How to Hide Nitrous Oxide

BEFORE
AFTER

We used an NOS Under-Manifold Cheater System (PN 02620) that included direct-port nitrous nozzles, tubing, fittings, a distribution block, nitrous and fuel solenoids, braided stainless steel lines, activation switches, mounting brackets, a filled 10-pound nitrous bottle, and instructions. The kit is factory-set at 150 extra hp, but it can be adjusted to deliver between 100 and 250 hp.
We used an NOS Under-Manifold Cheater System (PN 02620) that included direct-port nitrous
To perform the installation, you’ll need basic items such as a drill, a 1/2-inch end wrench, a tubing bender, a tubing cutter, thread-sealer compound, a marking pen, and patience.
To perform the installation, you’ll need basic items such as a drill, a 1/2-inch end

We installed our NOS under-manifold nitrous system on an Edelbrock Performer RPM aluminum intake manifold (PN 7101). Not only does this intake provide outstanding power output, but it also looks fairly stock, adding to the sleeper image of a car. Usually, dual-plane manifolds are easier to plumb because the underside of the intake runners (the area where the nozzles will be located) doesn’t sit flush with the edge of the port, as is common with many single-plenum manifolds.
We installed our NOS under-manifold nitrous system on an Edelbrock Performer RPM aluminum
Begin by flipping the intake manifold over so that the lifter-valley side is showing, then use a felt-tip pen to mark the nozzle locations. The nozzles should be equally centered within the base of the intake port and 5/8 inch apart from each other. Remember, each port gets one nozzle for nitrous and one for fuel.
Begin by flipping the intake manifold over so that the lifter-valley side is showing, then

Transfer the markings from Step 4 to the underside of the intake runners. Then make a horizontal marking across each line about 1/4 inch from the edge of the intake-gasket flange. Afterward, use a hammer and a punch to mark the locations to drill holes for the nozzles. Make sure the nozzles are installed so that they don’t hit anything when the manifold is installed.
Transfer the markings from Step 4 to the underside of the intake runners. Then make a hori
Drill a 1/4-inch hole at each of the eight marked locations of the intake ports. The holes should be drilled so that the nozzles will slightly face toward each other when installed.
Drill a 1/4-inch hole at each of the eight marked locations of the intake ports. The holes

Use a 1/16-inch NPT tap to cut threads in each of the 1/4-inch holes. Afterward, carefully remove any debris, metal shavings, or sharp edges.
Use a 1/16-inch NPT tap to cut threads in each of the 1/4-inch holes. Afterward, carefully
Apply some thread sealant (not Teflon tape) to the threads of the small nozzles. Then thread in and tighten the nozzles. The small openings in the two nozzles should face slightly toward each other so that when the nitrous system is activated, the nitrous and fuel are sprayed into the center of the intake port on the head. For plumbing purposes, with the base of the manifold facing up, install the nozzles in the following order (beginning at the rearend moving forward): nitrous, fuel; nitrous, fuel; fuel, nitrous; fuel, nitrous.
Apply some thread sealant (not Teflon tape) to the threads of the small nozzles. Then thre

After nozzle installation, this is how our setup looked. Notice how the nozzle openings face slightly toward each other.
After nozzle installation, this is how our setup looked. Notice how the nozzle openings fa
Center the distribution block on the underside of the intake manifold. Usually the block will sit directly on the outside of the heat-riser passageway. The bottom row of fittings on the block will be used for nitrous, and the top row will be used for fuel. Begin by installing the nitrous lines, starting first with the closest (shortest and hardest to bend) line. Thread on the first steel tube and tighten it finger-tight.
Center the distribution block on the underside of the intake manifold. Usually the block w

We inserted a short piece of tubing into the distribution block to serve as a template showing the level at which the to-be-bent line needs to be. In the area just past the ferrule nut, the line was bent downward until it intersected the template tubing. Afterward, a pen was used to mark where the tube needed to be bent to go to the distribution block. The lines should be bent so that they tuck up near the base of the intake to prevent any line-to-block interference when the manifold is installed.
We inserted a short piece of tubing into the distribution block to serve as a template sho
Apply a small amount of thread sealer to the 16 compression fittings and carefully tighten them into the distribution block.
Apply a small amount of thread sealer to the 16 compression fittings and carefully tighten

