Is it possible to crank over the engine using the starter motor without having the car start? I recently installed an aftermarket turbo oil feed line and would like to check if there is oil flow to the turbo before starting the engine. 

Cheers

yes, it's quite simple, you just push the accelerator right to the floor and then crank the engine and it won't start.

Pull the fuse for the fuel pump.

You can remove all the iIgnition coils to remove all spark from the engine. You can also pull fuse for the fuel pump so it doesn't send fuel to the engine.