Idea for cheap 2 stage boost control

[Sleeper-6]

While I was sitting in class yesterday I came up with a simple idea for boost control. I was trying to come up with a way to run 24 psi with an alchy kit armed and bring it back down to whatever is safe, with it off. Maybe 16 psi or so, whatever.
I'm currently running the factory stye control hoses to the wastegate and solenoid. Now if I were to set my current setup to hold the boost at 16psi, and "t" into the line between the solenoid and the "Y" with a bleeder valve and another solenoid of some sort to turn it on and off from inside the car, should be able to have my lower setting for normal driving, and be able to throw a switch (alchy arming) that would open the line allowing air to flow to the bleeder valve, giving my higher boost setting when I feel like having some fun. What do you think?
It's not as convienent as having an electronic boost controller but should be fairly economical to do.

 

[van460]

same idea

ive done put the idea to the test, i used it years ago on my turbo coupe ford, you can run normal boost ,but use bleeder valve teed in to line. it sound cheap ,but worked i used a three way tee between the sol on cover and stock tee. i used a tee and hose ran it to inside car with a 1/8 pet cock or drain cock to a 1/8 female- female with barb fitting. you may have to thread tape the drain cock so it is tighter to turn, it is easy without it. you then can run your thumbwheel at lower timing, but still boost it where you feel safe. cost less than five bucks, but be carfull will boost with little of a turn. i used it this weekend on my new gn works great.

 

[Sleeper-6]

Cool, I figured it would work but I wanted to run it past the board for a second opinion. I would like to use this setup along with an alky kit. That way once I arm the system the boost is at the higher setting, and when disarmed due to low alky level or whatever, the boost can be dropped to a safe level. That way I don't have to worry about an absent minded moment taking out a head gasket or worse.

 

[BoostKillsStres]

I'm planning on doing the same thing as soon as I get my alky hooked back up and can find a 3 port solenoid switch. Like you said, flip a switch which activates the alky and high boost bleed setting and your good to go. I was also thinking of adding a pressure switch in the alky line which would only activate the high boost when there's a certain pressure in the line as this sould cure any rollon knock and make sure alky was flowing before going to high boost. Would just take some tuning.

Let us know if you find a good 3 port switch to use...

 

[tminer]

A little more expensive, but adds fault tolerance:

Hook a pressure activated switch into the alky hose and when alky pressure is up, it can trigger the solenoid and even increase spark advance via the ECM, with an appropriate chip (speak up you know who!).

I think that a second stock solenoid would work if you put the bleeder on the output port. You can use the available Y cable but add the switch to interupt the ECM signal to the added solenoid. The second solenoid will then follow the ECM boost curve and the bleeder will set the upper limit.

I plan to do something similar (sans the bleeder), but haven't done it yet. One caveat is that some lower boost level (under the max "no alky" level) will trigger the alky which will then trigger the failsafe which then adds the second solenoid. I can see some potential for less than a smooth application of boost, although I think that it will all happen so fast at WOT it won't be an issue. Part throttle hovering around the alky trigger point may be a different story, but may be with alky anyway.

Tom