Originally Posted by Karl
LOL disagree away, I'd love to see what people understand about transient fueling anyway, and then after that I'll start to discuss cold start and boost control mapping!!!
Karl without a doubt, im utterly positive that i dont know anything about transient mapping that i could teach to you mate
To me the term transient mapping refers to the way in which the ecu responds to changes in the environment, so for example if you are at 3000rpm at 42% throttle for a period of time, thats not transient fuelling, thats just a load site (or interpolation between two load sites), if you then press the throttle down to 60%, then for that small amount of time that you move the throttle and just after, thats transient, and relies on more than just looking up a value in a table from the TPS and RPM or whatever, as taht doesnt allow for change, when you then continue to set at 60% throttle its then not transient anymore as things arent changing as much.
Thats (a very cutdown) version of my take on what transient fuelling is all about, and i understand the problem with lambda is that its very much reactionary technology, ie it only allows the ECU to alter the fuelling to be correct AFTER its already got it wrong in the first place and that problem has been spotted by the lamda sensor, obviously the time taken for that to happen means that if things are still changing then the data will be out of date by the time the ECU gets it, and therefore of far less use to transient situations, but obvioulsy the quicker the ECU is and the faster reacting the sensor is the closer it gets.
With regards to cold starts, dont even get me started on that one, i will be 100% on your side with that, people REALLY dont realise just how much fucking effort it takes to get an engine to cold start in totally different circumstances every day, and its NOT something that a couple of days on the rollers can sort out, it takes so much development from manufacturers to get it right in the first place that you really cant hope to just bolt on an aftermarket ECU and get close.
Thats why its SO much of advantage to go to someone like Mark for autronic that someone who doesnt have years of experience knowing how to set it up for such situations.