ZEX Appeal

There are 2 major types of nitrous systems, wet and dry. A fuel injected dry manifold system uses a spray nozzle to deliver only nitrous oxide to the intake. A wet manifold system introduces fuel and nitrous into the intake manifold. With a dry manifold system, the addition fuel is supplied by increasing fuel delivery from the injectors when the nitrous system is activated. It is called a dry manifold system because there isn't any fuel present in the intake manifold. The ZEX Nitrous System is a dry system.

ZEX designed this to be a complete bolt on kit for a stock Mustang that will require no additional modifications, but because of the increased airflow from aftermarket heads and an intake there will need to be some upgrading of the fuel system. My car already has 30# injectors with a 155 lph fuel pump. The 155 lph fuel pump is not enough to feed the engine at higher RPM's. So a 255 high flow pump was ordered and installed. For this we contacted Dave at JD's Performance in Florida for his expertise in the Mustang community. He supplied us with a Walbro 255 high flow fuel pump at a great price to feed the fuel into the engine. JD's has always been our first choice for parts because of his service and prices.

One thing that I like about the ZEX kit is how it works. Most current nitrous system use a throttle arm actuated micro-switch. That means you have to fabricate a mounting bracket for the switch and adjust the placement of the switch to get it to work properly. The ZEX kit utilizes a wire that you simply clip on the throttle position sensor (TPS) output voltage wire. The TPS voltage signal is sent to an electronic switch that engages and disengages the system at a predetermined voltage threshold. Above the threshold determined for wide-open throttle, the system activates. Below the voltage threshold, it remains dormant. The whole process begins with the supply cylinder containing pressurized nitrous. This cylinder is connected by means of a delivery hose to a normally closed electric switch. This solenoid valve, which is attached to a manifold assembly, is engaged and disengaged via the TPS switch. The manifold assembly distributes the nitrous oxide to the engines air inlet and the kit's supplemental fuel control circuit. The nitrous oxide that is delivered to the engines air inlet is conveyed via a delivery hose to an injection nozzle. The amount of nitrous oxide, which provides the oxygen required for the horsepower increase, is adjustable by means of a metering jet installed in the injection nozzle itself. The nitrous oxide that is distributed to the fuel control circuit passes through a small bleed orifice. This bleed orifice provides a reference source of bottle pressure and a controllable source of pressure to perform the needed function of fuel enrichment. Fuel enrichment occurs by conveying this source of pressure through a delivery hose to a vacuum ported fuel pressure regulator (FPR). This source of pressure on the rubber diaphragm of the FPR causes an increase in fuel pressure. This increase in fuel pressure performs the function of adding fuel volume through the engines own injectors. The amount of additional fuel that is added can be changed by an adjustable metering jet in the fue l control circuit. This jet accomplishes the task by controlling the amount of pressure allowed to build in the delivery hose to the FPR. The jet bleeds off excess pressure in the fuel control circuit and vents it through a delivery tube, back to the intake manifold plenum. All of this sounds very technical but it is unique to the ZEX system and is accomplished in a split second fulfilling their clams of a smart system.