Turbo engine features a unique piston cooling system. Oil is sprayed directly at the underside of the pistons through special jets to help cool and lubricate them. Cooling the pistons helps ensure maximum reliability from this premium, ultimate performance Yamaha engine. A convection system also keeps engine coolant flowing after engine shut down to cool down critical components.
Triple Throttle Bodies
Yamaha engineers wanted to develop a turbo so smooth and so quick to respond that it doesn’t feel like a conventional turbo. One of the ways they achieved their goal was to develop the intake system using three separate 41mm throttle bodies instead of just one— something that is not seen in any other production turbo on the planet. And another first for Yamaha with the Genesis turbo. This provides instant throttle response before turbo boost, all but eliminating the transition.
For the Genesis 998 Turbo Yamaha engineers designed a unique cast steel 3 into 1 manifold to precisely match the chassis and turbo mounting layout to help create the shortest path possible to the turbine. This compact component is connected to the turbine by a short, vibration-isolating tube. This results in exhaust energy being transferred very efficiently to the turbine for instant response to the slightest throttle input.
With power of 190-200 HP and instantaneous throttle response you will not know this is a turbo as there is ZERO turbo lag, no strange noises and nothing but instant over-the-top power at ALL elevations. This is a purpose-built engine package that will forever change your impression of what a 4-stroke snowmobile is capable of.
Yamaha engineers wanted to develop a turbo so smooth and so quick to respond that it doesn’t ‘feel’ like a conventional turbo. The transition between being a normally-aspirated engine and a turbocharged engine is incredibly smooth and seamless, and instant. It is virtually impossible to detect this is a turbocharged engine, except for the fact it produces almost 200 horsepower. Peak power occurs at 8750 rpm, with peak torque at 6500 rpm – providing over 2000 rpm of torque backup.
Actual performance compared to the SR Viper 1049 triple shows significant gains with 50% more torque across the full operating RPM range along with a 40% increase in horsepower. There is also a big power lift in comparison, between 3500 RPM and 4500 RPM where the clutch system begins its shift-out phase. This translates into more rapid acceleration at low RPM, a direct result of achieving the engineering targets for maximum response using a turbocharger. Suffice it to say, this is a complete and total performance package, engineered from the ground up to be a turbocharged engine that will not only impress but satisfy, for year after year. In typical Yamaha fashion, no less.