hange is inevitable-if you don’t think so, just try to find a carburetor on any 2007 Harley-Davidson. You won’t, because the entire model line has been converted to fuel injection. That’s a good thing in terms of throttle response, tailpipe emissions, and gas mileage, but maybe not so good a thing in terms of tuning an engine to run right with high-performance equipment like cams, air cleaners, pipes, and big-bore kits. With carburetors you swapped jets, needles, slides, and nozzles until you got the performance you wanted across the rpm range-all pretty straightforward and hands-on. But since the heart of a fuel injection system is a mysterious black box full of full of what, exactly? The job’s a bit tougher. Or at least it was until now, thanks to Dynatek’s new FI Controller.
     The basic difference between carburetion and fuel injection is that carbs use fixed metering, while fuel injection can, to some extent, adjust itself in response to external conditions. For example, many FI systems can sense temperature and barometric pressure, and use those measurements to fine-tune fuel delivery to the engine. The result is more accurate metering than is possible with a carburetor, whose fuel delivery is affected primarily by engine rpm.
     While the number of variables used by fuel injection to adjust fuel metering makes it more accurate, it also complicates performance tuning. Some fuel-injection tuning units require you to download a fuel map from a website to replace the map the unit comes stock with. Every subsequent change to the engine requires a new map. But Dynatek’s FI Controller can be tuned almost like a carburetor, but without getting gas on your hands.
     The FI Controller comes with three pre-programmed base maps, which can be selected simply by turning a single adjuster. Base Curve 1 is for stock or mildly modified engines, such as those with basic modifications like air cleaners, air filters, and slip-on exhausts. Base Curve 2 is for engines with bolt-on mods like a full exhaust system, and Base Curve 3 is for engines with major modifications like cams and big-bore kits.
     Once you select the base curve that’s best for your engine, it’s time to fine-tune the fuel delivery using a trio of potentiometers. Each of the three potentiometers corresponds to a certain rpm range. Low is for idle to 2000 rpm, Mid for 2000 to 4000, and High for 4000 to 6000. To richen the fuel mixture in a given rpm range, turn the adjuster clockwise; to lean it out, turn it counterclockwise. The total range of adjustment is plus or minus 20 percent. Because the potentiometers can be adjusted incrementally, they’re more accurate than the push-buttons on other units, which make changes in big steps.
     The ability to both richen and lean the fuel mixture sets the FI Controller apart for other systems that only add fuel to the stock fuel map, and makes it the ideal choice for some set-ups like Harleys with two-into-one exhausts, which work best if you lean out the mixture in the lower rpm range. Because the FI Controller comes with a base map and two additional maps, and gives you the ability to add or subtract fuel from each in three different rpm ranges, it’s able to accommodate a wide variety of high-performance options from simple carb and air-cleaner changes all the way up to fire-breathing big-bores.
     The simplicity of the FI Controller compared to other fuel-injection tuners is obvious-no PC required, no trying map after map to find the one that works best with your particular combination of engine modifications. You can even make adjustments on the road, away from your garage, with just a screwdriver. Carrying a passenger, or heading for the mountains? Just pull over, re-set the FI Controller, and you’re ready for that added load or the thin air of the high country.
     The FI Controller’s OEM-style connectors plug into the bike’s stock system at the fuel injectors (some models have a T-splice for the throttle position sensor) so the system can be installed in only a little more time than it takes to remove and replace the fuel tank. The compact control unit can be mounted anywhere on the motorcycle, either hidden away or placed where it can be easily adjusted any time. Dynatek’s FI Controller comes in applications for Harley-Davidsons, metric cruisers, and even ATVs-check www.dynaonline.com for the latest applications. They’re all available from Drag Specialties.