Twincharging works sequentially, the SC will handle initial boost, the Turbo eventually takes over shutting down the SC once the boost pressure in the Turbo Manifold is equal to the total boost pressure (has nothing to do with RPMs). The SC cuts out and gets bypassed when the turbo spools up to maximum boost. The Turbo pretty much blows into the SC. This puts the two Chargers in sync, allowing the quick build-up of boost. When both Chargers together reach maximum set boost, a Bypass Valve is slowly opened around the SC allowing the Turbo to continually increase boost (although manifold is always showing the same boost). When the Turbo alone is pushing maximum boost, the HKS SC Controller, which is monitoring Turbo boost, shuts off the SC clutch and allows the Turbo to take care of all the boosting. HKS has a Twincharger Kit, and you don't even have to worry about Turbo lag anymore neither.
This post has been edited by Jason: Nov 30, 2003 - 11:43 AM