Originally Posted by
Vas
I personally would not disconnect the DISA valve. Reason being is that the DISA valve is what lets the intake manifold use both set of internal runners.
Below the activation point of 4k rpm, the shorter runners are used to push the air into the engine in the lower rpm range. When the DISA valves activates, the longer runners then are being used. The way I see it is that if you disconnect the DISA valve, the intake manifold will always be using the longer runners which in theory would result in a torque/power loss in the lower rpm range. Up top the car would feel the same.