| Nitrous Oxide FAQ and Myths Dispelled - Squeezin'
Nitrous oxide is one of the most misunderstood power-adders on the market. It has a reputation for being unsafe or unethical, but pound per dollar, nitrous is the most inexpensive and easiest way to make a lot of power. And it's just a lot of fun. If you understand it, N2O is a great tool to get you down the 1320 as fast as possible.
Over the past few years, we've received hundreds of questions about nitrous and its applications. We've tried to answer the most common inquiries and hopefully can dispel some of the myths surrounding the gas. Used properly, nitrous is a viable option as a primary or even supplemental power-adder foor your car.
Q: How does adding nitrous create more power?
A: N2O is one part oxygen (36 percent) and two parts nitrogen (64 percent). It has a significantly larger percentage of oxygen content than ambient air. Combustion temperatures cause nitrous to break down and release oxygen. The added oxygen in the intake charge allows more fuel to be burned, and the more fuel a car can burn at once, the faster it will go.
Spraying oxygen by itself would result in a violent, uncontrolled burn. The nitrogen acts as a buffer to control the combustion. Nitrous also acts an intercooler, especially on turbo cars, which can drop the intake charge temperature by more than 50 degrees F.
Q: Is it safe to spray nitrous, even if the engine is stock?
A: Nitrous only adversely affects engine reliability when used incorrectly or excessively. As with any power-adder, increased engine output from nitrous oxide raises the stress on internal components. Going with a large "shot" on a completely stock motor is a bit optimistic. Be realistic about how much your engine can handle-that's the best way to keep everything in working order while using nitrous.
You can use nitrous on a stock engine without problems. Most nitrous kit manufacturers recommend using a 60-hp shot or less on a stock motor. Fortify your internals with stronger aftermarket and you can get away with using more N2O.
Q: Can nitrous be used on a high-mileage engine?
A: High miles aren't necessarily indicative of a worn-out engine, especially in the Honda world. You can spray on an engine with any amount of miles on it as long as all the components are in good condition. Do a compression test to make sure your rings, head gasket and valves are sealing. If the compression test is good, go ahead and use nitrous.
Nitrous won't cause problems on a high-mileage engine, but it will make pre-existing problems worse.
Q: Will N2O damage the catalytic converter?
A: No, nitrous doesn't raise exhaust gas temperatures long enough to negatively affect the cat. The extra oxygen might even help it be more efficient.
Q: Can a nitrous kit be used on an automatic transmission?
A: Absolutely. Automatics are perfect for nitrous. Punch the throttle, hold the button and go!
Q: Can nitrous be used on forced induction applications? What about high-compression, all-motor applications?
A: Turbo'd and supercharged cars usually respond better to nitrous than all-motor cars. Turbo lag is easily displaced by a nitrous system spraying off the line. More importantly, nitrous acts as an intercooler and can lower the intake charge temperature by more than 50 degrees. These effects are both gains in addition to what it would make on a naturally aspirated car.
The same jetting used to make a 75-hp shot on a naturally aspirated motor might make 100 hp or more on a turbo or supercharged application because of the added benefits nitrous has in forced induction situations.
Nitrous works well with most applications, though. Even high compression, N/A motors can use nitrous. In high compression motors the nitrous/fuel ratio needs to be finely tuned, usually with a wideband on a dyno. You'll need to retard timing; 1.5 to 2 degrees per 50 hp is good.
Q: What steps should be taken in order to run a lot of n2O safely?
A: Forged connecting rods and pistons are the most important components necessary to run a large shot. If you intend to go really big, consider a sleeved block to fend off any lateral stress. Along with fortifying the structural parts of your engine, you'll need to upgrade some of the peripheral parts.
A lean mixture when nitrous is engaged will lead to detonation, which leads to expensive rebuilds or engine replacements. A high-flow fuel pump can help protect your engine from leaning out. Another way to avoid detonation is to retard static timing. Most manufacturers recommend between 1-2 degrees retard per 50-hp increase. Also, with very large shots (more than 100 hp) it's a good idea to lower the heat range of your spark plugs and opt for using race fuel.
