see thats the issue.. well with ruinning standalone anyway... there are lots of parameters that exist. but these companies offering standalone solutions have a common theme.. just send it TPS and thats it.. thats an Old-school way of handling a transmission... simpler is better right? sometimes but not always..
mechanical transmissions had a vacuum line or a cable going to the transmission. which modulated shift-lione pressure... that coupled with the springs in the valve body and increasing pump pressures with RPM created your shift patterns on mechanical automatics .. even the AT545 and MT643 commonly found in achool busses..
early electronic transmissions were just electrically shifted mechanical transmissions.. the likes of the 4L60E, E4AOD fords, etc.. the likes of these started appearing in the 90s.. they typically got MAP (vacuum) and throttle position both in electronic form sent to to them.. so they have the ability to see driver demanded engine request and actual engine load... a really nice way to control a transmission.. so even if you are at 100% load... if the drivers foot is only 1/2 way down, you can assume that the driver is fine with where things are at... as well the computer can see if the vehicle is keeping up or not... it has the VSS so it knows if we are slowing down or speeding up...
enter in the most modern of transmission integrations... full-on ECM to TCM integration... lots of things are sent through... the engine reacts to the transmission as well as the typical trans reacting to the engine..
ie in the past shift smoothness for driver comfort was handled by slow-shifting a transmission.. effectively shifting the clutches slower... this results in more wear and heat on a transmission.. under full throttle shifts were harder but still smooth..
nowadays on a modern car shift smoothness is handled by the transmission telling the engine (hey im gonna shift).. and the engine reduces the throttle till the shift is completed... (de-fueling).. the result is the trans can engage the clutch quickly and the driver feels the same soft shift they like... less wear and heat on the trans.
now lets talk retrofitting an vehicle with a new trans.. ie this conversion here..
aftermarket companies make all kinds of "black boxes" tyhat will talk to the allison TCM... ultimately you need the allison TCM... though a few are working on making their own TCM..
allisons have the ability to take in various inputs.. however they hold their communications guides close to the chest... the likes of manufacturers who buy 1000s of transmissions nbot only getr those documents but also allison will build custome TCM loads for them... most school busses are running s 'Medium Duty' load.. and there is level 1 ECM to TCM communications...
from what i can tell TPS and engine load are the 2 big ones.. in fact even if a J1939 CAN net isnt used.. a stock allison TCM can read those 2 things by analog PWM input... and ultimately thiose are the 2 single most importanbt pieces of input.. what is the driver demanding and what is the engine giving... the trans internally knows the vehicle speed rate of increase. and by its adaptive learning it learns the vehicle weight...
if you reset the adaptive fast-learn bit on a TCM.. the procedure is to go drive it like you stole it... on as flat of ground as possible, with full throttle from a stop up to as high gear as safely possible.. you have already plugged into the TCM the tire sizes, gear ratio, engine max torque and the trans ratios (TCMs are used on more than one so you tell it what its own ratios are).. now when you do your fast learn, the trans learns how quickly it can accelerate under full load.. and it knows the rate of slippage on the clutches.. so it develops the best possible shifts for you.. (and they are TERRIBLE at first as you saw in the first video..)..
and it also keeps track of your right-now driving conditions.. for instance when I take my bus out on a road that has up and down hills. where its constantly dropping out of 6th gear to 5th t omake a hill.. after a couple of them, its leaving it in 5th longer to see if im going to hit another... once it sees me steady out on speed and throttle for a bit it goes right back to 6th... anbd a quick punch and release will drop it to 5th and then right back to 6th.. so it learns...
these aftermarket companies typically feed only TPS to the trans.. or if they are feeding engine load, its a manufactured number to keep the TCM happy... so we have lost one of the key functions that the transmission can use to adjust itself.. it never knows the real engine load... it can manufacture it within itself or if said "black box" does it then it "sees" it.. but its not real... as the only thing you wire up to said "box" is the TPS... no comms link..
cruise control leaves the pedal up all the time... so the transmission is assuming you are at light throttle.. esp if the converter is locked.. the only way the transmission really measures any kind of torque input is when the converter is unlocked and it can get the spin difference.. and the TCM isprogrammed with the various parameters of your chosen torque converter.. but most of the black boxes lock your converter up quickly... as running locked as much as possible generates less slip, better economy and more efficient operation...
CAC;'s method forhandling cruise is simply manual intervention.. press the tap up or down buttons as needed,, Ok point-taken we are Driving our busses.. and so part of driving may mean intervention... i get it.. but I really dont like it... after all i have an automatic for a reason...
so MY AIM is to talk to my ECM and snag engine load data, cruise data, real TPS data and manufacture my own TPS value while in cruise mode.. my ECM sends me that data over the J1708 bus.. (the transmission recognizes J1939 not 170
... so my task is a "black box" that can push the data through to the TCM as it wants.. after all I can monitor engine load, cruise modes, and the rate of speed drop or accel. and can forge a TPS value.. as well as send real engine load... and tell the transmission my actual and demanded... thus restoring the fact I have an automatic transmission...
tuning it finely gets into a totally more in depth piece... and I REALLY love your idea of pulling my data and pushingit to google analytics.. what a super idea.. I believe i can grab any sensor data as a comma delimited file when I record it... and thus it would be real easy for me to write a script to push that data out to google
I realize this gets much deeper than most go... but you have to understand this *IS* a big part of the fun for me... while others find fun in building out really nice woodwork.. or super cool furniture they build into their busses... its *THIS* that gets me pumped up...
it was the same on my hotrods... the drive-tune-drive-tune. pieces were some of the most challenging but also the most fun!
-Christopher