I just acquired my 04 R53 MC40S with 64k miles. The previous owner had an electric water pump installed. I would like to autocross this car occasionally, so I am considering putting an oem water pump on it to avoid the classing bump caused by the ewp. Has anyone done this swap, or can anyone who's done the ewp conversion tell me what I need to order in addition to the water pump to return to stock?

Sorry this is my first post without a proper introduction, but I'm trying to place an order today.

 

The factory water pump is driven off the backside of the supercharger. Sometimes the gears go bad and cause a failure. If this is the reason it was changed to electric you're going the need to rebuild the SC.

 

Good point. I don't think that was the reason, but is there a good way for me to check condition of the gears without a full disassembly? Should I be able to reach in with a boroscope and look around?

 

You would need to remove the PTO cover that covers the gears. Its pretty crowded there and it depends how the po installed the ewp. A boroscope wont work. If you still decide to go back oem style waterpump, I'll buy your ewp setup.