If you understand how an ECU works and how a 'map' is used by the ecu, and also - for example - the multiple map system (for example 24 maps in an old L series DCU, then I can attempt to explain to you how a remap works. And yes, I have remapped systems both on a rolling road dyno and on the road from the passenger seat using real time data. I have used Weber Alpha and also Megasquirt systems. I also have experience of closed loop Lamda assisted mapping.
If you are not familiar with the standard model for an ECU then it would be difficult.
I also never mentioned 'blatent lies', I said 'poetic license'. If you read most 'fudge box' sellers sites they will tend to play down the remap and massively over-inflate costs of such, and also benefits.
Any knowledgeable re-map specialist would throw their hands in the air if the 'user' suggested adding a feedback circuit 'fudge box' on TOP of the remap.!. It is simply crazy.
I am not saying the 'fudge' boxes do not make a good difference, I am saying that they are a general compromise, they tend to be much more expensive than a very good quaulity remap and they are certainly not as optimised for your engine and usage. The fudge units will tend to waste fuel also as they cannot be optimised over the full range of usage. This is no problem to many users. If you wonder why I use the term 'fudge' unit or 'fudgers' it is simply because that is all they do, they trick (Fudge) the ecu into seeing a different reading from normal hence altering an output - some of the first units tricked the CTS, then the Air metering flap in the Motronic systems - and so it progressed. The modern fudgers are not too much more sophisticated. Anyone selling a fudger for the L series for example is simply selling a virtual copy of the EVRY mod which costs about £1.50 at most to do. Some so called 'digital units' have a crude mapping system built in for the fudge only which a good analogy would be a graphic equaliser preset selection on your ICE system. a knob to select various'curves' - slightly better than linear but not much.
I love experimenting with my L series. But !!! - I am working with Kris (a most respected expert in the field) at
http://www.dieselpowered.co.uk/ to produce a map for my modified L series unit. I also have several ECUS so can replace the modified with existing one if I wanted to (for exmaple whislt tweaking the map - which Kris will happily do.)
I am also working on a multi map system that is switchable from Kris map to normal map etc - using a Micro controlled unit to replace the two on board eprom units.
So, yes I am - IMO - qualified to comment.
Joe