oldManTan

I've been just browsing for a way to control the auto transmission on my SC400. it's a 2 shift solenoid system so it works with quite a few transmission controllers but they're all so damn expensive ranging from 400-800. the Suprastick i'm not even sure is sold anymore and it's a pain to find one in the classifieds.

i have an arduino uno and making a cycling program that goes from S1-on S2-off > S1-off S2-on > and so on to shift with buttons would be pretty easy i think. anyone got any input on this or help with wiring? is the transmission controlled by the main ECU or does it have its own transmission controller? maybe i could even tap into that and somehow control it.

tiguy99

Have you checked on the GS400 guys?
Saw a thread earlier re: the eshift retrofit for those doing Aristo swaps....you may find what you need going that route

oldManTan

thanks for the tip, i'll check it out.

LoveSCs

iTrader: (2)

OldManTan,

It's funny how alike you and I think. Everything from the 3d printing projects, to the tablet, to a lot of your other things that you mention and/or start on But in any case, I have (had) the suprastick on my 1JZ SC400 (now in the midst of finishing up CD009 swap). I had always thought about doing this as well. But, it gets a little bit more complicated than just solenoid control. To do it right anyway...

The toggling of some Arduino outputs for the shift solenoids is the easy part. The hard part is integrating the torque converter lock up solenoid properly. TC lockup occurs in third gear and around 30MPH. This requires a vehicle speed sensor input and the logic within the Arduino to correctly determine speed. Then, the TC unlocks when the brake is applied, which would require a brake input signal and logic (although you could I guess turn the TC solenoid off at a certain speed as well). Another thing you would/could want is downshift protection so that you do not over rev your motor in a down shift. This would require a crank or cam shaft angle sensor input and logic.

I had my suprstick wired with a relay in between the ECU and transmission so that I can switch between letting the OEM ecu automatically shift if I just feel like cruising. Or, I could flip the switch and control the gears manually through the suprastick.

The one thing about the transmission is that it does not have engine braking in "D". Only in L and 2. The engine braking function is hydraulic and is not activated with the lever in D. So, when you downshift and take your foot off of the gas, the motor will drop to idle level. Then, will not grab until the motor matches the TC speed.

So, what I have always wanted to do was make a trans controller as stated above, but also have controlling function for a little high speed linear stepper motor/slide to move the shifter back and forth between L - 2 - D. But just never got around to it.


Now, please keep in mind that all of the above is relative the 1JZ A340LE, which may or may not be the same operationally as the SC400 trans.