So I have a thought on possibly a cheap(ish) way of how to reduce the ambient temperature sensitivity of an MS driven EBC running open-loop. I'm posting my thoughts here to see if anyone has tried it, or thinks it is plausible.
First of all, before you say it:
- Just buy a real EBC
- Get a MBC
- MS will have this fixed soon (when?)
So here is the idea. What if you use a wastegate actuator with a target pressure that is closer to the target open-loop EBC pressure? If the EBC has to use less duty cycle to reach the desired boost pressure, then overall the system's sensitivity is reduced, and it should be less sensitive therefore to disturbances, like changes in ambient temperature. right?
Allow me to illustrate by example. Suppose that my desired boost presure is 15 psi. Say I have a 6 psi wastegate actuator (unit A), and a 12 psi wastegate actuator (unit B). All else being equal, I tune the open-loop EBC first with unit A, and then with unit B. As one would expect, unit A would require more duty cycle to reach 15 psi than unit B would. Let's say unit A takes 70% duty cycle, and unit B takes 30% duty cycle. The 70% number is based on my current EBC table tuned for ~15 psi.
Since the 30% duty cycle is closer to 0% (the 'natural' boost level of the wastegate controller), would it not be less sensitive to temperature changes, since the EBC has less 'influence'?
The ideal would probably be to use a wastegate actuator that was at the desired boost level, then only use the EBC to keep the gate from cracking open too early. Or, use a EBC/MBC hybrid setup (with a weaker actuator) to achieve similar behavior.