Q: Will nitrous oxide cause detonation? Can nitrous be used in conjunction with pump gas and not cause detonation?
A: Nitrous itself will not cause detonation. If you're spraying nitrous and your fuel system isn't working to its potential, your mixture will lean out and cause detonation.
Most nitrous kits manufactured today include a way to control fuel. Again, it's also a good idea to retard static timing 1-2 degrees for every 50-hp increase.
If you're running a small shot (70 hp or less), pump gas works fine. Just make sure you're filling with premium (91 octane or higher) juice. For race applications utilizing high-compression engines or large shots of nitrous, we recommend a high-octane (100 or higher) race fuel.
Q: What are the differences between a dry and a wet kit?
A: A dry system squeezes more fuel out of your factory injectors by boosting fuel pressure. Dry kits are cheaper and easier to install than wet kits. The trouble with dry kits is that the fuel isn't atomized with the incoming nitrous.
For example, let's say cylinder four isn't receiving as much nitrous as cylinder one. Both will still continue to receive the same amount of fuel.
Conversely if one of your fuel injectors is clogged, it might be fine to drive around normally. But when the nitrous is spraying, you'll run lean and get detonation.
A wet kit integrates the additional fuel with the spray of the nitrous oxide itself using a nozzle. With a wet kit, you have both nitrous and fuel solenoids. You can change the nitrous or fuel-jetting orifices to tune a precise mixture of nitrous and fuel.
Q: How long can the nitrous button be pressed? When should I push it?
A: Well, physically, you can hold the nitrous button down until the bottle runs dry. But most manufacturers recommend using nitrous for no longer then a quarter-mile run, whether that takes you 11 or 17 seconds. Nitrous is intended for use in short bursts. You shouldn't be on the freeway holding down the button trying to break a new land-speed record. That doesn't mean you can't spray for 10-15 seconds to edge out that Mustang next to you.
Most nitrous kits come with wide-open throttle switches or TPS switches to either arm or engage your nitrous system. You should only spray at wide-open throttle. The rpm level is not important. Rather, the engine's ability to rev freely is key.
Spraying at less then 2500 rpm is OK in second, third, or even fourth gear because the engine can easily accelerate as the car goes faster. Low speed in fifth gear might cause problems, as you're asking the engine to try a lot harder, rev higher and get up to speed faster.
Q: How long does one bottle last? How much does it cost to get a bottle refilled?
A: Depends on how large a shot you're running. On a shot of less than 75 hp, a 10-pound bottle will probably get you 15 to 17 quarter-mile runs. The more you spray, the more often you'll fill up. You'll get seven to nine passes out of a 200-shot. Here's the formula:
0.8 lb of N2O x 10 seconds = 100 hp
So if your system is jetted for 100 hp, it will use 0.8 pounds of nitrous for every 10 seconds of squeeze. Depending on where you live, nitrous should cost between $3-5 per pound.
Q: Could there be an increase in performance if medical-grade nitrous oxide is used?
A: Why? You know a dentist or something? No, there isn't much difference between medical- and automotive-grade nitrous except that automotive nitrous includes a 100-ppm dose of sulfur dioxide. This makes the gas taste really horrible and it can make you sick if you inhale it. The sulfur is a direct deterrent to huffing this stuff to get high. Believe us, we've known a couple of rocket scientists who've tried.
Q: Is nitrous oxide flammable?
A: Nitrous oxide is not flammable. It does, however, accelerate the rate at which a pre-existing fire burns. Nitrous isn't considered a fire hazard.
Q: Purge valves look rad. What's their deal?
A: Nitrous works better in liquid form. The liquid state is usually only maintained under high pressure and low temperature (i.e. when it's inside the bottle). Once the nitrous leaves the bottle, it wants to change into a gas. While nitrous is engaged, this isn't a problem because it's flowing fast enough to stay liquid all the way into the cylinder.
After you let off the throttle, though, the solenoid closes and some nitrous still remains in the lines in a gaseous form. A purge valve is designed to get rid of the gaseous N2O and leave behind ready-to-rock liquid. This gives you a split-second advantage by having that initial bite ready to go when the spray is engaged. Necessary? No. But get one anyway. It's a performance advantage and looks hot.