Power Commander Versus ECU Remapping

This is the one question I get asked the most often when it comes to street and track bike tuning. So I’ll give you my perspective. I’ll start by saying they’re both excellent at what they do. And maybe the best way to go about answering this in a way everyone can understand is to describe what they both can and cant do.

Power Commander (PCV, Bazzaz – Piggy back Fuel Controllers)

  • They intercept and change the signal from the Engine Control Unit (ECU) to the injectors, adding or taking away fuel during combustion. This alters the Air Fuel Ratio (AFR) of the bike, more fuel equates to a richer AFR, less fuel a leaner AFR. Rich AFR’s will present the following issues.
    • Dirty exhaust pipe or soot and excessive smoke (unburnt fuel)
    • Cooler combustion and exhaust temperatures
    • More emissions to the atmosphere
    • Less power
  • Leaner AFR’s will present these issues
    • Too lean – high combustion and exhaust temperatures, engine damage – holed pistons etc
    • Detonation

ECU Remapping

  • AFR’s. The ECU’s internal settings or parameters are edited so that the AFR’s are changed to bring them closer to the ideal 14.7:1. Most tuners will aim for anywhere between 12.8-13.1 at Wide Open Throttle (WOT) as this provides a safety margin. ECU remapping can achieve this without hacking into the bikes wiring or having additional components strewn throughout the bike by altering the existing factory maps.
  • Timing. Timing tables or maps can also be edited. Altering (advancing) the bikes timing is where more power can be safely gained over border line AFR’s. Fuel controllers can not alter a bikes timing. Factories sometimes install timing retards in the first three gears of their bikes to lessen the power hit. People sometimes fit Timing Retard Eliminators (TRE’s) to combat this, again more wiring, modifications and components to install. When an ECU is remapped, these retards are simply removed and you’re good to go without the need of a TRE.
  • Settings. There are many settings and limits which can be changed or removed when an ECU is remapped. Some of which are listed below.
    • Top speed limiters can be removed
    • Idle speed can be increased/decreased
    • Rev limits can be increased, this sometimes lets you pull a gear that bit longer before having to shift or have the rev limiter savagely cut in adding to your lap times.
    • Thermo fan cut in temps can be altered
    • Deceleration maps can be altered giving a much improved throttle transition and removing that dreaded snatch.

Proponents of Power Commanders are usually tuners (or customers of) who have a dyno in their workshop, they will fit your fuel controller then give you a “custom tune” to suit your bike and its modifications. They do this by adjusting the fuel controller until they are satisfied with the AFR’s throughout the rev range of your bike, you then give you a print out that shows the AFR curve as well as power and torque curves. Nice to show your mates. The issue here is that it i

s very easy to manipulate the results of the dyno graph to show a much larger gain than you actually got. This is a problem throughout all disciplines of automotive tuning. It has to be said though that there are decent and reputable tuners who don’t do this, so don’t be afraid to ask if you go down this path.

These tuners will argue that manufacturing tolerance deviations will produce bikes that are all profoundly different and require custom AFR tuning. My take is that modern manufacturing processes now punch out bikes that are so closely cloned that I’m not sure this is such an issue any more, lets face it, the bikes all pretty much feel the same off the show room floor.

ECU tune developers will take a bike and tune it both on the track and on the dyno in every conceivable state of modification and develop tunes for each of these, for example there will be an optimised tune to suit an R1 in stock trim, then another tune developed for the bike with a slip on, then another with a full system and so on. So the end user will get a tune pretty much customised for their bike if they tell the tuner exactly what they have done. And there is always a factor of safety built into these tune files to ensure reliability. I’ve had customers put their bikes on a dyno after an ECU remap and their AFR’s are just about bang on. So the tune developers really do get it right.

Conclusion

The optimum setup would be to have your ECU remapped, then fit a fuel controller and have it dyno tuned to get your fuelling precise. This is what all of my race team customers do. For the average punter though, if  you had to choose one, the ECU remap would be in my opinion, the best value modification you could do for your bike – hands down.

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