A loose actuator arm (or weak spring) lowers
ultimate boost potential. You might get only 15 psi at max (with the actuator
unplugged). In that case, you want to shorten the actuator arm to raise the
boost. A tight actuator (shorter arm) gives a higher maximum boost (but
encourages more boost creep, so don't go too short).
If your turbo goes past the boost level you'd like (too high) when you unplug the actuator (which MAXES OUT your boost), you want to lengthen it's arm to reach your correct high boost goal with the actuator unplugged. Then the boost *will not* go past your desired boost maximum. You need no bleeds, no G-valves, and no manual boost control of any kind to hold your favorite high boost level. This works well only for guys and gals who desire to run just a few psi less than maximum boost. If you try to lengthen the arm enough to run 10 to 15 psi less than max, the arm will be so long that the wastegate won't shut!
Simply unplugging the actuator at the track will give you quick spool up to your favorite high boost setting. Of course a simple cheap solenoid valve will "unplug" the actuator for you when you turn it on with a switch. The solenoid valve vents the actuator can to atmosphere, *just* as if you unplugged it by hand.
Say you like 22 psi... You simply adjust the actuator length to get your desired 22 psi (or whatever) with the actuator unplugged, and it will be a no-spike 22 psi!! No G valves to get dirty and be cleaned; no bleed valves to adjust and re-adjust. No accidental forays to 30 psi! Less melt downs; less detonation, less headaches, and almost maintenance-free.
I threaded the ends of the actuator rod after cutting it apart. Then I picked up a "coupling nut" in 1/4-20 size. I then assembled the arm, which is now similar to a stock T3 adjustable arm.
I changed the length of the arm to get 25 psi with the acturator unplugged. You can set yours for 19 psi, or 23 psi, or whatever. Once the high boost is set, all you need to do to get your "low" setting for launching and street driving is this:
That's all there is to it; after you wire the
solenoid, you have a 2 stage boost control that really works. VERY quick spool
up; no spiking; cannot overboost by accident! This set up will give you a "low"
of whatever your new minimum boost is... if your minimum boost becomes 5 psi
after adjusting the arm length, then 5 psi will be your "low" setting. After you
get through the trouble to set the best arm length for yourself, this is the
simplest and most effective 2 stage boost set up ever devised.
For those who insist on setting their own "low" setting to 8 psi or 11 psi, or whatever, just do a little extra work, and you will come up with a "normal rise" low, or a "quick rise" low setting.
2 stage with quick-rise "low" setting
2 stage with "normal" rise low setting
After you've chosen the ideal set up for yourself, wire up the solenoid as follows:
OR, my favorite:
The 2 wires coming out of the solenoid will most likely NOT be black and red! I just used those colors for my illustration. In reality the colors of the wires is not critical; either wire can go straight to 12V positive, and the remaining wire can go through the switch/switches to ground.
Remember, shortening the actuator arm
raises the boost you will get when unplugged, and
lengthening the arm lowers the boost you will get when
unplugged. If you know that you will need to be shortening your arm, hacksaw
1/4" to 1/3" out of the arm and toss it away before threading the ends. If you
know that you will need to be lengthening the arm, make one small cut with the
saw to leave almost the entire arm there.
You can fine tune the arm after installation by taking off the 2 actuator bolts and rotating the entire actuator can & bracket. Clockwise to raise the boost, and counter-clockwise to lower the boost.
If it's easier for you to remove the clip and rotate the arm, then go for it. But most will appreciate being able to rotate the whole can, which leaves the pesky little clip out of it.
When you're done, you have a great 2 stage boost controller, and you never have to worry about going too high with the boost by accident; it will not go beyond your desired "high" setting! : )