A wet system injects the nitrous with added fuel to the mixture after the MAF. A dry system just puts the nitrous in before the MAF and lets the pcm add more fuel.

 

A dry system injects only nitrous into the intake tube and the extra fuel is introduced threw the factory pcm and injectors, A wet kit injects nitrous and fuel into the intake tube.

 

**** I took to long typing it.

 

2k4Squirrel, If you look at the top of the picture you can just make out the solinods. There are 2 on each side with this setup. I made a plate, which you can also just see, and mounted the 'noids inverted from it. With the engine covers on, you cannot see a thing, looks completly stock.