This is a basic information post and not directed at any paticular company, wether mentioned in this post or not.
This is one of my favourite subjects, having been in the engine management industry for 10+ years 90% of the stuff on the internet about ECU mapping makes me chuckle.
The biggest issue at the moment is people buying tools on ebay for a few hundred quid, making a website and claiming to be an 'ecu mapper' when all they are doing is copying and pasting cheaply bought software into peoples ECU's with no development, testing or real idea of what they are doing. Just take a look at these links, you can buy files for most cars for a few euros:
http://ucables.com/ref/ECU-MAPShttp://www.chiptuning-files.net/Chiptuning/chiptuning.htmlAre these files any good? chances are, the people buying files wont know how to look at the file to see if it is infact even a map file, and if they are paying a few Euros for it then thers no chance it has had any development work, or testing. But they will gladly buy this file, write it into your ECU (usually parked outside your house armed with nothing more than a laptop) and dissapear with your hard earned cash.
Then theres the whole issue about 'custom maps'. The fact is that theres very few people in the industry that can actually make a custom map correctly. Anyone that offers a custom map should have their own dyno testing facility, and the car should constantly be tuned and tested, then retuned, then tested etc.... so that you can follow the rule of getting a base level of the parameter that you are tuning, changing this parameter and then re-testing to see the effect of the change. I had a customer wanting a dyno test last week that had a 'custom remap' done outside his house for £150, the customer seemed delighted that the guy had completed this 'custom' map in just 25 mins and that the car felt loads better to drive. The dyno showed the map to be exactly what I had imagined, they had literally changed just 1 map (fuel pressure) and although the car had gained power from standard it was extremely 'peaky' and extremely smokey (it was a diesel).
After looking at the map for the customer we realised that the harware and software number of the file used wasnt even a match for the ECU fitted to the car! So all that had been done was the good old 'copy and paste' method. After checking these ECU identifications, as I expected the 'tuned' file was actually from a completely different car. Was there anything 'custom' about this remap? well, yes. they had customised his ECU with another cars file, so in a way it was custom to his car, but is that what people expect with a custom remap? I think not and most would agree with me but by putting the word custom infront of the word 'remap' the general public will think that its somehow better.
will continue in another post....