Manual Boost-Use of Two parallel needle valves with solenoid bleed control-Thought?

[mudski]

Thinking out loud - Manual Boost using two needle valves in parallel with elec solenoid bleed control

08 GU Manual CRD, Full NADS (EGR block “solid plate”), TIG I/C, 3" Pipe, snorkel, stock turbo & air box.

ECU Remap (ECPT tune spec - max Boost 20-22psi/AFR 22:1)

Manual boost control (single Dawes/needle). Current max boost of 21psi with cruise boost 17-18psi.

Prefer to have the ability to independently access either of three separate pre-set spool rates while retaining the same max boost (via a single Dawes) of 21-22psi for all the three pre-set spool rates. This should provide the AFR (22:1) when either of the three pre-set spool rates are used.

From using manual boost control with remapped ECU and adjusting needle on the fly, I have found three different spool rates sets that meet my requirement:

Sweet Spot – Currently set: max boost 21psi with cruise boost 17-18 psi (preferred needle sweet spot with good spool rate/pwr responce). Needle open 1.3 turns
Max Spool – With needle fully closed, max spool rate max boost 21-22psi
Hwy Eco - out on open roads (hwy easy cruise), run cruise boost of 14psi but maintain max B 21psi (laggy but provide economical fuel usage and does not work the turbo consistently at higher speeds). Needle open 2-2.5 turns

Propose to use:
Only one Dawes for max boost (currently 21psi).
Two needle valves and each having a vac bleed inline 2 port N/C elec solenoid controlled by a SPDT toggle switch.
Both needle/solenoid valve sets be installed in parallel but be operated independently of each other.
Hook up SPDT toggle switch (dash mount) to independently select either of the three different spool rates on the fly.

The switch in the:
•up position (ON) will provide Sweet Spot (this needle solenoid open only)
•mid position (OFF) will provide Max Spool (both solenoids closed)
•down position (ON) will provide Hwy Eco (this needle solenoid open only)

Have seen the 2 stage Dawes set up but thought this method of manual boost control may be a good option.

Welcome comments and advice.

I can't see the advantage of having multiple spool up rates. Having a slower spool up that what its ideally set at will only cause higher etgs and poor performance.
And having faster could bring on limp mode.
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