 |
|
|
1985-1998 [Subscribe to Daily Digest] |
[Profile/Gallery]
, Sat, 5 Jul 2008 15:11:23
Members do not see ads below this line. - Help Keep This Site Online - Signup
Well This way I see it Both are duty cycle based.
The on/off pulse can be sort or long depending on what is required. This is PWM duty cycle
I'd also worry that the APC solenoid will take out the transistors in the ECU. I'll bet the resistance may be the same, but the inductance of the APC vs. BPC will be different - putting pulses into inductors can make for some interesting issues.
I can measure current draw and it is small. The ECU/APC 3amp is fused so the FETs will not fry.
Is it working now? Yes It works perfects like my SPG did.
Will it reduce boost if you start knocking? The car does not knock. It will reduce boost if it does.
I have full boost with cruise control. Given the control valve is No-op
If you put your foot on the brake, does the boost reduce to Base? I will check, it appears to. All I want to do is limit boost so I will not go into the RED zone. The APC valve does this without fail.
If so Please explain why I get control boost to redline /// and it holds (no knock) until 4500rpm then tapers off just like the 900s do. No Knock is present.
To get PWM:
The three wire BPC valve has two coils, and the position of the valve is a function of the pulses the ECU gives it. Pulse one coil more than the other, and the valve moves that way; pulse each coil the same, and the valve stays put.
Pins 1,3 are ground reference via FET for control of the coil on/off function.
Pin 2 appears to drive the pulse width and pins 1,3 fine tune the PWM for and unbalanced PWM control.
The 900 system is also PWM it only drives one coil for duty cycle and is balanced via a spring.
It is just like a stepper driver, The driver send pulses out(ref duty cycle) the ground ref is LH, RH direction. The APC only drives one direction the spring takes care of the other. The BPC has no springs so it fail open or closed. The APC fails closed and base boost always.
Both 900 and 9000 ecu send Variable Pulses out for the APC and BPS. The BPS has fine control via Ground Ref FETs the APC does not which is fine with me.
posted by 24.4.96...
, Sat, 5 Jul 2008 15:11:23
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
