NOS wet vs dry

here's an article i found that i thought would be helpfull to some of you considering getting NOS

article by Matt Paul.

There are 2 basic types of "bolt-on" nitrous system for the LT1, "Wet" systems, which inject additional fuel externally to the conventional fuel delivery system (the stock fuel injectors), and "Dry" systems, which increase the amount of fuel injected by the stock fuel delivery system. Obviously, there are advantages and disadvantages to each.

Dry nitrous injection systems (I’ll use the NOS 5176 kit as an example) use the stock fuel injectors to add additional fuel into the combustion chamber by increasing the in-line fuel pressure (to the neighborhood of 80 PSI or so). By raising the fuel pressure (and keeping the injector pulse width constant), additional fuel is delivered into the combustion chamber. The NOS kit does this by applying positive pressure to the fuel pressure regulator, which in turn increases the fuel pressure above the maximum stock levels.

This type of system has a few major advantages. First, it requires no plumbing for the additional fuel delivery. Second, fuel does not flow through the entire intake manifold. Lastly, as the nitrous pressure in the bottle fluctuates, the amount of fuel delivered will fluctuate in the same amount (since the system is using the nitrous pressure against the regulator to boost the fuel).

There are some disadvantages to this type of system. First, the stock injectors may lock up at the 80 PSI fuel pressures that the system needs. Second, the amount of nitrous delivered to each cylinder varies slightly (since it will not be consistently distributed in the intake manifold), while the amount of fuel is the same. Either one of these can cause the air/fuel mixture to a given cylinder to go on the lean side.

Wet nitrous systems inject both nitrous and fuel into the intake via a plate between the throttle body and intake manifold or via an injection nozzle (or nozzles) prior to the throttle body.

The biggest advantage to this type of system is that the nitrous/fuel proportion delivered to each cylinder is consistent (although the amount delivered varies from cylinder to cylinder for the same reason that the amount of nitrous delivered varies with a dry system).

The disadvantages to this type of system are that since the manifold isn’t designed to flow fuel, the fuel may puddle in the intake manifold (although a good rev on the engine after shutting down the nitrous system will clear this). Second, the nitrous solenoid will have to be periodically rebuilt (the seals deteriorate slightly due to the exposure to the fuel vapors). Lastly, if the nitrous pressure fluctuates too high, it may cause the air/fuel mixture to lean out on some cylinders

As you can see, the common disadvantage to each system is the lack of a consistent amount and/or ratio of nitrous/fuel to all cylinders. The "cure" to this is a direct plumbed nitrous injection system. These types of systems use individual nitrous/fuel injectors for each cylinder, but are mucho expensive!

After deciding on your nitrous system of choice, there are a number of other items that need to be upgraded or at least checked out before you can "get it on".