Nuts Over Nitrous

Using nitrous oxide to make a car quicker and faster on the street and/or the strip is nothing new to the performance world. Most everyone who has raced at one time or another is more than likely familiar with the basics of how it works and the benefits you can reap from using such a system.

Without getting into detail, we'll just say nitrous oxide is a cryogenic gas composed of nitrogen and oxygen molecules. In automotive applications, nitrous, when injected into the engine, reduces the air temperature, thus producing a more-dense inlet charge. Nitrous oxide increases the oxygen content of the inlet charge and improves the rate at which combustion occurs in the cylinders. Basically, nitrous oxide forces extra pure oxygen into the engine, creating loads of additional horsepower when combined with added fuel. There is a lot more to it, but that is basically how it works.

To give you an example of how powerful nitrous oxide is, we recently installed a 75hp nitrous kit on our project Focus, The Red Hot Chili Pepper. With no other engine modifications, The Pepper went from a 17.001 at 78 mph to an incredible 14.925 at 90 mph. That, my friends, is an insane reduction in e.t. and the install didn't take longer than a day to complete. You can read all about our Focus install on our glorious Web site, www.musclemustangfastfords.com.

We have also installed numerous nitrous kits from a host of different companies on a wide variety of 4.6- and 5-liter Mustangs and have had terrific results with those as well. True, there are other options when trying to pump up the power level of any engine, but buck for hard-working buck, it is still difficult, if not impossible, to match the potential of nitrous oxide for the cost and simplicity factor.

Not long ago, I received a call from a high school classmate who recently purchased a white '98 GT with a five-speed, MAC exhaust system and a MAC cold air kit. The car's owner, Dave Fisher, hopped over to the local racetrack to see what his newfound pony could do and with limited traction, he crossed the traps with a 14.47-second run at 90.15 mph.

Considering the car's factory early 2V status, these times were welcomed by Fisher, but as you may have already guessed, he immediately began brainstorming about ways to decrease the elapsed times of the pony. At first, he entertained the thought of tossing the 2V mill for a more potent 4V powerplant. He even toyed with the idea of replacing the cylinder heads for a trick, ported set, but scrapped those plans when he was informed about the price that comes with them.

It was then that I blurted out the word's nitrous oxide. Dave licked the dryness off his lips and looked into what it would consist of. For an everyday commuter, what could be more practical then nitrous? It will effortlessly dip the Mustang into the 12-second range and, on the street, it can be disarmed and stored for the next track event, keeping the engine stress at a minimum.

Better yet, at approximately $875 (depending on the dealer), it won't break the bank like a supercharger or turbo, and the install can be completed easily with an average amount of experience. After breaking out of our two-man strategic huddle, we began researching what the best nitrous kit might be and found some very interesting choices. Ultimately, we opted for a 150hp dry kit from Nitrous Oxide Systems in Bowling Green, Kentucky. The kit is extremely simple and the mild 4.6 should respond well to it.

Enter the NOS Ford EFI System

"One thing most people are confused with is we rate this kit at 150 hp. That is not a rear-wheel figure, but rather a flywheel figure. The kit, at the wheels, when used with the proper jet (in this case .059), is designed to add approximately 100 more horsepower to the ground. Any more than that and the factory pistons and intake manifold on the two-valve can become a real problem. The kit will generate a solid 150 hp but that is a flywheel figure."

We began the project like most nitrous installs with the solenoids. The two solenoids connect together via a 1/8 NPT fitting and, with the supplied bracket bolted onto the top of them, the next step was to find a good location in which to mount them.

We found some prime real estate for the solenoids on the passenger-side inner fenderwell, near the strut tower. Using a pre-drilled factory hole, we bolted down the solenoid assembly and ran the 3-AN braided line to the MAC cold air tube, which connects the mass airflow sensor to the throttle body.

Before we could tighten the braided line, we first had to drill a hole in the tube (with it off the car) approximately 1 inch before the throttle body opening so we could insert the threaded fitting that holds the nitrous nozzle in position. With the nozzle in place and pointed in the correct direction (the open end must face the throttle body for proper flow), we inserted the .059 jet (4.6 2V, not Cobra) and tightened down the braided line.

We then threaded on the vacuum regulator to the solenoids and routed the (supplied in the kit) rubber line to the original fuel pressure regulator. "The vacuum line on the solenoids gets activated when the nitrous is armed," explained Held. "Its job is to block the fuel that is being returned to the tank, thus boosting the pressure from 45 to 80 psi. This is where the added fuel comes into play--it is not activated through the nozzle with an additional solenoid."

Next came the wiring. The NOS instructions are very detailed and rather easy to understand. After mounting the relay on the driver's-side inner fenderwell, we ran the orange wire (with 15 amp inline fuse) to the positive side of the battery. After connecting one wire from each nitrous solenoid together, we joined them, as per the instructions, to the blue wire on the relay. The two remaining wires on the solenoids then get grounded.

