John Hedenberg
June 16, 2003
Contributers: John Hedenburg

Step By Step

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Although not comparable to a 5-liter V-8 or Modular power, the 2-liter 16-valve ZETEC mill in the ZX5 did blast to a 16.90 at 79.99 mph with nothing more than a Steeda cold-air kit and a Focus Central 65mm anodized red throttle body. At only 100 hp to the front wheels, it's very obvious that "The Pepper" can surely be improved.
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For the nitrous kit, we went to the pros at Nitrous Express in Wichita Falls, Texas. They sent us an adjustable Stage 1 kit that can be tailored from 35 to 75 hp and uses fuel as well as nitrous to deliver loads of extra ponies. The kit works with the factory fuel pump and computer and requires (at 75 hp) no timing retard devices.
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We began by removing our Steeda cold-air pipe so a 9/16-inch hole could be drilled in it to mount the NX Shark nitrous/fuel nozzle. After drilling the hole, we installed the supplied fitting and threaded the nozzle into it.
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Make sure when tightening down the nozzle, it faces the right direction. The open end of the nozzle must be directed towards the throttle body opening and NX recommends locating it 2 to 6 inches from the throttle body for optimum performance.
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We found a convenient location to mount the solenoids...
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...right on an engine bracket by the front of the cylinder head.
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Next, you will need to ground one wire from each solenoid to the chassis or engine. We routed the two wires to the same engine bracket that houses the solenoids. Because they are of a direct current design, it doesn't matter which wire you ground and which one you activate with battery power.
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Danny Ryder of Danny's Pro Performance in Keyport, New Jersey, was nice enough to fill our empty 10-pound bottle with the good stuff. All nitrous companies ship their nitrous systems with empty bottles for safety reasons and shipping regulations. Most speed shops will have nitrous filling stations on hand and will charge between $30 and $40 to fill a bottle. It is also a good idea to find out if the filling station you are using has a filter on it. This will ensure your nitrous is clean going into your new bottle.
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We found a convenient location to mount our bottle brackets in the hatch area, on the passenger side.
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After drilling four holes in the floor, we tightened down the brackets (with the supplied 3/8 bolts) and placed the bottle inside of them with the nitrous line fitting facing downward. This will ensure that the siphon tube is in its best location.
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The braided nitrous line on the bottle can then get routed to the solenoid under the hood.
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We found an extremely handy factory grommet under the driver's side rear seat that worked perfectly for the routing of our nitrous line.

I have a confession to make. After years of being in denial and carrying around the fear that goes along with nitrous oxide usage, I have to admit that I have officially graduated to nitrous junkie status! As mentioned in our past two Focus stories, we had (and still do have) plans to install a turbo kit from Precision Turbo, but as the testing on that piece continues, we elected to make up some lost time with a little bit of laughing gas.

Since this would be my first experience with the jug as far as my personal car goes, I was a little nervous and had a ton to learn about the proper dos and don'ts when using the force-fed additive. With a best time prior to the nitrous install of 16.907 at 79.99 mph, we were happy and surprised our factory automatic Focus ZX5 could run that quick, but like all gearheads we wanted much more--enter nitrous oxide.

After trying for months to weasel my way out of it, the big guy across the hall, Editor Jim Campisano, laid down the law and scheduled a nitrous install on The Red Hot Chili Pepper. No doubt our 16.90 e.t. would be lowered dramatically with the spray, but I knew nothing about nitrous usage. Regardless, I took off my skirt and panties and began researching different nitrous kits for the Focus. One company that offers a dynamite setup is Nitrous Express in Wichita Falls, Texas. They had been around the game for decades and know the beast inside and out.

NX Marketing Manager Randell Mathis and I struck up a conversation and he recommended we install its NX Stage 1 kit onto our Infra-Red five-door. The Stage 1 kit works with the factory fuel system and computer and does not require a timing retard feature to be used. This cut down the cost and sophistication factor for sure, as well as simplifying the installation process.

Before we begin, let's first explain how nitrous oxide works, how it generates additional power and why some racers (myself included) are a little intimidated by it. "There is no reason to fear nitrous use," explained Mathis. "The main reason why people are afraid of the stuff is because they don't use it properly, engine damage results, and the nitrous is the easiest item to blame. The truth is if used correctly, nitrous oxide is just as safe as a supercharger or turbo kit.

"Nitrous consists of one part oxygen and two parts nitrogen. When injected into the engine, nitrous turns into pure oxygen when it reaches 563-degrees Fahrenheit. The nitrous gets heated when it becomes injected into the cylinders of the engine by heat from the combustion chambers and, when mixed with extra fuel, will generate loads of extra power."

We then asked Mathis why a wet system (nitrous and fuel) is preferred over a dry system (nitrous only) and he said that a wet system doesn't require the computer to be re-calibrated because it [the nitrous] gets injected after the mass airflow sensor.

"By using a dry system, you will have to locate the nozzle before the mass air sensor and after the sensor picks up on the additional oxygen (nitrous) it will have to re-calibrate the entire system in order to compensate the nitrous with extra fuel," he said. "It's much easier to just add the extra fuel right at the nozzle with a fuel solenoid. Also, in back-to-back testing, we have found that a wet system will generate much more torque when compared to a dry kit. Our kits can add over 50 lb-ft of torque more than a similar dry system. Injecting the nitrous and fuel right at the nozzle is the main reason why a wet system works so well."

