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The pressure at the manifold can be released in bulk which will not interfere with the MAP sensor getting an accurate reading of the pressure. So a pop-off valve would be perfectly safe. ...but not inexpensive!
A constant electrical offset of the MAP sensor can be made and the ECU will re-adapt to achieve proper mixture control. This would allow the spikes to be ignored by the ECU if the base pressure was not cranked up too much.
A combo of the two methods above might work well, as a small pop-off valve could be fitted into the IAC hoses for an easy install.
Any method that reduces the mechanical preload on the wastegate actuator will help the actuator rise time. This can be pressure applied as you suggest, but a needle valve bypass for the MBC would work just as well and be simple to adjust. Similarily, the wastegate actuator adjustment could be softened to get a similar effect. So a combo config with a manfold source tap would be good. The preload pressure tap for the needle valve could be from the compressor or the manifold. One can argue about which would be better, but both configs should be evaluated.
Bleeder valves or BPC valves provide a slow rate of rise which is easy to control. A bleeder/ball-spring combo should allow for a better state than the MBC's in cold weather.
Note that at some point the exhaust manfold pressure acting on the wastegate valve face will be a force to be dealt with itself.
The length of the loop with a manfold pressure tap does create a time delay that cannot be dealt with by improving the rise time of the actuator. So some overshoot is to be expected. This is where the pneumatic preload from the compressor might help in providing a preview of whats comming through the pipes. But this same mechanism could lead to some boost taper itself, as this presure source will rise with CFMs.
posted by 207.43.195.2...
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