The best way to tell if the Cyclone is working or not is to tee your boost gauge into the line to the Cyclone diaphragm. You should see vacuum there until 4100+ rpm, at which point it should drop to zero, atmosphere.
In order of preference, as far as how to hook up the Cyclone, I think I would rate them:
1) Triggered by RPM, using the ECU or a "pill", as suggested above.
Since the runners of the Cyclone are tuned for different rpm bands, this seems to give the best of both worlds, with a smooth transition when they switch. Best when uses with a vacuum canister, which will hold the secondaries shut until the rpm trigger point has been reached, even though there is no longer vacuum in the intake.
2) Activated by boost. This was the old way, where we used to use a Hobbs switch, set to a certain boost pressure at which point the vacuum in the diaphragm is allowed to escape to atmosphere. Best when uses with a vacuum canister, which will hold the secondaries shut until the right boost pressure.
3) Many people simply connect the Cyclone diaphragm directly to the intake port, so the secondaries will open as soon as there is no more vacuum to hold them shut. The 2 bad parts of this are that this usually activates the secondaries too soon, so you lose much of the lowend torque benefit, and you are also exposing the diaphragm to very high boost pressures, which could cause premature failure. As far as I know, parts to repair or replace the diaphragm are no longer available.
4) You *can* just leave the vacuum line to the diaphragm disconnected, but the manifoild will basically act just like a standard USDM intake manifold at that point, so you aren't benefitting from any of the advantages of the Cyclone.
