Jon Mikelonis of Fordmuscle.com takes us through his first carbed nitrous install on a 460 powered 1973 Torino
Nitrous Oxide (N20) isn't for everyone and during my first nitrous install, I wasn't sure it was for me either. Afterall, I don't race nor do I have any near term plans to increase my amount of wide-open-throttle street driving. Nonetheless, I still enjoy getting familiar with performance items and gaining technical experience like most of the FordMuscle community. But most of all, as it relates to writing for FordMuscle, I have a passion for demystifying the seemingly complex, overly technical, or ultra-intimidating. In this article, I will take you step-by-step through a carbureted Nitrous install in order to help you decide if hitting the bottle is right for you. Introduction
Feature car flicks like Stallone's Cobra sometimes portray Nitrous Oxide systems as very rudimentary "flip-of-the-switch" sources of high horsepower. If you have never installed a N20 system, you'll soon find out that a proper system goes beyond a basic dash mounted toggle switch, solenoids, and bottle.
Whether it was Stallone in Cobra or Mel Gibson in Mad Max, there has always been an allure for car guys to the concept of flipping a switch for an instantaneous high increase in horsepower. However, Hollywood's use of creative freedom for cinematic impact has lead to many misconceptions about Nitrous Oxide as well as creating high expectations for the enthusiast. With that said, going into my very first nitrous install, I was sure to lower my own expectations and accept a fair level of troubleshooting before realizing any immediate power gains from my 460 powered 73 Torino.
For background information on the science of Nitrous Oxide be sure to read the first page of FordMuscle's article Bottle Feeding. In addition to that article, here are three additional facts that will prepare you for reading the install and pictorials to follow on the next four pages.
In the most basic form, a proper Nitrous Oxide system uses three "switches" to introduce N20 into your intake charge; a primary interior mounted "arming" switch, a wide-open-throttle (WOT) switch, and a RPM window switch. This mini network of switches should erase any notion you may have that the flip of one single switch will instantly peg your tachometer.
Modern nitrous kits and aftermarket ignitions have greatly increased the ability to control the timing, amount, and duration of the "shot", making nitrous safe for OE motors and yourself when "programmed" and installed correctly. In other words, you don't need a bullet proof bottom end for nitrous if you correctly design a 100HP nitrous system.
Common problems with nitrous are insufficient fuel pressure, poor bottle temperature control, running too much timing, and activating nitrous at too low of an RPM.
For a good overview of common myths and misconceptions regarding nitrous, the article N2O Myths
at Competition Plus is also recommended. Micro WOT Switch
Most nitrous kits include a interior arming toggle switch and a micro wide-open-throttle switch. While this is enough to make a nitrous system function, including the third parameter of an RPM window switch will make a N20 system even safer. Ignition Considerations and Installation
Nitrous Oxide systems are designed for use at wide-open-throttle. N20 Kits include a micro WOT switch that is mechanically activated by your throttle linkage. Installed and positioned correctly, this switch ensures that when the system is armed, via an interior toggle switch, the nitrous shot is only introduced at WOT. However, a proper Nitrous Oxide system doesn't stop there. In order to protect your motor and yourself, it's important that Nitrous Oxide is not only used at WOT, but also at a predetermined RPM range above 3000 RPM. The added measure of RPM range activation, prevents the Nitrous shot from being introduced into a low velocity air/fuel charge which can wreak havoc on your motor.
Combine the need to "program" this RPM range into your system with the general rule of retarding your ignition timing by 2 degrees for each 50HP shot of nitrous, and you'll need an ignition controller (MSD or Mallory) to safely run Nitrous on a carbureted application. The MSD Digital Programmable 6AL-2 and the Mallory HyFire 6.6 Multi-Strike CD Ignition are two market offerings that will get the job done as single units. There are many manufacturers of accessory RPM window switches that can be tied into standard CD ignition boxes like the MSD 6AL or Mallory HyFire 6AL. In the simplest form, an ignition controller serves two purposes for a Nitrous Oxide application:
- Determines what RPM range to activate and deactivate the Nitrous Oxide during WOT
Wiring Schematic for Mallory HyFire 6.6 Multi-Strike CD Ignition
- Determines the amount to retard the ignition timing throughout the programmed RPM range
With that said, before getting involved with choosing or installing a nitrous system, our carbureted 460 Ford application would need an ignition controller to satisfy 1 and 2 above. We took on installing, tuning, and testing a Mallory HyFire 6.6 CD Ignition Controller. View The Ignition Controller Installation Photos Nitrous Bottle Mounting and Main Line Install
With the new ignition installed, it was time to begin installing the Zex nitrous system. I picked up the base kit itself from Summit for around $600.00. However, the kit does not include a pressure gauge for the bottle or a bottle heater. These are two items that FordMuscle and myself agree are necessary even for a basic first time nitrous system. Bottle heaters are surprisingly expensive for what they do at about $130.00. The Zex gauge ran for $45.00.
First, I found a nice location just behind the passenger seat in the trunk to mount the bottle.
After marking and drilling four holes, I got underneath the car and tightened the hardware. This is a little something I learned
to do when working alone (see four combination wrenches).
Here's the gauge I picked up in addition to the kit, the gauge is critical for verifying that your bottle pressure is at least between
900 and 1000 psi for proper function.
The gauge being installed carefully.
The bottle mounted.
I knocked a 1" hole in the trunk floorboard to route the main nitrous line.
I added a grommet to protect the line from sheetmetal.
Here I am popping the line up through the trunk floorboard heading for the nitrous bottle.
The main line attached to the bottle.
Next, I began routing the main line along the frame of the Torino.
I tied wrapped the line along the way.
In fact, I just ran the line along the factory fuel lines from the trunk to the motor compartment.
Here's a shot of the main line routed all the way up to the motor compartment. Nitrous Bottle Heater Install
The key to getting the advertised horsepower power from any nitrous system is maintaining proper and consistent bottle pressure. As with any compressed gas, pressure is a function of volume and temperature. A full bottle will have higher pressure than one near empty. A cold bottle will have lower pressure versus a warm bottle. Nitrous systems work as advertised when the bottle pressure is 900-1000 psi. With lower pressures nitrous flow will be reduced and the resulting nitrous-fuel mixture will be excessively rich. Higher bottle pressures will lead to a dangerously lean mixture.
One can imagine that with fluctuations in outside temperature, and as nitrous is consumed, achieving consistent nitrous performance can be challenging. The solution is to control and monitor bottle pressure. Using a nitrous bottle heater we can apply heat to the bottle exterior in a safe and gradual manner. A thermostatically controlled switch makes the task fully automated, however simply monitoring a pressure gauge also gets the job done properly. We donít recommend applying heat via a torch or other methods, as pressurized cylinders quickly become bombs under too much heat. When the pressure is between 900-1000 psi you can be assured that the nitrous flow is matched to the fuel jetting, resulting in the proper mixture, therefore a bottle heater is a mandatory part of a proper nitrous system.
Read The Conclusion Of This Article At www.fordmuscle.com