Problem with zex plate upgrade on bigshot system

[wkd-windza]

Hi, I upgraded my N.O.S bigshot system with a zex plate. When wide open throttle the fuel gauge supplying enrichment fuel goes from 6 psi tp 'off' the dial. Is it possible that nitrous is going straight thru to the fuel side? Also, i installed the AN fittings from the N.O.S bigshot plate onto the zex plate so it will accept N.O.S jets, is this ok?

Thanks

[iwannagofaster]

The swapping of the jet holders is fine. The fuel pressure on the other hand, is very unusual. The only way we will know for sure is to pull the plate off, remove the fuel side feed line and jet, and spray it to see if anything gets out of the fuel side. At that point, we will be able to diagnose it further.

[wkd-windza]

Nitrous came out the fuel side when fuel line removed and activated. Ive had 2 bits of advice from nos racers.One said i can use the AN fittings from the N.O.S plate so i can use N.O.S jets as zex jets hard to find here in Aus and another said i must use zex jets because of the different flowing capabilities.

We run a 225 shot with the N.O.S system, what zex jets do we use for a 225 shot?

Thanks

[iwannagofaster]

You can change the jet holders, that is no problem. Do you have the conversion chart for the jetting on our plate? We have a chart for NOS jetting on our plate. You can also use Nitrous Works or Nitrous express jets in our holders if those are easier to find (they use the same jets that we do). I am looking for a part number for the seperator gasket and I will let you know.

