The Dukes does not require a vacuum pump to work properly.  The only purpose of the vacuum port is to dump pressure on takeoff to avoid the ear pop inside the cabin.  If this pop doesn't bother you, then no need for a vacuum pump.  If it does, it can easily be accomplished with a switch that grounds pin 4 on the Dukes head and turns on a small vacuum pump to pull the bellows open.  Just make sure you turn it off before getting too high to avoid a sudden pressurization.  I have mine set up with a VP 200 such that it automatically turns on when in takeoff mode and turns off when the VP200 switches to cruise mode.  Has worked flawlessly for 600 hours.

Here is the pump I use:

https://www.sparkfun.com/    $14.95 - ROB-10398 - Vacuum Pump - 12V  

Pete


-----Original Message-----
From: k T [mailto:ktad9@hotmail.com]
Sent: Wednesday, October 09, 2013 6:46 AM
To: lml@lancaironline.net
Subject: Removing vacuum pump?



Hello Dico,
You will need a vacuum port to the Dukes pressure valve for the pressurization to work correctly, I do not have any gyro instruments either but I needed to install an electric vacuum pump near the Dukes valve

Kamal T

N1104T