derSchwamm

iTrader: (1)

Since this thread has already been revived, can I ask for more details on how you drove S5 aux ports using exhaust backpressure? My understanding is that unlike S3 and S4 aux ports, S5 ports need the air pump to pull the ports open. I have a full S5 swap on my FB but would love to remove the air pump since it's otherwise worthless

mjm4jc

I am currently using the stock air pump to feed both the VDI and aux ports. My Haltech controls the triggered rpm for the VDI. My rpm switch controls the trigger for the aux ports. I strongly recommend using your factory air pump. There's no better way to work the vdi and aux ports The S3 aux ports will bolt up to the S5 LIM no problem. There's little modifucatiom. Then you can use exhaust BP for the aux, if you want to go that route..But you still need a pump for the VDI, and the stock air pump is best IMO.

In the future, I am going to start pumping fresh air into the exhaust from the air pump to dilute the strong exhaust fumes. I currently have no emissions components.

BTW..... The drag of an air pump is probably immeasureable.

RX7_Renesis

iTrader: (1)

The drag of a properly working air pump is probably immeasurable.

The drag of a seized air pump is unmeasurable .. as in it will not budge no matter how hard I try.




I would gladly trade off the extra weight and parasitic drag of an air pump in exchange for properly working VDI and auxiliary ports.

LongDuck

You can disassemble the Air Pump and you'll find there are 3 metal vanes and one of yours has become dislodged and jammed somewhere in the scroll mechanism. The basic operation is that an offset shaft rotates around a fixed plenum which results in compression of air against these 3 fin vanes inside. They're remarkably similar in size and shape to Apex Seals, and you may find that the one which became dislodged is located in the rubber tube leading to the Air Control Valve. Imagine my disbelief when I found what appeared to be an Apex Seal in there,...

I removed the one bad vane, and rebuilt and regreased the remaining mechanism, and it's passed emissions testing on multiple occasions! Apparently, you don't need a lot of airflow to work properly, as it's only operating at 66% efficiency for air movement. Regardless - don't throw away your Air Pump!