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John at J&S John at J&S is offline
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Join Date: Dec 2005
Location: GARDEN GROVE, CA
Posts: 143
Rev limits and boost retard settings are made with the aid of test points on the front panel. For example, to set a 6350 RPM limit, adjust the knob until the corresponding test point reads 6.35 volts. This can be done with key on, or engine running.

The boost retard "Start" and "Rate" settings are adjusted similarly. The boost retard "start" point can be set from 0 to 10 psi. If you have determined that you don't need boost retard until 6.5 psi, adjust the start knob so its test point reads 6.5 volts. The "Rate" knob adjusts how many degrees retard per psi (beyond the start point). The range is 0 to 2 per psi. For 1.25 degree retard per psi, adjust the knob until the test point reads 1.25 volts.

With 15 psi and the above settings, boost retard would begin at 6.5 psi. Total retard at 15 psi would be (15-6.5)*1.25=10.6, but software rounds it up to 11.

The first system shipped last week for use on a twin plug car, equipped with a MoTeC. I haven't finished the other drawings yet, but the unit can trigger from the stock magnetic pickup, and output an ac signal to the magnetic trigger input of the Bosch CDI. Basically, cut the stock magnetic trigger cable and connect the unit between the cut ends.

Note that the Bosch CDI makes spark on the falling edge of the magnetic pickup signal. Mode switches on the front panel let you select input and output trigger polarity.

Old 07-18-2008, 10:08 PM
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