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Is SHOT the cure?

New Ski-Doo starting system gives mountain riders relief.
RELATED TOPICS: SKI-DOO | MOUNTAIN SNOWMOBILE
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Never Be Blue Again! The mountain crew won't be crying about electric start and extra weight anymore with SHOT.
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The weight of the new SHOT starting system is such a savings (the entire system is 20 lbs. lighter) that mountain riders are jumping out of their seats about it.
Lightweight, easy to use, and simple. That’s what Ski-Doo realized that mountain most riders wanted. Of course, they were sick of constantly pulling a rope to start their sleds.

When Ski-Doo introduced the new 850 E-TEC engine last year for the 2017 season, it had a new electric starter system that aimed to give rocky mountain riders what they were asking for. This new starter resembled a conventional starter system that normally engages a ring-gear on the clutch, but it was smaller and geared down to reach
a smaller ring-gear now mounted on the new flywheel.

We thought it was a nice upgrade from the standard system. But that was before Ski-Doo engineers dropped their incredible new “SHOT” technology on the industry just one year later.

Ultra-capacitor, ultra-cool


The SHOT starting system completely replaces the electric starter, ring-gear and battery, a weight savings of more than 20 lbs. (The SHOT’s ultra-capacitor box weighs only 2 lbs.) The fully charged ultra-capacitor is discharged through a programmed ECM into the coil windings of the stator charging coils, reversing current flow and changing the stator system into a starter motor to spin the flywheel and start the engine.
Changing the charging system into
a starter motor has been tried before in the automotive world, but the result was always a system that was too large, too cumbersome and required larger batteries. As a result, smaller electric starter motors and ring-gears won out, and this technology has not been challenged for over 50 years. Until now.

Two technologies emerged to make the SHOT system possible. First, the E-TEC system evolved. E-TEC injection requires a larger energy delivery to run the injection magnets, so it needs a more advanced charging system. The 850 charging system delivers 1,360 watts through a larger flywheel and more charge coils, all designed into a very efficient three-phase system (you can read more about this in our Spring 2016 issue, p. 10). While designing the new charging system, the engineers also built in the technology to turn it into a starter motor. This was actually planned from the beginning.

The second technology that contributed to the SHOT was the super capacitor, which matured due to the interest in electrically powered cars and motorcycles. Capacitors can store energy and release it again, and we all know them as effective
little devices from older point ignition systems, and later from newer capacitor discharge ignition systems. Unfortunately, capacitors “bleed down” the charge after a while, depending on their design. Newer capacitor designs can hold more energy longer, making them more practical for applications like the Ski-Doo SHOT system.
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Small But Mighty The SHOT system's ultra-capacitor is very compact and weighs less than 2 lbs. This new tech is only available on the 2018 Summit.
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The SHOT capacitor box is an assembly with a number of capacitors coupled together. In the morning, the capacitor box would be discharged, so the rider would have to pull-start the engine. This is not a big problem, because with the E-TEC’s direct injection, the engine usually starts on the first pull. It takes about two minutes for the idling engine to fully charge the capacitor pack. After that, if you turn the sled off, you can start the engine again with a single push of the SHOT button. As soon as the engine is running again, the capacitor will recharge fully after only 20 seconds. Full bleed-down time is approximately 30 minutes, so if you stop for lunch at your favorite pit stop, you may have to pull the rope again.

So far, this little inconvenience has not bothered mountain riders who will happily trade it for the 20 lbs. of weight savings at high altitude. For regular trail riders used to the convenience of just pushing a starter button at any time, the extra 20 lbs. may be an acceptable price to pay for the convenience of electric start. For that reason, Ski-Doo only introduced the SHOT system on mountain machines. All other models get the new redesigned and proven battery starter system.

Retrofitting available?


Can you upgrade to a SHOT system on your 2017 model? Unfortunately, no. The SHOT system requires some fancy programming of the ECM in order to coordinate the E-TEC and SHOT to start the engine. Not only does this require a new ECM program, but it also requires an “Absolute Position Sensor” to tell the ECM how and when to discharge its pulses of energy. This cannot be done by ignition pick-ups; a more linear signal is needed. The Absolute Position Sensor is therefore a separate Hall effect sensor. It runs off a signal generator located on the water pump shaft for a more accurate input signal. This technology is not interchangeable on the regular 2017 models, so an upgrade is not possible. If you want SHOT, then your only option is to order it on a 2018 Summit.

Will it be possible to get SHOT technology in the future without the disadvantage of the capacitor bleeding down? This will obviously depend on capacitor design, but maybe a technology will be developed where a 6-lb. battery could be coupled in series with the capacitor, keeping it charged so the sled always starts on the first push of the button. Time will tell, but Ski-Doo’s new, larger-capacity charging system has opened doors to added technology!

We probably won’t see this “SHOT” system copied by other brands anytime soon, as the complete system would have to be redesigned and enlarged to match higher-capacity demand.
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