NX Express_edited-1When it comes to performance modifications, it’s undeniable that nitrous is one of the best bang-for-your-buck options out there. Dollar for dollar, you simply can’t buy more performance for less cash. However, like any significant performance modification, certain guidelines must be respected in order to reap the benefits of the mod and to be able to continue to use it safely and reliably without causing undo harm to your engine.

Nitrous Express has taken a lot of the guesswork out the equation with their new pre-plumbed intake manifolds, which come with everything a builder would need pre-installed, tested, and ready to be bolted up.

But before we get into the details of the NX direct port system, let’s take a closer look at the various options currently available to those looking to add a nitrous system to their arsenal to get a better sense of all the advantages offered by the Nitrous Express kit.

Adding Spray

A dry nitrous system configuration injects the goods into the intake tract, while the fuel required to make the additional power is introduced through the injectors, keeping the upper intake dry of fuel. To make the system function as intended, the engine’s controller must be modified in order to ensure that it feeds enough fuel into the system to generate the additional power offered by tossing nitrous into the mix. While dry systems’ simplified plumbing makes them relatively easy to work with, the main drawback is its reliance on the ECU to deliver the additional fuel needed. If it doesn’t keep the motor properly fed it can cause a lean condition in the fuel system, and that can lead to a very bad day for the engine.

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Adding a nitrous system is one of the most cost effective ways to seriously boost your engine’s output, but there are some considerations. While wet systems reduce the potential for a lean condition that could cause engine damage, the setup is significantly more elaborate than a dry system. Nitrous Express offers pre-plumbed kits that take much of the guesswork and hassle out of the install, as they come pre-plumbed into the intake manifold of your choice and configured for your vehicle (both in terms of engine configuration and engine bay packaging) and output requirements.

Wet systems, on the other hand, introduce both fuel and nitrous together simultaneously, and rather than duping the engine controller into delivering the additional fuel, the fuel system itself is typically modified to ensure the delivery of the juice required. The key advantage with this configuration is that instead of relying on the ECU to deliver the additional fuel, a fuel solenoid does the job instead, eliminating the possibility of grenading the motor due to a lean condition.

Direct port kits are a derivative of wet systems and introduce nitrous and fuel directly into each intake port of the engine. By putting a nozzle in each runner and utilizing a modular configuration that allows the system to be tailored to a specific application, direct port systems allow for the mixing and metering of the nitrous and fuel delivered to each cylinder individually, allowing each cylinder’s mixture to be adjusted independently of the other cylinders. This in turn yields a far more efficient and accurate type of nitrous system, but it’s also one that’s substantially more complex as well, as the intake manifold must be modified to accept the system’s plumbing, and the plumbing itself has to be configured to work within the confines of a particular engine bay.

Nitrous Express offers multiple nitrous nozzle designs to provide an ideal injection point for a variety of intake runners. Customers can choose from multiple solenoid options as well as multiple distribution block styles, including center mounted distribution blocks, showerheads or rail style distribution blocks as seen above.

NX’s pre-plumbed intake manifolds offer a compelling alternative that can save builders a lot of time and hassle. The kit combines a brand new intake with a direct port system that’s been pre-installed by the technicians at NX so that a builder can simply take the intake out of the box and install it on the engine. This approach seriously cuts down on potential hassles, as each component of the nitrous system in the kit is inspected after being setup by NX’s techs and the entire setup gets leak checked and flow tested before it goes out the door. We hooked up one of these kits to our LS3 from the LS3 vs Coyote Budget Shootout and headed out to Westech Performance to put the new setup on the engine dyno to see what it could do for our street-tuned LS3.

The Kit

If you’ve been searching for a truly dialed in direct port setup right out of the box, look no further. “NX offers multiple nitrous nozzle designs to ensure the perfect injection point in a variety of intake runners,” says Ryan Lewis of Nitrous Express. “Customers can choose from multiple solenoid options as well as multiple distribution blocks styles including center mounted distribution blocks, showerheads or rail style distribution blocks, so they can rest assured the nitrous system will be installed correctly, look great and will be ready to make power.”

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The beauty of the Nitrous Express kit is how much it simplifies the installation process, and the fact that you know ahead of time that components chosen are properly matched to your setup doesn’t hurt either. Along with the intake, the system includes eight nozzles, two nitrous solenoids, a pair of fuel solenoids, and anodized aluminum distribution blocks, and stainless hard lines and fittings – all of it already plumbed on the manifold when you take it out of the box. Systems include jetting for a wide range of horsepower levels, 6AN nitrous feed lines, a wide open throttle switch, 40 Amp relays and relay harnesses, master arming switch, stainless bottle brackets and a 10lb nitrous bottle with the NX Lightning bottle valve.

