Carburetors are purely mechanical; they can’t think. Fuel-injection systems are computerized; they can. So, why can’t an injection system tune itself rather than having to be “mapped”?
The folks at Cobra Engineering not only asked that question, they came up with an answer: the Fi2000 PowrPro, an innovative, plug-and-play module that automatically and continuously adjusts the fuel mixture while the bike is being ridden. No downloading of maps, no need for a laptop, no trial-and-error ordeals. The modules are available for all 2001-12 fuel-injected Harley-Davidsons as well as for a wide range of injected metric cruisers.
In essence, the PowrPro achieves its seemingly magical results by comparing fuel-injector pulse width (the amount of time an injector nozzle is open during each combustion cycle) with rates of engine acceleration, then—regardless of load, rpm, road speed or other riding conditions—constantly adjusts the pulse width as necessary to improve acceleration. The module takes comparison samples and reacts to them up to 80 times a second, so as far as the rider is concerned, those adjustments are instantaneous. Cobra calls it CVT, for Continuously Variable Tuning. But unlike other EFI tuning devices, PowrPro does not retain any fueling information; it’s active when the engine is running but has no memory.
For the most part, PowrPro only adjusts the mixture when the engine is accelerating; when cruising or decelerating, the system reverts to the stock mapping—with a couple of exceptions. For one, if the mixture at cruise is lean enough to cause surging, PowrPro senses those fluctuations in rpm and adjusts the mixture to smooth them out. CVT also can help prevent lean-burn afterfiring (commonly but erroneously called backfiring) when the throttle is snapped closed by adding a little shot of fuel at that point.
Okay, those are the claims; but does it work as advertised? To find out, we installed a PowrPro on a 2011 Harley-Davidson Street Glide equipped with a full exhaust system and a freer-breathing air cleaner but still running on the stock fuel map; we felt that setup was representative of a large percentage of fuel-injected Harleys on the road today. Before the installation, we rode the bike on city streets and freeways to get a sense of its overall performance and then ran it on the CW Dynojet dyno. After the installation, the bike was rolled back onto the dyno before replicating the previous street ride.
Installing the PowrPro is an hour-long task a decent home mechanic should be able to handle despite a few inaccuracies in the instructions. Using OEM-style connectors, the module plugs in between the ECU and the injectors (on bikes with oxygen sensors, it also connects between the sensors and the ECU) where it can receive the original pulse-width signal and modify it as needed. There are no buttons to push, knobs to turn or lights to observe; just plug it in and go.
On the dyno, the Street Glide made 2.3 more horsepower and just under 3 foot-pounds more torque with the PowrPro than it did without it. And while that small increase in peak output can be hard to feel, the improvement in throttle response was noticeable, and the engine reacted to fifth- and sixth-gear roll-ons a bit more crisply.
You could make a case that spending $600 (plus labor charges if you farm out the install) for such meager improvements isn’t good economics, but there are two other points to consider: 1) These results were only for this particular Harley-Davidson, whereas other models and makes in different states of tune could see greater improvements; and 2) you’ll never have to buy another PowrPro for any given bike. If you make any, or further, modifications to the engine—pipes, cams, air cleaner, big-bore kit, whatever—the PowrPro already in place will automatically adjust the mixture for optimum running.
So, if you’ve ever fantasized about fuel-injection tuning becoming a no-brainer, you’ve just met it. Cobra plans to expand the PowrPro line to include sportbikes and dirtbikes in the near future.
23801 E. La Palma Ave.
Yorba Linda, CA 92887
- Corrects mixture problems you can feel
- Corrects mixture problems you can’t feel
- Could it get any simpler?
- $omewhat expen$ive
- You can’t brag about your EFI tuning skills