Theres so much misinformation on this basic topic. I would like to clear up all the "Dry hits harder" "wet doesnt make the same power" "I know you dont want dry" misguided posts.

A "Wet" nitrous system is a system designed to add the fuel enrichment for the nitrous Via the system itself using a fuel solenoid. This is the only pre-requisite for a system being called a wet system.

A "Dry" nitrous system is just the opposite. A nitrous system that controls only the nitrous delivery. Most dry system rely on the factory injectors supplying the fuel for the nitrous demands.

That is all that determines dry or wet. Here's a little more in depth on them.

To get the target AFR with a wet system, you simply increase or decrease the fuel jet in the system. So for example, The car is running to rich on nitrous ( which you should know from reading the plugs ) then you could go a size smaller on the fuel jet to lean it out some. Or vice versa if the car was lean.

On a dry system, there are more ways to spray the system than wet. You can spray it post or pre MAF. If you spray before the maf you let the maf account for the added nitrous and it will provide fueling. Now this use to be common practice, but it is now being revised as fuel injection and tuning software becomes better and more available. If you spray nitrous after the maf, you adjust for this via a trigger of some sort. Different platforms have many ways of doing this. Some people wire a relay to the IAT sensor and make fueling adjustments their, some can run a wire powered by the arming switch to ecm or piggyback. Again their are many ways to go about this depending on the platform.

Pulling timing is the same for both wet and dry. This needs to be done via the tune or a auxiliary timing tuner.