MSD 7562 Programmable Launch Boost Controller Installation - Manual (Page 17)

INSTALLATION INSTRUCTIONS 17
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TEST EXAMPLE 7 - FIGURE 12
Figure 12 shows a high-speed test run on the chassis dyno with the target pressure set to 18psi of
boost. Here the turbo ramps the boost pressure to just under the target at 17.8PSI and then drops
slightly and continues ramping up to about 17psi at the end of the run. This car was not capable of
developing and maintaining the target pressure of 18psi on the dyno. The PWM values show that
at 4.3 seconds the waste gate was fully closed (PWM=40) and only climbed to 17psi by the end of
the run. The PID was tuned at the near optimum values on this run and if the target pressure were
set for about 17psi it would have regulated very good.
After the optimum P and D terms have been programmed, the I term can then be optimized.
Increase the I term from zero to about 10 and retest. When the P - D pressure ripple is minimized
the I term is optimum. Too much I will cause larger P - D variations with the boost pressure.
Figure 12