Using a tubing bender, carefully form the steel tubing so it matches the proper bend locations as indicated by the pen mark(s).
Using a tubing bender, carefully form the steel tubing so it matches the proper bend locat
Position the newly bent line to check the accuracy of your work. If all is correct, mark the steel line in the position where it intersects the end of the fitting on the distribution block. Then measure 3/16-inch longer and make a second mark with the pen.
Position the newly bent line to check the accuracy of your work. If all is correct, mark t

Use a tubing cutter to cut the steel line at the location of the second pen mark. Afterward, deburr the end of the tubing, if needed.
Use a tubing cutter to cut the steel line at the location of the second pen mark. Afterwar
Install a compression nut onto the tubing end, followed by a ferrule. Then properly position the tube and tighten the factory-installed nut onto the nitrous nozzle. Afterward, tighten the new compression nut and ferrule combo onto the proper fitting on the distribution block. As you tighten, the ferrule will be automatically crimped onto the steel tube.
Install a compression nut onto the tubing end, followed by a ferrule. Then properly positi

After the first nitrous line is installed, make the next one (this second line should be the next closest line). You want to install the shortest lines first because they are more difficult to bend and properly position. As the lines get longer (for farther-away ports), the plumbing gets easier. Here, another nitrous line is being marked prior to being bent.
After the first nitrous line is installed, make the next one (this second line should be t
After you’ve installed the eight nitrous lines to the lower portion of the distribution block, carefully check your work to make sure the fit is proper. It should look as shown in the photo. If all is correct with the nitrous lines, begin bending and installing the fuel lines.
After you’ve installed the eight nitrous lines to the lower portion of the distributi

The fuel lines should come off the top row of compression fittings on the distribution block. Once again, begin making the fuel lines starting with the nozzle that is closest to the distribution block. This line will be the shortest and most tricky line to make. Here, the first fuel line has been made and is ready to be threaded on.
The fuel lines should come off the top row of compression fittings on the distribution blo
Continue bending each fuel line (working from the next shortest and finishing with the longest) and then tighten it to the proper position. After the last line is fitted, inspect each line and give each compression nut a final tightening.
Continue bending each fuel line (working from the next shortest and finishing with the lon

Apply some thread sealer to the two 90-degree fittings and then thread them into the sides of the distribution block. Afterward, thread on and tighten the two short runs of braided stainless steel hose (one hose per side). The hoses will run to the nitrous and fuel solenoids that are hidden where they will be least noticed.
Apply some thread sealer to the two 90-degree fittings and then thread them into the sides
There are two common ways to secretly mount the nitrous solenoids. Our favorite entails drilling two holes in the back of the cylinder block, installing the special NOS-supplied fittings, and mounting the solenoids near the back of the block. You can also drill two holes in the rear of the intake manifold and have the solenoids mounted somewhere near the firewall. However, when the lines exit the intake, a savvy car crafter might spot the nitrous system.
There are two common ways to secretly mount the nitrous solenoids. Our favorite entails dr

We’ve been told that if you mount the nitrous and fuel solenoids about 1 or 2 feet from the rear of the engine, the added distance slows the nitrous hit, making it come on less violently. For a street sleeper, this soft hit may actually be beneficial because it won’t wildly spin the rear tires. Here, this street sleeper has solenoids mounted out-of-sight under the dash.
We’ve been told that if you mount the nitrous and fuel solenoids about 1 or 2 feet fr
Mount your activation switch on a cord hidden in the ashtray. Let everybody check out your car, and when it comes time to use nitrous, simply open the ashtray and pull out the switch.
Mount your activation switch on a cord hidden in the ashtray. Let everybody check out your

Our favorite way to activate a nitrous system involves using the horn button. Unplug the horn(s) and plug your nitrous solenoid activation wires into the horn relay. The nitrous system will be in the off position until the horn relay is activated (by way of pressing the horn button). CC
Our favorite way to activate a nitrous system involves using the horn button. Unplug the h

Because nitrous oxide is known for creating big power increases, it’s the first item many people look for on a sleeper. If it’s discovered that you’re running squeeze, oftentimes the race will be called off. Thus, the trick to building a successful street sleeper involves fitting your car with nitrous--but doing it so no one can tell.

This story focuses on two ways to install a hidden nitrous system--an under-manifold system and a plate-style system--and it supplies additional nitrous tips. But because nitrous delivers such a forceful horsepower hit, be sure to upgrade your chassis and drivetrain components. Otherwise, your potent powerplant might puke your other components. (Nice alliteration, eh?)