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Charge Motion Control Valves and Removing Them On the 05-08 Mustang GT

Written By: Dylan Abbott

Shop 05-09 Mustang Intake Parts

Making your Mustang breathe is the key to making power. Along with fuel, intake air is one of the single most important variables in combustion. Upgrading your Mustang's intake system is one of the more simpler engine mods you can make and a great starting place for beginners.

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Charge motion control valves (CMCV), also known as Intake Manifold Runner Control (IMRC) have been on certain models of Mustangs for almost 20 years now. IMRC was introduced in the mid-90’s on the 4V Cobra engines boosting low-end torque and improving fuel economy. IMRC was later used on some Ford V6 engines as well. They were never offered on the 2V GT engines but were included with the 4.6L 3V engine beginning in 2005. The plates that housed the IMRC on 05-08 Mustangs were removable from the intake manifold, but in 2009 Ford began completely integrating the valves into the intake manifold.

How Do CMCV and IMRC Work?

CMCV are integral to the intake manifold and work by blocking a portion of the intake port, restricting airflow and increasing air velocity. This reduction in airflow reduces the fuel requirement for the engine, increasing fuel economy. CMCV can provide more stable idle characteristics. The CMCV are computer controlled and when the air demands of the engine are increased, such as at wide open throttle or at high RPM, the PCM opens the valves. The valves are flat plates mounted on a shaft that runs lengthwise through both intake banks. When the PCM sends a signal to the CMCV or IMRC motor, it rotates the shaft in the intake manifold, which opens the butterfly valves. With the valves now open, the engine will breathe freely and produce more power at high RPM.

Pros and Cons to Charge Motion Control Valves

For a stock engine, the performance benefits of the IMRC outweigh the disadvantages that they bring to the table. For the majority of Mustang owners that will never mod their cars, the IMRC offer great low-end torque and help to maintain fuel economy. The only issues these owners may run into is a sticky or stuck valve, necessitating the replacement or repair of the CMCV system.

IMRC becomes a hindrance on modified engines, especially boosted engines. In the fully open position, the valves are still a slight restriction in the intake manifold, robbing you of a 5-10 horsepower and torque when naturally aspirated. Mixing charge motion control valves and boost can be a recipe for disaster. The excess pressure and airflow trying to force past the valves can cause them to break. If you are unlucky enough for the plates to break and they make their way past the intake valves, you can seriously destroy or damage your engine. Without a catch can or oil separator installed on your Mustang,  sludge will build up over time on the valves and they will begin to stick open or closed. Valves that are stuck in the closed position with dramatically reduce engine output until they are repaired.

Are Charge Motion Delete Plates a Good Mod for Me?

Charge Motion Delete Plates (CMDP) are machined plates that replace the factory charge motion control valves. They do not have any butterfly valves in them and completely eliminate the restriction caused by the stock CMCV. They are also port matched to the intake manifold and cylinder head, giving you the most power possible with the stock intake manifold. If you have already installed or are planning to install a set of aftermarket camshafts in your Mustang, then a set of charge motion delete plates will complement them perfectly, ensuring your engine can inhale all the air it needs. 

Installing CMDP should be a top priority for anyone that has a centrifugal supercharger or turbo kit with a stock intake manifold. As previously mentioned, the butterfly valves can break under boost and cause serious engine damage. Positive displacement superchargers do not reuse the factory intake manifold, so CMDP are not required and will not work with them. 

Anyone that deletes the CMVC from their Mustang will require a tune update. Without disabling the CMCV parameters in the PCM and making adjustments for airflow, your Mustang may run poorly and make less power than it should. Proper calibration is essential to getting the most benefit from your CMDP. If you have an 09-10 Mustang you will need to also purchase an 05-08 stock intake manifold to install CMDP. The integrated valves are not removable on the 09-10 intake manifold.

All Charged Up

CMCV deletes are an inexpensive and effective way to increase your 3-valve Mustangs power and reliability. You no longer have to worry about old, sticky valves robbing your Mustang of horsepower and torque. CMDPs will have your Mustang taking full advantage of it’s intake system and maximizing the power output of an engine with a stock intake manifold.