From the tech. files of POOMA U. :D

[ottawa rogue]

ok gang, i had a random thought. a lot of you use multistage boost controllers
to control off the line boost when drag racing, right?
how about using a regulated comp. air source to "preload"the wastegate can?

say you had a can that would open at 15 psi, and you loaded it with 12 psi of pressure, that would allow you to launch on 3 psi of boost. run this through an air solenoid with a button, and you could launch and then pick up full boost when you got off the line. with the right setup you might even be able to "roll" the boost on progressively

whaddya think?

[Frank]

Not a bad idea... except it needs some further thoughts... you would need about a liter canister to pressurize AND you would need a solenoid before the canister to engage it.


Frank

[8valves]

That's similar to how most standalone systems control boost on external wastegates with dual ports, ie any good quality wastegate.

They use boost pressure on top of the valve and below the valve to control the gates action for EXTREMELY precise control.

AM

[ottawa rogue]

Not a bad idea... except it needs some further thoughts... you would need about a liter canister to pressurize AND you would need a solenoid before the canister to engage it.


Frank

that's pretty much what i had in mind, a small reservoir with an air solenoid, teed into the wastegate supply line.
and depending on how much boost you develop and the pressure of your tank, you could run another line with a check valve from the manifold to the reservoir to recharge it while running down the strip.

8valves, this would allow you to set a "launch boost" before you ever got around to making boost

i'll have to sit down tonight and draw a diagram to explain it better:D

[lametec]

So your theory is that when having two pressure sources of different pressure teed with each other, they'll add the two pressures together? I'm thinking you'd just blow most of your 12 psi into the intake manifold against the 3 psi boost. In effect, you'd have a 9 psi pressure on the hose from the wg to the manifold. The wg would still only see 12 psi (assuming your "canister" could supply enough cfm to keep the pressure up, as it would all be escaping into the manifold).

Or did I just not get what you were talking about? :)

[mcsvt]

Thats was my question as well. If you just T into the wg line, the pressure you are giving it has a choice of which way to go, i.e. path of least resistance, which would probably be the manifold.

I think a diagram may help :)

[Frank]

It needs to sit inline with the solenoid keeping the precharged air between it and the wastegate. That way the wastegate thinks there is 12psi on that line and keeps the guage boost down. As you begin to roll out the whole, you release the switch, causing the pressure to fall off into the manifold and you boost begins ramp up slowly since you are building boost and the pressure differential is getting smaller. The size of the canister of precharged air play an important part in how quickly you discharge into the manifold and the wastegate begins to operate normally.

[ottawa rogue]

the air solenoid is the key here, it will allow you to switch between 2 different boost signals to the wastegate can.
after rereading my first post, i see that i misworded my thinking.
it should have said that you could use this source to partially hold the wastegate open, thereby limiting the amount of boost being built at the light.
here's a diagram i drew up, hope it will make things clearer:Dhttp://img.photobucket.com/albums/v699/68torino/boostpreloader.jpg

EDIT... the line running to the manifold should run to the air solenoid also

[ottawa rogue]

It needs to sit inline with the solenoid keeping the precharged air between it and the wastegate. That way the wastegate thinks there is 12psi on that line and keeps the guage boost down. As you begin to roll out the whole, you release the switch, causing the pressure to fall off into the manifold and you boost begins ramp up slowly since you are building boost and the pressure differential is getting smaller. The size of the canister of precharged air play an important part in how quickly you discharge into the manifold and the wastegate begins to operate normally.

That would work also Frank, but like you said it would require a large reservoir
to supply a steady volume of pressurized air

[ottawa rogue]

sorry guys, this is how it should look.
the air solenoid has 2 inlet ports and 1 outlet, basically when powered up, it blocks one port and opens the other.
http://img.photobucket.com/albums/v699/68torino/boostpreloader-1.jpg