Cheap and fast aren't usually synonymous, and plans for big-horsepower street machines are often confined to our daydreams. But there are exceptions, and one of them is called nitrous oxide.
Due to the low entry-level costs and relatively easy installation, nitrous kits are more popular than ever, and they offer the advantage of horsepower on demand without compromising the streetability of a car that may be your daily driver. With that said, nitrous kits for fuel-injected cars like our 5.0L '89 Mustang GT are generally more complicated and expensive than typical plate systems that fit under a carburetor, so we were eager to try out this innovative new EFI system from Nitrous Express when we saw it at last year's SEMA show. While most nitrous systems for fuel-injected cars have been somewhat limited, NitrousExpress has a new line of NXL systems that essentially act as direct-port injectors, making the system far more capable than a traditional plate system that sandwiches between the two halves of the 5.0L's intake manifold.
Nothing to see here, move along.
The NXL system employs a series of nozzles that fit between each fuel injector and the manifold to deliver nitrous and fuel directly into the combustion chambers like direct-port injection. Additional enrichment fuel is supplied by a separate line that connects to the factory fuel system along with the nitrous line routed from a billet aluminum distribution block. From there, two fuel and two nitrous Teflon lines are attached to each NXL nozzle. Don't worry about the integrity of the Teflon lines--they're rated at over 27,500 psi burst pressure and feature an insulated woven mesh, a Teflon inner lining, and a vinyl outer coat. While the NXL system may look complicated, the nozzles promote a much more efficient atomization process by spraying in a cross pattern directly into the cylinder. We also like the idea of having an independent fuel source for our power adder instead of a dry system that relies on the fuel injectors for additional fuel.
Although we're showcasing this new NXL system on a 5.0L powerplant, you'll be happy to know that this trick new technology is also available for GM LT1 and LS1 engines and Ford's Modular 4.6L engines. The same nozzles used in our kit will drop into all of the previously listed applications with only minimal changes in the length of the Teflon lines. Read on to find out the incredible dyno results.
Fuel-System Upgrades
We can't even begin to tell you the number of times we've heard, "Nitrous is cheating," or, "You'll blow up your motor with noss." The fact is that adding power may require additional upgrades regardless of the method. When problems arise, it's usually the result of ignoring manufacturer recommendations or using substandard components that weren't up to the task of handling the additional power in the first place.
Knowing that we had every intention of going fairly big with our daily commuter, we removed the original 130,000-mile fuel-system components and upgraded the fuel system with a Mallory fuel pump and fuel regulator, ACCEL 24-lb/hr injectors, and a larger 80mm mass-air meter from Granatelli Motor Sports (GMS) calibrated to match the injectors. If you find yourself debating between factory replacements or performance upgrades for maintenance components, keep in mind that many of the upgrades we've selected don't cost substantially more, will ultimately provide better peak performance, and can offer better peace of mind.
Out back we replaced the factory's weak 88-lph fuel pump with a high-performance Mallory unit rated at 255 lph. The new pump is a direct factory replacement and came with all the necessary hardware for the swap. The entire job took less than an hour, including dropping the tank, removing the two strap bolts, unplugging the wiring harness, and swapping out the old for the new. | 
Swapping to the 255-lph fuel pump also required changing out the fuel regulator. Since the factory unit doesn't have the capacity to return the higher volume of fuel, it can cause a high-pressure buildup on the pressure side and eventually blow out the regulator's seals. To prevent this, we installed a Mallory regulator that will also allow us to adjust the fuel pressure higher or lower as needed. For now we left the pressure at the factory's 38-psi setting. |
Our original 19-pound injectors had served the motor well for 14 years, however, this was a good time to replace them with a fresh set of high-flowing ACCEL 24-lb/hr injectors. Don't bother trying to salvage the old ones; it's cheaper to replace them with quality aftermarket units like these. ACCEL offers a wide variety of flow ratings to choose from depending on the amount of modifications currently on your vehicle. | 
Swapping out the restrictive air-inlet box and mass air meter took no time at all. Just unplug the mass-air-meter harness, unbolt the inlet from the throttle body, and remove the mass-air-meter bracket from the strut tower |
. Reverse these steps to install the monster 80mm GMS meter. | |