NowForThe5th wrote:Particularly interesting was Matt Bailey's comments about ECU tunes and how the tuning software didn't quite interface with what was written to the ECU by the manufacturer. So, while it was possible to get quite a good tune it is very much a case of trial and error rather than being able to see the actual parameter as can be done on chips like the Unichip. His conclusion that the piggy-back style was far superior seems logical to me.
Piggy-back chips still essentially work by intercepting incoming signals, and modifying the resulting return signals. In some ways, this is no different to the ChipIt solution that is currently on the market. Unichip differs by monitoring many more of the available parameters. However, no piggyback chip adjusts the ECU in real-time, you are adjusting the Unichip. There is a subtle difference. Piggy-back chips monitor a much smaller range of input/output channels than the ECU.
This is the way ECUTEK works; The vehicle is put on the dyno, and the base tune is loaded. The vehicle is then run with the parameters being monitored in real-time. 100+ channels are monitored using the ECUTEK software. They use a dedicated, powerful piece of software to analyse the run, and the software highlights any areas for attention/improvement in the mapping. Changes can then be made based on this information, rather than trying to visually scan an entire map for problems. It eliminates guesswork via the algorithms that analyse the dyno run.
Obviously both options have their advantages; piggy-back chips can be removed and (possibly) reused, a remap can't. The piggy-back can be removed before presenting with a warranty claim, whereas you would have to go back to an ECUTEK tuner to have your OEM tune reloaded, prior to claiming a warranty issue. This may be on the back of a tow truck
The ECU remap modifies and controls many more parameters than the piggy-back, and all channels are controlled by the same microprocessor. The ECU also has hardware protection built into the PCB, which take over in the event of microprocessor failure (rare). The ECU remap is much cheaper than the Unichip, as there is no additional hardware, but I don't feel that this is much of a factor.
In summary, both have features that are appealing, and obviously different solutions appeal to different people. The important thing is that neither of these solutions are IAT resistors, or OBD-II based smoke-boxes. The OBD-II refresh rate for monitoring/controlling parameters is 100's of times slower than the ECU operates, so any claims made by sellers of OBD-II "performance" chips are fraudulent.