NOS Nitrous Oxide Systems: Under Carb Plate Injector Installation and Test

When you decide to make the leap to N2O (nitrous oxides chemical name and common slang) there are a few things you need to know before ordering your kit. You need to ask yourself the following questions:

1: How much of a power increase will my current engine sustain?
2: How much Money do i want to spend?
3: How will this affect my insurance?
4: Do i have a local source for Nitrous gas?
Lets break down each question one by one and then we’ll get on to the installation.

#1 This is a question for tech support at NOS. They will need your engine specs including cam numbers, compression ratio, type of exhaust and intake manifolds and fuel deilvery (carb or EFI).

#2 The amount of money you want to spend is up to you. A basic plate N2O system can be as little as $750. A complex double solenoid, double nozzle fogger system can run you $5000.

#3 How a N2O system affects your insurance is dependant on the company. My Ranger is insured with state farm and the installation caused no increase in the premium. I helped a freind install a system on his Civic and his monthly insurance bill DOUBLED! IT pays to check this out before you buy.

#4 You will need to have a source for Nitrous gas at a local level. Most Carquest and NAPA stores will send your bottles in and have them filled. Some local “speed shops” fill them on-site.

Now on to the installation!

First and foremost is safety. NEVER EVER inhale N2O gas! This gas displaces oxygen and inhaling it can lead to brain damage and possibly death. DO NOT play around with your tanks. If the bottle valve broke off from being dropped or tipped over you could be seriously injured or killed.

I custom ordered my kit from NOS so i got exactly what i ordered for. Most universal kits will have a set of jets to install in the plate and you select the proper jets for your application. Mine were pre-selected so all i had to do was install them. The kit came with the following:
10 Lb bottle ( i ordered three spares at the same time)
Plate kit with all fittings, jets and piping
Solenoid kit with fuel and nitrous solenoids
Bottle control solenoid
15′ nitrous feed line
Bottle brackets
several misc. nitrous lines
Wiring kit
Switch kit with master switch, bottle control switch and fuel pump switch.

From aftermarket sources i got the following:
7 PSI electric fuel pump
fuel pressure guage
Nitrous pressure guage
Misc. wire ends, fuel line and fittings.

To begin the installation i disconnected all lines and linkages from the carb and removed it. My ranger runs a 2 barrel holley 450 CFM carb that is very easy to tune and install/remove. I cleaned all debris from the carb mounting flange and upper intake. The gaskets that came with the kit did not fit correctly and i had to use Ford 2 barrel carb base gaskets. This is one of the “mix-and-match” parts of modifying cars. You have to find what fits and will work when the factory parts don’t. After finding a correct gasket and installing it, i installed the jets and solenoid connection tubes to the plate injector. MAKE SURE you install the plate the right way. If you install it upsidown it can cause a fuel overspill and fire under your hood. After the plate was installed, i screwed in the longer carb studs that came with the plate kit. I installed the carb but did not hook up any lines or linkages yet.
Next Installed the fuel and nitrous solenoids. They simply screw onto the pipes that are attached to the plate injector. Use teflon sealing tape sparingly. I used rubber fuel lines to run from the fuel solenoid to the extra fuel pump. If you race NHRA you are limited to 12″ of rubber fuel hose and you will have to use AN fittings and line for this. I just drag at local strips and they aren’t picky. The solinoid electrical was wiried as follows: The power sides were wirind to a momentary switch mounted on the shift lever. They were grounded to the engine block. A master power switch for the solenoids was located inside the cab on a switch bank.
The fuel pump was mounted on the driver’s side inner fender with the supplied bracket. I hooked the fuel solenoid up to the supply side and hooked the feed side into the fuel tank draw line. i also added a fuel pressure guage between the fuel pump and solenoid. The fuel pump electrical was wired to a switch bank inside the cab for power and was grounded next to the pump on the chassis.
The nitrous tank was mounted in the pickup box on the passengers side. Note that the tank must be oriented a certain way to feed correctly. Not all tanks are alike and each has a decal denoting its mounting needs. After the tank was installed, I mounted the bottle control solenoid directly on the bottle fitting. This solenoid allows you to leave the bottle open while not keeping pressure on the feed solenoids. It was wired in the same as the feed solenoids. The nitrous line was run from the bottle control solenoid, through the box floor and along the frame rail. I routed it next to, but isolated from, the fuel lines. Car manufacturers spend lots of money finding the most protected place for their lines, i follow their lead. Under the hood the excess line was looped and secured. The end was attached to the fitting on the nitrous pressure guage tee. A second line was run from the nitrous gauge to the feed tee. A third line was run from the tee to the solenoid.

The fuel and nitrous pressure gauges were mounted in a custom built pod on the hood and the lines routed through holes with grommets installed. Initally I used rivets to mount it but later had to remove the pod to fix a leak and replaced them with flush fit bolts and nuts.

The system was tested at a local 1/8th mile strip. The truck ran consistent 11.5 to 11.1 second times before installation of the nitrous kit. I initally bled the fuel and nitrous lines while the truck was idling in the pits. This allowed me to fix a couple small leaks and tie up a loose line before i went through tech inspection. The truck passed tech with no problems. The first pass down the track was timed at 10.8 sec. I adjusted the carb a couple times and made another pass. This one was 10.1 sec. I I adjusted again and made another pass. 9.5 seconds. This was the best time of the day as it was warming up outside and track times were falling across the board.

In conclusion, I gained a full 2 seconds on my run times for an under 1000 dollar investement. Good return for the money. N2O is one of the cheapest power adders on the market, but it is complicated to install and maintain. This installation was a simple under carb plate. Some EFI system can have three times as much wiring and piping to install, plus other computer control components as well. NOS systems are an excellent choice for a moderatly skilled hot-rodder to install themselves. Nitrous systems in general aren’t for beginners, but with assitance they can be mastered. The system on my Rnger has over 400 passes on it with minimal maintenance and no repairs. Excellent durability and reliability.