A scavenge pump is a pump that you use to pull the oil out of your turbo. That is one of the most important parts of having a long living turbo. Alot of kits just use gravity to get the oil back into the pan and they tell you oh it will be fine. Well it wont hahah,,, it will leak past the seals get into the compressor housing and make a mess. It will also get into the turbine housing and smoke. I think there was a member on here that had oil coming out of his compressor housing and thats why. There is alot to be said about over oiling turbos as well. Just ask alot of questions when you decide to take the plunge. I built my kit and I know guys that have been playing with turbos since before alot of us were born, so I get alot of good what to do and not to dos.