Question about SCT IMRC function
I have a 2005 XZ4 D2.0 MTX75 and SCT Pro Racer package
According to SCT tuning manual, IMRC is the device that changes from long/short runners. The D2.0 does not have this device, it has single runners. The D2.0 only has tumble flaps(flap that opens/closes right in front of intake port where the manifold bolts to head). The D2.3 has both.
Problem: The tumble flaps on my D2.0 appear to be controlled by the IMRC function in the SCT software. This function is using IMRC tables to modify spark. According to SCT tuning manual, the spark is modified because of the change in runner length. But, as stated before, the D2.0 does not have dual runners.
-Why is spark being modified for D2.0 when it does not have dual runners?
-How are the tumble flaps and dual runners controlled on the 2.3?
-Are they both controlled by the same IMRC function I see in the 2.0 tune?
-Are they controlled separately? If so, what function controls the other one?