The good ole days when you pulled your carbs out on the bench to tune that lean spot at WOT, wasn't really that long ago. And if you're still a hardcore backyard tuner you've probably not given up on the carburetor skills just yet because your faith in the reliability of Fuel Injection systems has not proven to win your loyalty. Oddly, if you've looked under the hood of any late model sled, there's just not that much to see, its all been hidden away from us. I find it rather amusing.
If you've been following the trends in Fuel Injection systems in the past five years, you've certainly heard many speak of the need to use fuel controllers such as Dynojets Power Commander, to improve reliability and overall performance today's modern snowmobile engines.
While some may wonder why you would ever need one, especially with the number of sensors now used on sleds to calculate ideal fuel needs no matter what the temperature and elevation.
Technology is marvelous indeed, however, if you have any inclination to tweek your sleds performance, don't be surprised if stock factory settings are not be up to the task. Even if your considering something as simple as a clutch kit, or a deeper lug track you could be adding load on your engine that may and probably will require some tweeking of fuel delivery to get every bit of that power where it belongs.
Other power adders like pipes, high volume air intakes, turbos and high compression heads would certainly require more fuel and if you have a fuel injected sled, you will need purchase a fuel controller.
I was first introduced to fuel controllers as a result of the poor performing and hardly reliable CFI 4 800 engines that Polaris ran from 2008-2010. By the way the original configuration in 08-09 with the higher compression stock head was a power house, unfortunately Polaris just couldn't pass emissions without leaning out the mid range dangerously, hence the update kit in 2010 and numerous reflashes to detune the engine and increase the sensitivity of the knock sensor.
If you currently have a CFI 4 800 and you've not installed a fuel controller you've either spent a lot of money on rebuilds or you love to gamble every time you ride whether or not you'll be getting a tow home.
Do yourself a favor and buy a Power Commander right away, you'll gain substantial HP and add a level of reliability and confidence you've probably never had before in that engine. If you see one of these sleds for cheap and its a clean sled, you'll get a bargain by bolting on a fuel controller with the right map and you won't be disappointed in the power these engines are capable of delivering.
One of the cool things about fuel controllers is that it made tuning a very clean and easy task. You basically plug your sled into a computer and tune throttle position, RPM and % fuel delivery using software.
If you're really keen you'll have a subscription to Dynotech Research and get maps they help build on the dyno so you can plug and play. Maybe you like tuning so much that you build your own maps from scratch, which is fun too. Whatever way you tune it, you still have to use common sense and know how to properly read your plugs. If you really want to play it safe while tuning, you can purchase a variety of instruments to monitor and record your engines performance while you ride, there's even a tool called "Autotune" which basically builds an optimized fuel map for your sled based on your riding conditions and style.
Albeit most snowmobilers just want a gas and go solution to cure their sled addiction and the concern for performance is not a priority, however I would strongly argue that an ounce of prevention is better than a pound of cure for those of us who like to tinker and tweek with performance or choose to buy one of those unreliable fuel injected stock engines and hope to get your money's worth.