Perimeter Plate Nitrous system - Go, Baby, Go!

The ins and outs of installing a nitrous system

Jeremy D. Clough Mar 8, 2012 0 Comment(s)
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The first part of installing nitrous is the actual plumbing, starting with mounting the bottle in the car. While putting it in the passenger compartment is generally frowned upon, if you've got a Corvette, that's pretty much where it's gotta go. From the bottle, the nitrous passes through a braided-steel line to a solenoid that mounts near the intake manifold. When the solenoid receives an electrical signal, it opens a valve, releasing the pressurized nitrous through another braided line into the perimeter plate, where it's mixed with fuel and sprayed into the intake manifold. Where the line meets the plate, it screws onto a fitting that accepts one of several different jets, or "pills," that meter how much nitrous gets in. These are marked with different numbers, and the kit specifies which one is required, and which fuel jet should accompany it in order to deliver a certain power level.

Traditional "plate" nitrous systems use a roughly half-inch-thick plate that fits between the manifold and the carburetor or throttle body. Generally, the plate has a perforated tube that runs across its middle, and the nitrous/fuel mix is sprayed from that tube. The Zex perimeter plate, however, uses a series of channels machined into the plate itself (actually two pieces screwed firmly together) to mix the fuel and nitrous and then spray the mixture through 12 different ports. The result is more-even distribution. (For those who already have a conventional plate system, the Zex perimeter plate is available separately.)

For fuel delivery, a fuel line must be added to the existing one and run to the fuel solenoid. This was the only necessary component that wasn't included in the Zex kit, likely because fuel-delivery systems vary so much between vehicles. Since this car has a 3/8-inch fuel line, I added a 3/8-inch brass tee to the stock line and ran the additional one from there. When the solenoid is activated, fuel goes through a braided line to the opposite side of the plate; this line screws onto a fitting containing the appropriate jet.

The system is activated by a switch in the cockpit. To install it, you'll need to splice into a source of switched power at the fuse box. This wire will then run to the toggle switch, and from there to a relay mounted in the engine compartment. A relay is generally used when you need to run more power to something than it's safe to put through a simple 12-volt toggle switch. The power required to operate whatever it is--here, the nitrous solenoid--comes from a direct power source, such as the alternator or battery, to the relay. A separate arming switch then "turns on" the relay, which is essentially a heavy-duty switch.

In addition to the power coming in from the alternator and the arming switch in the cockpit, the relay also has a contact for a ground wire, which you'll want to mount to the intake. There's also a contact for the power going out to the solenoids, each of which also will need to be grounded. Although I'm a relative novice at electrical work, the diagram and instructions that come with the kit are quite clear, and I had no trouble putting it all together.

The only other electrical components required are an inline 30-amp fuse for the power coming into the relay, and a throttle switch. Since nitrous can damage the engine if it's run at low rpm, many systems use a microswitch, mounted on the carb or throttle body, that only activates when the engine is at wide-open throttle. This switch is wired into the arming circuit, so that the wire coming from the arming switch in the cockpit goes to one side of the throttle switch, and another wire leads from the other side to the relay. The circuit is only closed when the arming switch is on and the throttle switch is activated.




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