During the install process every component is inspected, every tube is deburred and every system is leak checked. When you have NX install your direct port you can rest assured that the system will perform perfect right out of the box. -Ryan Lewis, Nitrous Express

The NX system consists of eight NX nozzles, two NX Lightning-series fuel solenoids, two Lightning-series nitrous solenoids, anodized aluminum distribution blocks, 3/16 stainless hard lines, and stainless steel fittings, and it’s all plumbed and installed on the manifold of the customer’s choosing. Also included in the kit is the jetting for 200-500 horsepower, a wide open throttle switch, 6AN feed lines for the nitrous, 40 Amp relays and relay harnesses, a master arming switch, stainless bottle brackets and a ten pound nitrous bottle with the NX Lightning bottle valve, making this kit as plug and play as a builder could hope for.

“Every system starts with straight lines and is custom bent by the hands of the custom installers here at NX,” Lewis adds. “During the install process every component is inspected, every tube is deburred and every system is leak checked. When you have NX install your direct port you can rest assured that the system will perform perfect right out of the box. Using a state of the art flow bench, we flow nitrous and fuel through the nitrous system and provide a comprehensive jet sheet with flow data in pounds per hour. We also provide fuel pressures required to achieve varying nitrous to fuel ratios ranging from rich to lean. We also offer custom flowing services for customers who have a unique combination of parts or who want exact flow data on their specific components.”

After a customer gives Nitrous Express a rundown of their vehicle setup and how much power they want to make with the kit, NX technicians put together a system based not only on the engine application but the packaging requirements of the engine bay that the system is going in.

NX Lightning solenoids feature an improved flow path that allows nitrous and fuel mixture to enter above the seat and exit out the bottom for flow unmatched by any other solenoid on the market. -Ryan Lewis, Nitrous Express

And as you’d expect, the materials used in the kit’s construction are high quality stuff. “We use one hundred percent stainless hard lines, billet aluminum distribution blocks/rails, billet aluminum and carbon fiber solenoids, and stainless or aluminum nozzles depending on the customer’s preference,” Lewis says.

The Lightning series solenoids that are included in the kit are NX’s latest and greatest, featuring an improved flow path that allows nitrous and fuel mixture to enter above the seat and exit out the bottom. “The flow is unmatched by any other solenoid on the market,” Lewis tells us. But he says that’s just one of the numerous improvements and features of these solenoids.

“Lightning nitrous solenoids also have an integrated purge port that allows you to connect a purge valve directly to the nitrous solenoid – purging through the body of the solenoid eliminates the air pocket between the purge valve and the solenoid orifice. The fuel solenoids also have a fuel bypass port which allows you to connect a small return line to the tank. This eliminates trapped air between the fuel pressure regulator and the fuel solenoid which eliminates the lean spike associated with other solenoids.” The Lightning series solenoid bodies are made from CNC aluminum and are topped with carbon fiber cans, so they’re light weight and look sharp under the hood too.

Every system starts with straight lines which are custom bent for the specific application they're to be used in by the technicians at Nitrous Express. During the install process every component is inspected, every tube is deburred and every system is leak checked. NX uses stainless hard lines, billet aluminum distribution blocks/rails, billet aluminum and carbon fiber solenoids, and stainless or aluminum nozzles depending on the customer’s preference.

For our application we selected a pre-plumbed FAST 102 intake to bolt atop our LS3 – this intake has been proven to build power on mildly built LS motors like this LS3 in the past, so we knew it was a safe bet. For LS motors, Nitrous Express offers pre-installed kits for this manifold as well as the stock LS3 intake and the Holley Hi-Ram, though they’ll also do custom work upon request as well. “We can plumb a direct port nitrous system on any intake manifold and custom flow each system for whatever horsepower levels the customer chooses,” Lewis adds.

In terms of jetting, Lewis says NX determines that on a case by case basis. “Jetting varies depending on the nitrous system and the fuel pressure that is supplied to the nitrous system – requirements are first calculated on a flow bench and then tested on a running engine to make sure the horsepower and nitrous to fuel ratio is as accurate as possible.”

Before we hit the dyno, let’s take a closer look at the powerplant this kit is getting installed on.