Installing The Stage 1 Kit
We began by removing our Steeda cold air tube so we could drill the appropriate hole in it to mount the nitrous nozzle, known by NX as the Shark nozzle. It attaches to the tube with a threaded fitting that protrudes through the 9/16-inch hole in the tube you just drilled. The NX instructions indicate that, for optimum performance and atomization, it should be mounted between 2 and 6 inches from the throttle body.

"Our Shark nozzle has what we refer to as a Bath Tub tip on it," said Mathis. "The tip injects the fuel in front of the nitrous for a much better atomization between the two. The design on the tip of the Shark nozzle creates a swirling, vortex-type pattern of nitrous and fuel, equaling more power." With the nozzle in place, we re-installed the aluminum inlet tube and began searching for a good location in which to mount the two solenoids. You wanted to keep them away from heat and moisture and the best location we came up with was on the driver's side of the engine, on a bracket that is connected to the cylinder head (used for removing the engine). With the solenoids attached to the steel bracket, we grounded one wire from each solenoid and attached the braided lines from them (with jets) to the Shark nozzle.

Next we attached the relay to the driver's side strut tower and connected the four wires to the proper locations as per the NX instruction sheet. "The green wire gets routed to the solenoids (to activate them), the white wire goes to ground, the black wire is your constant (battery) power source and the red wire is for your activation switch," explained Mathis. "It is really simple and should be done exactly as the instruction diagram shows."

The next step was to bolt the bottle brackets in the hatch area and mount the 10-pound nitrous bottle. After drilling four holes in the floor, we tightened the bolts and placed the bottle inside them.

"It is important to angle the braided nitrous line fitting in the downward position in order for the siphon tube [in the bottle] to operate at its best," Mathis recommended. "Otherwise, you might not have the proper amount of nitrous flow [to the tube in the bottle] and the true potential of the kit will not be experienced.

"As far as filling the bottle goes, a good rule of thumb is that for every 10-seconds of nitrous use (with a 50-horse jet) you will use approximately .4-pounds of nitrous. Usually, you can get between 10 and 12 runs before needing to fill the bottle at this level. At optimum temperature (1,000 psi) it should last for quite a bit of runs."

From there, we had to route the 4-AN nitrous line from the bottle to the nitrous solenoid, located under the hood. To our good fortune, there was a rubber grommet under the rear seat, located on the floor that was just perfect for our line routing. We made a minute slit in the rubber, fed the nitrous line through it and routed it up the side of the frame where it was connected to the bottom of the nitrous solenoid.

"It is wise to flush out the nitrous line prior to connecting it to the solenoid," explained Mathis. "You can do this with compressed air and it is extremely important to rid the line of any debris it might have in it. The inlet port of the solenoid does have a filter (screen) in it, but it can become clogged with debris and hurt flow."

Did It Work? Did It Eever!
At Old Bridge Township Raceway Park, I first made a non-nitrous pass to establish a baseline and on this day she topped out at 17.001 seconds at 79.59 mph. We then backed up that run with a 17.05 at the same speed. The 60-foot times were nothing to brag about either. Our best was a yawn-inducing 2.43. With the kit armed and ready, we hit the ignition key, checked to verify the solenoids were operational (they must both click when the button is depressed) and made a path toward the starting pad. With the bottle cracked open and my right thumb hovering over the arming button, I power-braked the engine at 2,500 rpm and let it rip when the light turned green. On the first run, I still had some trepidation and was way too conservative with the button. Still, on the first nitrous pass, I bettered our 17.00 at 79.59 mph with a staggering 15.469 at 90.76 mph (2.40 60-foot). While this was impressive, I was way too cautious with the button and knew that something better--a lot better--was in the cards. After a lengthy cool down I made my way to the line for the second attempt.

Squirting the car out of the hole dropped our 60-foot time to 2.22 and at the stripe the scoreboard displayed a mind-bending (for this car) 14.925 at 89.66 mph--and this was only with the 75-shot jetting. That's a solid 2.076-second improvement and is not a bad way to spend a mere $629. Imagine what we could have done with a 100-shot. Mathis explained to us that the factory fuel pump would never keep up with more than a 75-horse jet and he doesn't recommend using more than the 75 pill, but you can run 100-horse jets with the proper fuel system in place.

One thing we did notice was with the jug on, the transaxle dropped from 7,000 rpm to 3,000 between shift points and took, I don't know, about five minutes to decide what gear it wanted to go into. For Focus owners who plan on using nitrous or a turbo, a quality transaxle overhaul (and aftermarket converter) should be in the cards. The OE trans is simply not designed to handle the extra load of a power adder and will wind up failing over time. We are now in love with our newfound power and, after installing our turbo kit, we might even kick down the jetting in the nitrous and try using both of them together. Think about it for a minute, a heat-generating turbocharger with a small shot of nitrous on top of it. Can someone say warranty claim?