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Wet vs Dry Nitrous – How To Choose – Nitrous 101

October 9, 2019

When you hear racers talk about nitrous, ears
perk up, eyes widen, and the imaginations run wild. Nitrous oxide is nothing more than a gas that
contains a higher oxygen concentration than the atmospheric air alone. It’s typically stored under high pressure
as a liquid in specialized bottles, some dentists even use nitrous oxide as a sedative, we know
it better as laughing gas, but it’s not quite the same as what we use for racing. Automotive grade nitrous contains a small
amount of sulfur mixed in and can be harmful if not used properly. Nitrous oxide can be injected into an engine
as either a liquid or gas form, as a liquid though, it must first change states from a
liquid to a gas before it can be used for making power. Extreme heat within the combustion chamber
causes the nitrous molecules to split, the extra oxygen that’s left over from the separation
allows you to burn more fuel, which in turn makes more horsepower. There’s also another advantage to nitrous,
the change in state from a liquid to a gas is known as vaporization. This actual vaporization process causes a
rapid drop in temperature making the incoming air-fuel mixture much denser, which helps
to make more power. These benefits, along with the ease of installation
makes nitrous oxide an attractive power adder, but before running out and buying that nitrous
plate or direct port system, there are a few things that you’ll need to know. Two terms you’ll probably here when talking
about nitrous are wet and dry systems, these terms refer to the method in which the additional
fuel is added when a nitrous system is activated. A wet system adds additional fuel with a separate
pump through the same plate or nozzle supplying the nitrous oxide. The complete system is activated by a switch,
either controlled by the driver or set up on a throttle linkage. The switch activates a set of solenoids for
both the nitrous and the additional fuel. The amount of the fuel added is determined
by the jet size installed in the plate or nozzle. This jet is basically a calibrated restriction
that can be swapped out for a differently sized orifice in order to obtain the desired
air-fuel ratio. Wet nitrous systems are typically used on
carbureted engines but many EFI applications also use this design since you usually don’t
have to make significant or sometimes expensive changes to your existing fuel system. A dry nitrous system relies on the existing
fuel system, whether it is fuel injected or carbureted to supply the additional fuel needed
when the nitrous system is activated. This means the nitrous plate or nozzle only
supplies nitrous oxide, no additional fuel is added here unlike the wet kit. A dry nitrous system can be activated with
a switch much like the wet system but typically it’s controlled by your fuel injection controller
or ECU. This allows the EFI system to calculate and
determine when and how the additional fuel is going to be added. More advanced systems such as the Holley Dominator
and HP EFI systems can pulse, delay, or otherwise control the nitrous solenoids based on a multitude
of predetermined parameters that you can set within the ECU’s programming. Knowledge is a must when it comes to determining
which system best fits your needs. Start with your current set up and determine
what expectations you have. Take into account your budget, mechanical
abilities, and system limitations when you are selecting the kit that is right for you. And don’t forget to think about your future
plans. This can help avoid any unnecessary upgrades
and modifications should you choose to increase that nitrous shot in the future. Whether you need a complete wet or dry nitrous
system, or you are just looking for a few pieces to upgrade your current set up, with
a huge variety of options and applications available, look no further than NOS, your
nitrous leader. Thanks for watching, for more information
on our full line of nitrous products, visit our website at


  • Reply Mason July 18, 2018 at 1:34 am

    In other words go for a wet system if you don't like EFI lol

  • Reply Robert DeLong September 10, 2018 at 12:57 am

    You need to add a Harley Carb install video

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