Giving our LML an extra kick

In the pursuit of more power, truck owners have several options. The most common modifications to increase a truck’s power include adding a turbo or two, upgrading the intake and exhaust, and adding more efficient and effective fuel pumps and injectors. However, all of these modifications only increase the power of the truck while it still runs diesel fuel. Another option exists that adds incredible power and punch to any vehicle—regardless of the engine type—and that is to install a Nitrous Oxide System, or NOS.

NOS increases the performance of the engine through the introduction and subsequent breakdown of nitrous oxide. When introduced into the combustion chamber, nitrous oxide splits into the individual molecules of nitrous and oxygen starting at about 570 degrees Fahrenheit. With the increased oxygen available during combustion, more fuel can be injected, which yields greater horsepower.

Additional benefits of NOS is that it not only increases performance of the engine, but when it vaporizes, the nitrous oxide noticeably cools the intake air. Cold air is naturally denser than warm and hot air because of reduced Brownian movement and the lack of excited molecules.

With that in mind, installing a NOS kit on any diesel is worth considering if a sudden kick of power is desired.  Before installing the kit though, double check the different regulations of your state, and review any warranty information to ensure that after the install the truck will not attract any undue or unwanted attention, or have a negative impact on the overall price and the cost to repair the vehicle.

The following is a step-by-step, dry push-button Nitrous Express Diesel Nitrous System kit that was installed by Custom Auto in Idaho Falls, Idaho, on a 2011 Duramax LML. Keep in mind that different makes and models of diesels will require slightly different installation procedures.

Begin by blocking out where the NOS kit tank will sit in the truck bed, which in this ‘11 Duramax LML was close to the passenger side of the cab after accounting for the nozzle head and where the NOS fuel line would be routed. Once the blocking is complete, drill a hole through the truck bed wide enough to fit the 6AN stainless steel threaded fuel line. Next mount and bolt the bracket to secure the NOS tank clamp to the truck bed.

Secure the nitrous fuel line to the undercarriage of the truck, following the wheel wells, ensuring a snug, tight fit. Find an entrance through the case of the engine compartment, or carefully drill an opening to connect the wheel well and the engine compartment through which the NOS fuel line will pass.

To regulate and direct the nitrous, mount two Vibrant vacuum distribution blocks to both the driver and the passenger sides of the engine compartment. The two different vacuum distribution blocks will add two different quantities of nitrous to the engine to create the desired increase in power. When complete, the passenger-side distribution block will add an increased 150hp, and the driver-side distribution block will add 250hp. Connect the 6AN threaded fuel line from the NOS tank to a T-fitting. Thread the T-fitting into the bottom of the Vibrant distribution block.

Seal the left side of the Vibrant block to prevent any nitrous leaks, and connect a Lightening Nitrous Solenoid Stage 6, with a .093 orifice, to the right of the distribution block. Once the 150hp nitrous solenoid is connected to a Stinger power distributor, the solenoid will control the flow and quantity of the nitrous into the turbo inlet to increase spooling.

Attach the 250hp nitrous solenoid to the bottom of the driver-side Vibrant vacuum distribution block.

To the right of the T-fitting, connect another 6AN stainless steel braided fuel line for the remaining nitrous to flow into an NX Lightning 250 Nitrous Solenoid with a .250 orifice. Running the fuel tube along the top of the back of the engine compartment, carefully secure the NOS fuel line. Connecting to the 250hp distribution block, the nitrous solenoid injects the gas directly into the intercooler pipe.

With this dual configuration, 150hp of nitrous is injected into the turbo to increase the spool speed, and an additional 250hp of nitrous is injected directly into the intercooler pipe for maximum performance and power.

To power the 250hp nitrous solenoid, mount a Stinger SPD514 power distribution to the side of the engine compartment. The power distributor will be connected to another Stinger electric solenoid.

After securing the power distributor, attach the power distributor to an electric solenoid.

Disconnect both batteries before wiring, and attach the solenoid to the battery. This will control the 250hp solenoid when injecting the nitrous. Repeat this process for the 150hp solenoid on the other side of the engine compartment.

Next, prepare the intercooler pipe by welding the weld nuts needed for the dry nozzles that will inject the nitrous into the engine through the intercooler pipe. This is a dry NOS kit, meaning that the nitrous is injected without a fuel, or wet mixture. 

Thread the dry nozzles into the intercooler pipe.

Repeat the process for up to two weld nuts welded into the intercooler pipe. Ensure that the dry nozzles are facing toward the direction of the airflow. 

To determine the direction of the dry nozzle, position the NX logo toward the direction of the airflow. The other two weld nuts will be used for the turbo wastegate and the boost pressure gauge.

Attaching the appropriate AN thread to the dry nozzles, thread the braided wire from the intercooler pipe to the nitrous solenoid. Route the nitrous to the appropriate dry nozzle using pure flow Y.

To activate the NOS, push the button when the turbo begins to light. It is recommended to only hold the button for two-second intervals. Generally, a shot of nitrous will increase the horsepower by 1.5 times.