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Nitrous Jetting Chart

Old 10-09-2008, 09:22 PM
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Vehicle: 2001 Hyundai Tiburon

Everything Ive heard about a 75 shot is that you should get a 190 pump to back it up along with 2 step colder plugs. Then it should be fine. Havent actually done it though.
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Old 10-10-2008, 03:16 PM
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Vehicle: 2001 Hyundai Tiburon

QUOTE (JonGTR @ Oct 9 2008, 08:20 AM) <{POST_SNAPBACK}>
And how does the Zex kit magically know that you're leaning out? Does it include a wideband sensor? It increases fuel pressure, but without a wideband or O2 reading, it's not going to know you're running out of fuel.

The car naturally maintains it's own stoichometeric ratios. ZEX adds the proper amount of nitrous and fuel in metered dosages with it's own monitoring system. It's not magic, you add a certain amount of 33% oxygen, you need a certain amount of fuel to go with it. As long as fuel pressure is maintained above

QUOTE ( ZEX install manual)
The ZEX™ nitrous system’s injector nozzle is the most advanced nozzle design in the industry. The primary features are the fuel transfer tube and the self-adjusting properties of the design. The fuel transfer tube injects the enrichment fuel directly into the outer edge of the nitrous plume. This high- speed nitrous gas shears the fuel away from the tube, atomizing it to a much finer degree than other nozzle designs. This ensures perfect fuel distribution from cylinder to cylinder, especially with the higher horsepower settings. The fuel transfer tube also allows for a self-adjusting characteristic. Because a vacuum is created as the nitrous gas is being sprayed across the tube opening, as bottle pressure goes up, so does the gas speed and vacuum level. This increase in vacuum "pulls" more fuel out of the nozzle and ensures your tune-up will not go lean. This feature ensures much safer tune-ups.

How the ZEXâ„¢ Nitrous Oxide System works: The ZEXâ„¢ Part #82023 nitrous oxide
injection system begins with a connection to a supply cylinder containing pressurized
liquid nitrous oxide and a connection to the engine’s fuel system. These connections go
to the Nitrous Management Unit, which houses the nitrous and fuel solenoids.
These solenoids are normally closed, but are opened when the TPS switch senses that the
nitrous system is armed and the engine is at wide-open throttle. Once these solenoids
open, the nitrous and fuel are delivered to the nitrous nozzle via flexible delivery lines.
The amount of nitrous and fuel that is injected through the nozzle is adjustable by means
of metering jets installed in the nozzle itself. These metering jets allow for easy changes
in horsepower settings.
• How to adjust power levels: The ZEX™
nitrous kit is designed for multiple power
levels. These levels are controlled by metering
jets installed in the nozzle’s fuel and nitrous jet
fittings. To change the power output, all you
need to do is install the appropriate set of jets
as shown in Fig.1. The correct combination of
jets is listed on the tune-up sheet on the back of
this instruction manual.

As long as you are maintaining 36PSI or higher fuel pressure and you have placed the proper jets into the nozzle, the ZEX kit takes care of the rest. That's why I'd like to get a fuel pressure monitor gauge.

Engine Modifications:
The ZEXâ„¢ Nitrous System, out of the box, is designed to work as a bolt-on kit for stock or mildly modified vehicles. Mildly modified vehicles would include header upgrades, exhaust upgrades, air filter kits, etc. If major engine modifications have been performed, a fuel pump upgrade will be required for safe nitrous system operation. Major engine modifications would include turbochargers, superchargers, aftermarket cylinder heads, head porting, camshafts, intake manifolds, etc. Failure to upgrade the fuel system when using nitrous in these highly modified applications may cause serious lean conditions that can result in severe engine damage. Spark plugs & nitrous performance Quite often, a factory type wide-gap projected nose plug will produce a detonation condition after a few seconds of nitrous use. The detonation is not due to the heat range, it occurs because the ground strap of the spark plug becomes a glow plug instead of a spark plug. The ground strap is too long to dissipate the extra heat produced by a nitrous accelerated burn. The correct solution is to replace the plugs with units that have shorter ground straps. By doing this, you will shorten the heat path from the ground strap to the plug base. ZEXâ„¢ Hyperformanceâ„¢ spark plugs are recommended for many applications. This plug features three ground electrodes to ensure optimum spark energy and detonation resistance.

Reading Plugs & Tuning ZEXâ„¢
Nitrous Kit
Because the real limit of how much power you make with the ZEX™ Nitrous Kit is your car’s fuel system, you need to tune up to that limit. Start with the lowest power level nitrous jet and corresponding fuel metering jet. Make a full throttle pass at the drag strip and read the plugs. Not enough nitrous/too much fuel results in a sooty, black plug
coloration. This coloration means that the fuel mixture is too rich. Too much nitrous will exhibit high heat in the form of a bluish or rainbow-like coloring on the plug's metal surfaces. This means you're engine is about to, or is, detonating. If this is observed, ensure the proper spark plugs are installed, reduce nitrous/increase fuel delivery, and ensure the proper grade of fuel is being used. When you check the spark plugs, check EVERY plug. Don't just spot check the easiest plug you can access. Due to the wide possibility of air/fuel mixture variations, you need to check every single plug for signs of detonation or other problems. If your plugs indicate too much fuel, trim the fuel delivery down by installing a smaller metering jet. If you are too lean/not enough fuel, you need to install a larger metering jet to increase fuel delivery.

And that's how you decide what to use for a jet. I didn't see any discoloration on my plugs, they were clean. I just run 55 normally.
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