Autosport Labs

I have read the Opperation Guide, which is fine in terms of how to use the MJ software, but I can't find any info on what you're trying to do with it.

My hope is to fit a MJLJ and set it up by driving the car with a laptop plugged in (rather than using a rolling road), but I don't know where to start after uploading an initial map.
eg. I understand how to change the advance at given revs, but I can't find any info on when, why, and by how much you'd want to change it.


PS I have looked through the last years threads of both the Operation and Q&A boards (they seemed the most logical places) and I can't see this question being asked before. Sorry if it has been covered, maybe it's far to obvious a question to cover here.

hi, have a look at this i put up the other day.

http://www.autosportlabs.org/viewtopic.php?t=2071


in very general terms, and anyone else may feel free to correct or refine this, combustion is a process which commences with ignition, and concludes when all the combustible material has been burnt. that is accompanied by a rapid expansion of gas and therefore pressue in the cylinder, which forces the piston down the bore and drives the crank etc. for maxium power transfer, the expansion needs to occur over a particular segment of the cycle. unfortunately, that process takes more or less time depending on both engine speed, and load. as you can only control the starting point of the process ie ignition, you need that starting point to constantly change, depending on load and engine speed, so it always finishes at the same time.

while there is an infinite number of potential starting points ie pairs of load/speed values, the map sets out an array in which the full range of values for each of load and engine speed is covered. the software interpolates between those points to choose a (hopefully) optimum value for ignition advance, at all times.

when setting up a map, you are trying to maximise power output by fiddling with the variables while measuring output. that can be on a rolling road, or by repeated road testing eg flat out speed, accereration, driving up a hill etc. one constraint of great importance is that excessive advance will at some point cause engine knock, which can cause engine damage if severe, even though that level of advance might be good from the point of view of power. overheating is another potential problem (with excessive retardation?.. cant recall). so basically, you need to set ignition for maximum performance while avoiding engine knock and heating issues.

engine knock detection is occasionally under discussion in several threads, and is not a simple matter! but i think everyone knows what it sounds like, so your ears are the first line of detection there.

regards
alexander.



regards
alexander.

If I understand that correctly, that all covers how to get an initial map.
But what do you need to do to improve on the map with road tests? (Rather than going to a rolling road.)