2003 Dodge Ram - Zex Nitrous System - The Juice Is Loose!

Part One: Mounting The Hardware
First, we carefully chose a mounting location for the Zex NMU that was within reach of the air intake tube. On this truck, the Airaid filter housing served as an excellent location. Mounting the fuel pressure regulator close to the NMU makes for a clean installation, avoiding fuel lines zig-zagging across the engine bay

Install -6 hose ends on bulk lengths of -6 fuel line. Be sure to use steel-braided line for the pressure side and, at a minimum, rubber fuel-injection hose for the return line. Keep in mind, when buying bulk line, the pressure line will need to handle 80 psi, and the return line will be 30 to 40 psi.

Select a location for the purge solenoid close to NMU. Before mounting, check that the supplied -3 line in the Zex purge kit will reach from the tee on the NMU to the purge solenoid. Once you have this verified, install the fittings on the purge solenoid and mount in place with the supplied hardware.

Reinstall the air intake housing back on the base and route the lines down between the firewall and splash shield. Route the lines through the body mounts back to the bed. Be sure to secure the lines with zip ties.

With all of the hardware mounted underhood, start in the bed by mounting the bottle brackets with the supplied hardware. Be sure to verify you have a clear shot under the chosen location, so the lines and the wiring are clear of suspension pieces, and you will be able to access the bolts for tightening. Once the bottle is positioned, drill a 1-inch hole for the nitrous feed line and wiring.

The fuel pump is gravity fed, so it should ideally mount under the bed and still be clear of the moving suspension pieces, the differential, and the spare tire. Install the filter on the inlet side of the pump with the -10 adapter, and fit a -8 to -6 reducer on the outbound side of the filter. Mount the pump with the supplied bolts and insulated brackets; use blue thread-locker on the mounting bolts. Install a -6 hose end on the pressure line coming from the engine compartment, and thread it onto the pump outlet. Be sure to support the fuel line, as needed, to keep it clear of the differential.

Choose a location for the fuel cell, factoring in the routing of the return line, as well as the routing of the supply line to the pump. Also, choose a location that will accommodate easy refilling. To mount the fuel cell, we picked up some bulk aluminum and 3/8-inch bolts, nuts, lock washers, and fender washers. Measure twice and bend once, because the aluminum can only be formed one time without sacrificing its rigidity. Mount the cell in place, and drill a 1-inch hole for the supply line to the pump and return line in the floor of the bed. Double-check under the bed to avoid drilling into suspension pieces or double-walled bed reinforcements.

So we can open and close the bottle on the fly, we're installing Zex's remote bottle opener. Install by removing the manual handle and installing the opener gear. Slide the collar over the bottle, and using the supplied clamp, fasten the bottle opener to the collar. Next, install a single-port -4 bottle manifold to the bottle port, and thread the Auto Meter nitrous pressure sending unit into the manifold.

Use Teflon tape or putty on the NPT thread to avoid leaks.

Ideally, the bottle pressure should be between 900 to 1,050 psi, so to keep our bottle in the sweet spot, we're using Zex's bottle heater with an integral thermostatic control. Affix the heater to the bottle, and fasten the bottle in the insulated brackets.