This is the car we used to install our propane conversion kit in for testing purposes. Its a stock 2006 Sentra 4 cyl 1.8L.  

The first step to our  installation was to remove the intake manifold. You want to do this so you can properly drill and tap the manifold without getting metal shavings in the intake.

Before you drill the manifold be sure to spend some time making sure you have the inlet nozzles in the correct place. You want these as close to the cylinder head as possible. Its critical to make sure you have them all in the same area.

Once you have the proper locations marked out I recommend using a center punch to mark the holes.

Once the holes are drilled and tapped  you can mount the inlet nozzles.

 Once we had the inlet nozzles mounted and the intake manifold back on the car we mounted the LPG fuel rail.

 Then we mounted the reducer.

The fuel lock off valve was mounted in a place that was easily accessible for maintenance purposes.

Then we mounted the MAP sensors and ran the necessary vacuum lines

 We then ran some soft copper tubing from the fuel lock off valve under the car and into the trunk. And set it up to use a fork truck tank temporarily.

 We used a tank that was readily available. Using a fork truck style tank is very common and the cheapest way to go.

Time to mount the switch and we are done with the installation and on to the calibration.

Go grab the laptop its time to configure the propane ECU.

 After a quick auto calibration its now time to drive it around on gasoline then propane and create the map.

Once the software is fully configured the installation is complete. Now you can drive around on propane and feel good about yourself because you are doing your part to save the environment!