STVA Secondary Throttle Valve Adjustment
In shop ordercomment add "Please instead of internal DBW, add additional 2A 4-wire bipolar stepper driver controlled from some ECU PWM output". (same price as internal DBW bridge, select that for price).
Suzuki GS-F 650/1250 (ccm3)
Secondary Throttle Valve
- 2A 7 Ohm bipolar 4 wire stepper for intake pipe cross-section area control
- 256 steps enough? No, appr. 1200 steps
- or more steps needed? Please check if available. We'll see
- step down to 0 (actually fully up?) at powerup/ Ignition ON->full open-> set 15% position before/during start (as set for 0 RPM)
- step to command position after that (PWM input or digital input)
Current and Power... Each coil is 2A * 13V = 26W... The stepper total dissipation is 2 x 26W > 50W stepper that must NOT be powered continuously... IT WOULD OVERHEAT
- stepper must be powered DOWN when it reaches target, or better: lower (appr. 0.5A 7W/coil) holding current should be applied...
- Appr 30..50% current should prevent premature damage to throttle stepper motor
Analog input 0.5V .. 4.5V (supplied from 5V)
- 0.5V .. 4.5V
- mcp3208 analog input for logging.
6+2 IGBT
- 2 ignition recommended: EC36/34,36 (ch2,3) Wasted spark.
- power ign outputs: 4 free remaining
- logiclevel ign output controls "Boost PWM" => STVA throttle-stepper position (available on EC36/pin... while also commanding the throttle controller)
- 1 logiclevel ign => stepper wire (2A) original trace cut
- 3 p259 EC36pins => stepper wires (2A) original trace cut
- colors: GW,
- colors: PY
- EC18/pin1 mcp3208ch0 throttle feedback (TPS2). Can also be logged by v3 main processor
2ns RS232 not needed, (1 RS232 on EC18/14-15... standard)