Jetting For ZEX™ Perimeter Injection Plate
Read over this recommended jetting chart completely before attempting to install and use your ZEX™ Perimeter
Injection Plate. Failure to do so may result in damage to your engine from improper jet selection for the nitrous
injection hardware you have. This jet list has been compiled directly from information distributed by the listed
nitrous system manufacturers. The timing retard recommendations are general and can vary from application to
application. ZEX™ does not guarantee these jet or timing settings, they are provided as a tuning guideline for
the end user when converting to a ZEX™ Perimeter Injection Plate. ZEX™ is not responsible for damage or
injuries caused by improper use of, or tuning of, this plate.
It is very important to reference the recommended jet charts that came with your original nitrous system. The
nitrous plate is not the primary restriction in a plate nitrous system; it is the tuning jets, solenoids, delivery lines,
and nitrous cylinder valve. How these components interact is what generally determines the overall nitrous and
fuel flow. Manufacturers develop their jet charts with these components in mind. The important thing to
remember is to begin the tuning process with jet sizes that correspond to what your original plate system came
with.
A WORD ABOUT JETS:
• ZEX™, Nitrous Express™, Nitrous Works™, and Compucar™ all use jets that are dimensionally very
similar and can be used interchangeably.
• NOS® and Edelbrock® use jets that are dimensionally different from ZEX™ compatible jets and cannot
be used with the jet holder fittings on the ZEX™ Perimeter Plate. If converting your NOS® or
Edelbrock® plate system to the ZEX™ Perimeter Plate, you can simply swap out the ZEX plate’s jet
fittings for the ones already installed in your existing NOS® or Edelbrock® plate. Doing this will allow
you to use your existing jets that originally came with your non-ZEX nitrous system.
Nitrous Oxide Systems®:
If using a ZEX™ Perimeter Plate with the #05101 Super Power Shot System, start with this recommended jetting:
100hp 125hp 150hp 175hp
Nitrous Jet (900psi) 47 55 63 73
Fuel Jet (5.5-6psi) 53 61 71 82
Ignition Retard (deg.) 0-2 2-4 4-6 6-8
If using a ZEX™ Perimeter Plate with the #02001 Cheater System, start with this recommended jetting:
100hp 125hp 150hp 180hp 210hp 250hp
Nitrous Jet (900psi) 47 55 63 73 82 93
Fuel Jet (5.5-6psi) 53 61 71 82 91 102
Ignition Retard (deg.) 2-4 2-4 4-6 4-6 6-8 8-10
If using a ZEX™ Perimeter Plate with the #02101 Big Shot System, start with this recommended jetting:
175hp 225hp 275hp 325hp 350+hp
Nitrous Jet (900psi) 73 82 93 102 120
Fuel Jet (5.5-6psi) 82 91 102 110 116
Ignition Retard (deg.) 4-6 6-8 8-10 10-12 12+
ZEX™ * 3418 Democrat Rd. * Memphis, TN 38118
ZEXTEK™: 1-888-817-1008 * Fax: 901-375-3430
Revised 8/11/09
Compucar™:
If using a ZEX™ Perimeter Plate with the part #550100 Plate System, start with this recommended jetting:
50hp 125hp 175hp 225hp 275hp
Nitrous Jet (1000psi) 39 52 62 73 81
Fuel Jet (4.5psi) 39 52 59 70 78
Ignition Retard (deg.) 2 5 7 9 11
Edelbrock®:
If using a ZEX™ Perimeter Plate with the #70001 Performer Plate System, start with this recommended jetting:
50hp 75hp 100hp
Nitrous Jet (950psi) 38 46 57
Fuel Jet (6psi) 46 53 65
Ignition Retard (deg.) 2 3 4
If using a ZEX™ Perimeter Plate with the #70050 Performer RPM Plate System, start with this recommended jetting:
100hp 150hp 175hp 200hp 250hp
Nitrous Jet (950psi) 55 71 78 85 99
Fuel Jet (6psi) 61 75 82 89 102
Ignition Retard (deg.) 4 6 7 8 10
Nitrous Express™:
If using a ZEX™ Perimeter Plate with the #40040 or #40041 Hitman Plate System, start with this recommended jetting:
50hp 100hp 150hp 200hp
Nitrous Jet (1000psi) 35 41 57 70
Fuel Jet (6psi) 31 35 46 57
Ignition Retard (deg.) 2 4 6 8
If using a ZEX™ Perimeter Plate with the #30040 Stage 6 Plate System, start with this recommended jetting:
50hp 100hp 150hp 200hp 250hp 300hp
Nitrous Jet (1000psi) 41 57 79 82 88 136
Fuel Jet (6psi) 35 46 62 70 78 136
Ignition Retard (deg.) 2 4 6 8 10 12
If using a ZEX™ Perimeter Plate with the #50040 Pro Power Plate System, start with this recommended jetting:
100hp 200hp 300hp 400hp 500hp
Nitrous Jet (1000psi) 57 70 82 110 136
Fuel Jet (6psi) 52 67 82 110 136
Ignition Retard (deg.) 4 8 12 16 20
Nitrous Works™:
If using a ZEX™ Perimeter Plate with the part #10010 Single Stage Plate System, start with this recommended jetting:
75hp 125hp 150hp 200hp
Nitrous Jet (900psi) 46 62 73 81
Fuel Jet (6-8psi) 40 56 63 78
Ignition Retard (deg.) 3 5 6 8
If using a ZEX™ Perimeter Plate with the part #11010 Single Stage Plate System or #11020 Sportsman Plate System, start with this
recommended jetting:
125hp 175hp 250hp 300hp
Nitrous Jet (900psi) 62 73 93 120
Fuel Jet (6-8psi) 43 52 85 110
Ignition Retard (deg.) 5 7 10 12
If using a ZEX™ Perimeter Plate with the part #12010 Single Stage Plate System, start with this recommended jetting:
150hp 250hp 350hp 400hp
Nitrous Jet (900psi) 62 82 120 136
Fuel Jet (6-8psi) 52 63 93 110
Ignition Retard (deg.) 6 10 14 16
ZEX154, revised 3/8/09

[wkd-windza]

thats exactly what ive done... put in NOS fittings to take NOS jets 82 and 91. Gasket looks fine. Still not sure whats wrong but a guy over here said due to flowing differences between kits Zex jets must be used.. nothing making sense!

[wkd-windza]

Got some nitrous express jets and reinstalled zex fittings. All working fine now fuel pressure steady at 6 psi when activated.

[iwannagofaster]

Wow, I have never run into this before. I have a few customers that run the NOS fittings and have never seen this problem. Nevertheless, I am glad the issue is resolved and let me know if you need anything in the future. Thanks,