j-spec_cc2

I've been doing some researching on secondary butterflies and i've come to find out that what causes them to open is the engine creating enough vacuum and WOT which pushes on a diaphram which opens the secondaries.
Now, here is my question/theory.

If you are running boost and (for arguments sake) a GE vacuum manifold, would it be possible to run one nipple from the VM to the diaphram? Then, if you are running say 15psi, put a boost solenoid (i think that's what you'd use) inline between the vacuum manifold and the IAB diaphram that would open it at a specified psi? In turn, wouldn't that give you more air above that set psi?

Thanks in advance for any help clarifying this.

AbitAvenger

I thought secondaries were wired in conjuction with the ECU, opening at a rpm the ECU/Tuning program specifies.

Schister66

the secondaries are wired into the ECU and are vaccuum operated. Under the runners on the GSR manifold there is a vac canister that stores vaccuum so once the ECU specifies that the secondaries should open, the vaccuum canister has a release on it which is attached to a diaphragm w/ an actuator arm that opens the valves. It is a simple and effective solution to making torque at low rpm and more hp at high rpm.....i just replaced the whole manifold and started porting the old one....

JonnyCoupe

The vaccuum pipe and actuator function to hold the IAB's closed.

The spring loaded mechanism then holds them open, this is because below 5750 you tend to drive at part throttle and will give you plenty of vac to charge the cannister. At full throttle stuff (no vac) is the only time you will really see +5750rpm, here the springs to hold them open make sense, as you cant run out of springyness.

Just set the IAB's to open as the turbo comes onto song, or maybe at an rpm above your street cruising to help MPG from the faster air speed