And here is what I found:
This is how Mitchell On Demand describes them:
IMRC system consists of a remote mounted electric actuator with an attaching cable or linkage to operate the housing butterfly valve plate levers for each housing on each bank. PCM uses a positive change in Throttle Position sensor along with the increase in engine RPM from Crankshaft Position sensor to open butterfly valve plates.
IMRC housing is an aluminum casting with 2 intake air passages for each cylinder. One passage is always open and the other is opened and closed with a butterfly valve plate(s). IMRC housing uses a return spring to hold butterfly valve plate(s) in closed position. Electric actuator houses an internal switch or switches, dependant on application, to provide feedback to PCM indicating butterfly valve plate(s) position.
When engine speed is below 3000 RPM, electric actuator will not be energized, allowing IMRC butterfly valve plate(s) to remain in closed position. When engine speed is about 3000 RPM, electric actuator is energized, causing butterfly valve plate(s) to the open position. Some applications will activate IMRC butterfly valve plate(s) when engine speed is about 1500 RPM.
Intake Manifold Tuning valve is an electric actuator mounted directly to intake manifold. IMT valve operates a shutter device attached to electric actuator shaft. When electric actuator is energized it rotates shaft and opens shutter, allowing both sides of the manifold airflow to blend together.
There is no monitor feedback to PCM from IMT valve to indicate shutter position (open or closed). PCM uses a positive change in Throttle Position sensor along with the increase in engine RPM from Crankshaft Position sensor to open shutter.
When engine speed is below 2600 RPM, electric actuator will not be energized, allowing IMT valve shutter to remain in closed position (no airflow blend occurs). When engine speed is 2600 RPM or more, electric actuator is initially energized at a 100 percent duty cycle, causing shutter to open position (airflow blend occurs). Duty cycle then falls to about 50 percent duty cycle to continue to hold shutter open.
So now the descriptions are out of the way, let's compare:
- IMRC uses positive change in TPS and Crank position sensors to activate
- IMT also uses positive change in both sensors to activate.
- IMRC uses a remotely mounted electric actuator
- IMT uses an electric actuator directly mounted to the intake manifold
- IMRC controls the butterfly valve plates in the secondary intake runners
- IMT uses a shutter to blend airflow between the runners
- IMRC closes below 3,000 RPM
- IMT closes below 2,600 RPM
- IMRC either opens at 1,500 or 3,000 RPM depending on application
- IMT opens at 2,600 RPM
Sunday, January 7th, 2007 AT 6:46 PM