When 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.
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.
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.
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.
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.”
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
“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.”
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
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.
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.
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.
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.
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.
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:
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?