COMMONLY ASKED QUESTIONS
- My SF-901 has an S&S 124 cu.in. V-twin motor running and cannot get the motor to hold a constant rpm. I've tried various settings between the capacity valve and the boost valve, but the solenoid seems to wander when pulling down to starting rpm. The motor creates approximately 140 lb · ft of torque and 120 hp.
The difference between manual control and servo control is that we close the load controller loop onto the tachometer. The computer in the console attempts to control the motor to rpm using the servo valve. The most likely cause is an intermittent rpm signal to the console.
Remove the tach pickup (very carefully) and inspect the tip for cracks or obvious damage. Pins 1 and 2 should read approximately 150 ohms, although the resistance is not critical.
- Push a long, thin, common screwdriver down the hole of the tach pickup and engage the 60-tooth tach gear.
- Tap the gear using the screwdriver and a small hammer. If it budges, then it's loose and you must go in through the front of the absorber (remove the motor, input shaft, and drive hub) to tighten it.
- You could try to run a manual valve ramp test which closely simulates the accel test. It does not matter what the engine rpm is because it simply decays the servo valve from wherever you place it to wherever the upper rpm is reached.
Contact SuperFlow Customer Service if you need help with this procedure.
- If the above SF-901 problem were due to an intermittent rpm signal, wouldn't that also be apparent in the rpm indication on the console?
The control system needs to respond much faster than the console display could ever respond. The display is slow and may not show the intermittent signal. You can, however, watch an analog representation of the rpm signal on pin 13 of the 802 board in the console. SuperFlow creates a signal that is directly proportional to the tachometer frequency.
- 0V = 0 rpm
- 10V = 10K rpm
The control system controls to the "analog tach." Use your voltmeter to watch it with the engine running. It should be steady with the rpm signal. The 802 board is the small board to the right of the large Central Processing Unit (CPU) board. Count the edge connectors from left to right. Edge connector #13 is your measuring point.
- I just finished testing on a SuperFlow dyno. How can I view my test data?
- Can WinDyn be installed on a Windows 7 computer?
Yes, but it must be Windows 7, 32-bit. Here are the instructions