What is re-mapping / power commander

I’ve been asked what power commanders do, or why the tuneboy programme is better and how they both work, so have written this to help.

What is re-mapping or re-chipping?
The most difficult concept to grasp for most people is that re-mapping/chipping is merely engine tuning, albeit that it’s being done electronically rather than mechanically (as in the old days of carburetors and distributors). A chip is simply an electronic storage device which is located on a circuit board inside the E.C.U. (the Engine Control Unit). The chip contains values in a binary form which the E.C.U’s main processor (another device on the same circuit board) can understand and use to control the engine.

Each value inside the chip is held in its own separate position (known as an ‘address’), and when a bike is re-chipped, what we are basically doing is altering the values at the groups of addresses that control primarily fuelling & ignition timing. These are known as maps, hence the often-used term ‘re-mapping’. It is these maps which we massage in order to tune the engine.

Methods used.

There are three main methods used for this, the first is to physically change the chip, the manufacturer (or aftermarket company) will make a kit, either pipes & chip or air filter/ pipe(s) & chip, it’s normally spec’d as a “race kit”, this will either be a complete change of the ECU unit (just unplug and plug in the new one) or a change of the chip on the board in the ECU.

These have a fixed map which doesn’t have any noise or emissions limitations and are optimized for maximum power.

The limitations of this are that the values are fixed so you can only have what is already on the chip, better than standard, but not individualized to each bike.

The second is direct remapping of the ECU, through an interface plug on the bikes loom a control interface is connected (tek/yoshi box or tuneboy being the well known ones) and the values held can be dynamically changed. This means every value to ECU holds can be set for any modifications to the bike, then tuned (in conjunction with a dyno) for the very best power/ throttle response you want.

Limitation, expense a yoshi tune is anything from £25-£100 a time, and although the Tuneboy is only £250 ( for the complete programe and interface cable) you do need a laptop (only available for Aprillia/Bennilli & Triumph).

The third method is “output modifiers”, these are devices which sit inline with the ECU (power commander/ big shot, loads of others).

The standard ECU receives input from the bikes sensors and using the inbuilt values sends out signals to control both fueling and ignition, these in turn go though the attached device and are “modified” using a second set of values (Map) then passed on as if coming directly from the ECU.

Limitations, some of these are fixed map versions much like a re-chip, but in a separate box, whilst others can have maps loaded on, however the maps are less dynamic in nature so the degree of tune will never be as good as a direct remap. In order for the new map to be applied the device has to be left attached to the bike at all times, removing it returns the bike to standard.

Cheers Mark.

That’s a great explanation mark, well done!