ZEX dry nitrous system

[jako92]

i just bought a ZEX dry kit and it says it has active fuel controll which adds or subtracts enrichment fuel. how does it add and subtract fuel if its a dry kit?

[JoeEvert]

Jako,

There are two types of systems; wet or dry. In a wet system you are injecting fuel into the air intake stream with the nitrous. This requires you to tap into the fuel system and plumb the fuel line to the nitrous nozzle. In a dry system the additional fuel required for nitrous is usually supplied by the existing fuel injectors by increasing the fuel pressure at the fuel injectors when nitrous is being injected. This is usually done by providing pressure to the top of the fuel pressure regulator which clamps down on the fuel return line. I think the Zex system compensates for low bottle pressures and adjust the fuel pressure accordingly thus it is "active" fuel control.

HTH

Joe

[srsnow]

Basically they are using Bernoulli's principle to control the pressure signal to the FPR. There is a measured orifice inside the control box and the idea is that the pressure drop across this orifice will stay relatively proportionate to the pressure of the nitrous. So that as the bottle pressure drops so does the output pressure to the FPR. It is an interesting idea but in practice I am not sure how well it works.

[flames4me]

what they said^

dry increases fuel pressure to the injectors
wet injects additional fuel at the same spot as the nitrous is injected at

both ways has the same basic outcome, just differant ways of getting there.