We then searched for a location in which to mount the full throttle switch and found it next to the throttle body. Using a bolt from the throttle cable bracket, we connected the WOT switch to it before hooking up the green trigger wire. The green wire from the relay then routes to one side of the switch while the other side gets grounded to a clean piece of metal on the engine.

When the switch is activated at WOT, the relay is grounded, thus activating the solenoids. During part throttle and at cruising operation, the nitrous, even if it is armed with the cockpit-mounted arming switch, will not activate.

The last wire to be addressed is the red one. It gets routed to the inside of the vehicle and connects to a plastic arming toggle switch we mounted on the dashboard. The other side of the switch gets grounded and a third terminal gets connected to the fuse box, at a key on/engine off source. We found a small hole in a factory grommet (on the firewall), which worked perfectly for our red wire routing into the cockpit.

With the system hooked up and wired, we ran the 4-AN braided nitrous supply line from the solenoid along the frame and into the trunk through a rubber grommet found in the floorboard. With one half of the line in the trunk, we drilled a few holes for the bottle brackets and securely tightened them down, helping keep the bottle rigid and safe on the passenger side of the trunk. All bottles are shipped empty due to shipping regulations and safety concerns, but temporarily, we placed it inside the brackets and tightened it down.

The last step with the NOS transformation consisted of installing the external fuel pump. "The NOS external pump is rated at 67 gph and can be mounted along the underside of the spare tire well, anywhere close to the OEM fuel filter," said Held. After mounting the pump, we disconnected the outlet line from the fuel filter and routed it to the outlet side of the NOS pump with the supplied rubber hose. We then ran a piece of high-pressure fuel line (supplied in the NOS kit) from the outlet side of the fuel filter to the inlet side of the new pump. This will ensure the fuel is filtered before it enters the new external pump assembly.

To activate the pump, we followed the NOS instructions and ran the positive wire from the pump to the brown and pink wire, located in the main fuel pump harness, at the rear of the car, just above the tank. The negative pump terminal then gets grounded to a good, clean metal surface. That's it for the pump wiring; it's simple.

With the system armed and dangerous, we made our way over to Danny's Pro Performance in Keyport, New Jersey, where the nitrous kit would strut its stuff on the dyno. We made a few pulls in before trim (remember, this Stang has a cold air kit and MAC cat-back exhaust) and got 204.8 hp and 276.8 lb-ft of torque--about what we expected.

On the first hit with the squeeze, the white virgin punished the rollers to the tune of 305.9 hp and 369.2 lb-ft of torque. That, my friends, is a solid 101.1 hp improvement (92.4 for torque), proving our initial point that you just can't beat the jug for the money, simplicity, and power potential.

Our next visit was suppose to be over to the racetrack but, due to the wonderful rainy weather here in Central New Jersey, we had to postpone our track time. Rest assured, we will redeem ourselves once the weather breaks. We did, however, hit the gas on the street and, although not recommended by NOS or New Jersey's finest, we found ourselves easing into the full-throttle switch on more than one winding open road.

With a lack of gooey rubber and a generous burnout, the street was no match for our newfound power and high-speed tail slides were almost effortless. [Editors note: Do not try this at home. We are trained professionals.]

Who are we kidding? With all this nitrous onboard, how will you ever be able to hold back? This once 14-second commuter should now be an easy bona-fide 12-second player with traction.

Now, if only that 6-foot blonde knockout from gym class would look me up, though something tells me my wife might not be too thrilled with that.

We then routed the 4-AN braided line from the trunk-mounted bottle to the nitrous solenoid under the hood.	When the bottle gets filled, we'll disconnect this line, crack open the bottle for a split second and flush out any unwanted material such as dirt that might have worked into the line during the install.	The NOS kit also comes with an external fuel pump. The pump is rated at 67 gph, can support up to 700 hp, and when the nitrous is being used, will boost the pressure from 45 to 80 psi creating enough added fuel to prevent a lean condition from occurring.
Using wire supplied in the kit, the positive side of the pump gets tapped into the OEM brown/pink wire that activates the stock in-tank fuel pump.	The negative side of the pump then needs to be grounded on a clean, sturdy piece of metal.	With the nitrous system installed, the next stop was to the all-important chassis dyno to see what kind of rewards we might come up with. Can we make the power that NOS advertises? The dyno will soon tell us.
The NOS instructions are extremely easy to understand and, as long as you follow them word for word, your nitrous system will operate perfectly for a very long time. The orange wire is for the battery positive, the blue wire activates the solenoids, the green wire routes to the WOT switch and the red wire gets connected to the cockpit-mounted arming switch.	Our engine-only pulls revealed 204.8 hp and 276.8 lb-ft of torque. With the supplied .059 jet, we made 305.9 hp and 369.2 lb-ft of torque at approximately 5,400 rpm.	This amount of power should be more than enough to put us in the high-12s on the quarter-mile.
On the dyno, our air/fuel ratio was showing a conservative 11.5 to 1 at 5,400 rpm. This was a safe number and we could have jetted the nitrous system for 20 to 30 additional horsepower but the NOS instructions suggested otherwise due to the factory plastic intake manifold. Although tempted, we left well enough alone and drove the steed home.