Im thinking of doing this when I fit my RRC,
Has any body done this mod to an NA car with standard injectors?
What do you guys think?
DIY Air Assist Valve Delete for Upgraded Injectors
DIY...replace ** Intake Air Bypass Control Thermal Valve with a plug cause it broke - Club RSX Message Board
DIY: Idle Air Assist Valve Delete
Idle Air Assist Delete Kit
All K-series engines
The K-Tuned Idle Air Assist Delete Kit will help clean up the overall look of any K-series engine by removing the ugly and unnecessary Idle Air Assist valve from the engine. This valve is typically mounted on the rad inlet or intake manifold depending on what engine you have. It has a hose running from the top of the valve to the center of the intake manifold and a second hose from the valve to the intake piping. The air assist valve was designed to raise the idle during a cold start up to increase engine warm up speed. Our testing has proved to us that this sensor can be deleted because a properly functioning IACV (Idle Air Control Valve) already does the same job. RSX, TSX, 8TH Gen Civic and EP3 owners will appreciate this delete kit even more because the Air Assist Valve always seems to get in the way when installing an upgraded fuel rail. Included in the delete kit is a plug for the intake manifold port and a plug for the coolant port on the rad inlet or intake manifold."
From what I have read the thermostatic valve is controled by the coolant temp, so when you start the car cold it is open and allow air from the intake to be pulled into the chambers through the injectors to make the fuel slightly leaner as the CAT is still cold and will not filter the unburnt fuel properly.
Although a lot of the forums seem to suggest that it also controls idle speed I believe this to be incorrect and it simply makes the fuel mix slightly leaner whilst the car in running up to temp (Its seems it does partly control idle speed, but when removed the IACV takes over.
The main reasons to delete this seems to be, to make it easier to fit an uprated fuel rail, to improve cold idle when running aftermarket injectors which are not the same length as OEM and do not have the breathing hole, and finally from a cosmetic point of view.
I will be fitting a new fuel rail and I do think It looks a lot better without this valve and hosing, I may be upgrading my injectors in the future too.