Charge Motion Delete Plates
Home | Intake | CMDP | UDP | Exhaust | Suspension | Interior | Aerodynamics | Parts | Dyno | Bolt Ons | Engine | Coyote SwapThe intake manifold features computer-controlled charge motion control valves (CMCV) that are placed in each intake runner path. Below 3250rpm and at low engine loads, ~75% of each intake runner is closed off. This accelerates and tumbles incoming air, homogenizing the air/fuel mixture for improved fuel economy and reduced hydrocarbon emissions especially after a cold start. Above 3250rpm and at higher engine loads, the valves swing wide open as the engine's demand for air increases to provide maximum performance.
The problem is that they present an obstruction to ultimate airflow and therefore rob power. The solution is to remove the original CMCV system from the intake manifold and replace it with a pair of charge motion delete plates (CMDP). The Steeda CMDPs cost $280 but I chose the cheaper option of buying a used CMCV system from another Mustang for a mere $68, and then performed a DIY conversion to custom CMDPs. After they were installed onto my car, I converted my original CMCV system to CMDPs and sold them on for $95, making a handy $27 profit!
When the Mustang GT's Spanish Oak processor is recalibrated with a custom tune that compensates for the revised airflow characteristics of the CMDPs, the result is a 7-10rwhp gain from 3200-6700rpm and a 10-15rwtq gain from 2500-4500rpm. Two more dyno tests showed almost identical peak-to-peak gains of 6rwhp & 9rwtq. Very worthwhile for such an inexpensive upgrade.
CMCVs
The original charge motion control valve (CMCV) assembly. Despite the relatively low mileage of the engine, the internal passages and valves/shafts were coated with thick crusted oil deposits. Nasty!
Oil vapours are scavenged from the crankcase by the vacuum in the intake manifold via the hose and PCV valve from the driver's side valve cover. Over time oil vapours can become deposited on the CMCVs and the intake valves causing them to stick, thus degrading performance.
Degutted
The easy solution is to delete the CMCV system altogether by separating the actuator system, shafts, and valves from the original assembly.
CMDPs
The custom set of DIY charge motion delete plates are bolted back onto the intake manifold, and the engine's ECU reprogrammed with a custom 91 US octane tune uploaded from my SCT X3 handheld tuner courtesy of Brenspeed. The rev limit was also raised to 6500rpm to take advantage of the engine's improved mid-range and higher rpm breathing ability.