The Engine

This LS3 from our LS3 vs Coyote Budget Shootout has become something of a test mule motor for us. The criteria for the shootout itself makes this engine a great test mule for this sort of thing by design, as it was intended to be the kind of engine an enthusiast could put together in their garage for a reasonable amount of money. Additionally, rather than putting together a combination aimed sheerly at posting the highest numbers possible, we took a more measured approach, as we wanted the motor to be eminently streetable, reliable, and serve as a solid foundation to build power on.

While the intention of the LS3 vs Coyote Budget Shootout was to see what kind of power we could make with each motor under a specific set of real-world criteria, we wanted the motors to be streetable, reliable, and ready for more power to be added down the road. Accordingly, the LS3's bottom end is fairly stout, and uses all forged components, making this a great test mule for the NX kit.

To that end, we’ve got forged internals on the bottom end, with an LSA crankshaft from Pace Performance (PN 12641691), Lunati connecting rods (PN 70361251-8), along with a set of forged Mahle pistons (PN 197714865) and rings (PN HV385). A Comp Cams camshaft (PN 54-469-11) and a matched set of springs are paired with Dart Pro1 cylinder heads. Along with the other requisite odds and ends we used for the build, it’s a combination that made 556.3 hp at 6,500 rpm and 497.2 lb-ft of torque at 5,500 rpm on the dyno with the stock LS3 intake manifold.

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With the stock intake manifold bolted up, the LS3 made 556.3 hp at 6,500 rpm and 497.2 lb-ft of torque at 5,500 rpm during our initial round of dyno tests last year. Solid numbers considering this isn’t a particularly radical setup, but this engine is undoubtedly ripe for power adders like nitrous and/or forced induction.

With a stout bottom end already in place, we knew we could safely add a healthy shot of nitrous to the mix without any potential trouble. But it’s worth noting that even a stock LS3 can handle a reasonably stout shot.  A stock LS3 can usually take 150 hp of nitrous in stock form, and up to 200hp with race fuel,” says Lewis. He points out that a good rule of thumb for retarding timing is to dial back two degrees for every 50 hp of nitrous, ending up with a total of 19 degrees.

For our kit, NX included their Shark nozzles. “The FAST 102 manifolds require us to use a Shark nozzle due to the way FAST designs the bungs on the manifold,” Lewis explains. “Aside from necessities like that, when putting together a customer’s system we determine which solenoids to use by asking the customer how much nitrous they want to flow at a maximum, and from that point we need to know what vehicle the manifold is being installed in and plumb it up accordingly.”

While both are made of aluminum, the Shark type nozzle is larger (1/8-inch NPT) than NX’s Piranha nozzle and will flow a max of 250 hp per nozzle. Piranha nozzles are more compact (1/16-inch NPT) and will flow a max of 150 hp per nozzle. It’s also worth noting that NX offers several other nozzle types in different shapes and materials as well, so be sure to touch base with them before ordering your kit if you have specific requirements.

The Results

With the NX-plumbed FAST 102 intake installed, we put the LS3 on the dyno at Westech. We introduced the nitrous into the system around 5,600 rpm, showing peaks in both horsepower and torque at about 6,100 rpm:

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With the NX-plumbed FAST 102 intake bolted up to the LS3, we went for another dyno pull. You can see that once the spray kicks in around 5,600 rpm, the surge of power is pretty dramatic – the engine builds an additional 200 horsepower within 500 rpm, peaking with 737.5 horsepower and 633.4 pound-feet of torque at 6100 rpm. In terms of tuning, we pulled 8 degrees of timing from the peak naturally-aspirated run, and for jet sizes we used .022-inch for nitrous and .012-inch for fuel.

As you’d expect, when the shot hits the output ramps up in a serious hurry, with the horsepower figure jumping up more than 200 hp in less than 500 rpm. With some small tweaks, there’s undoubtedly more power to be had here, but right out of the box we’ve got some serious output gains with minimal hassle.

Sound interesting to you? Give the folks at Nitrous Express a shout and see what they’ve got for your ride. NX treats every manifold kit as bespoke order, so you’ll want to give them the details about your current setup so they can configure your kit around it. “Every manifold is different and we plumb each manifold differently depending on what type of vehicle it is going on so we can insure there are no interferences with hood or firewall clearances,” says Lewis. “We keep the FAST manifolds in stock here at NX (along with other popular options) and we plumb them up custom to the customer’s vehicle as orders are received. Intakes usually ship with a custom direct port only two or three days after the order is placed.”

So, what’re you waiting for?