I took the time to write this post just for this forum, so if you're a troll please don't pollute this thread with your crap...unless you're an experienced troll with a suggestion, then I say post away, I'll update this post as needed with suggestions, grammar correction, etc.
Note: Nitrous is not for the faint of heart. You can take as many steps as possible to make it safe, and you can still tear something up. I don't suggest this install to a novice. I will go so far as to say that if you couldn't replace the head gasket in your car yourself or readily pay someone to do it, you shouldn't use nitrous. If your car isn't reliable and as close to perfect running condition as is possible, you shouldn't use nitrous. If your car has a lot of miles on it and it is your only mode of transportation, you shouldn't use nitrous. If your car is burning oil, nitrous will make it detonate violently more often than not...and you shouldn't use nitrous.
Caution: This install is for a 2004 3.5RL. Your ECU pinouts, wiring colors, and settings may vary.
When I set out to design and install this system, I had a few things in mind that influenced my choices:
1 - Minimum permanent modifications to the car.
2 - Minimum wiring through the firewall
3 - No extra switches for arming, etc.
4 - Stealth install. The car is still serviced at the dealership.
5 - Easy to remove.
6 - Idiot proof.
7 - Simple to disable. The nitrous controller is wired to a harness so that it can be easily removed from the system completely.
8 - Maximum safety. A conservative amount of nitrous with the proper amount of fuel under a variety of circumstances.
The system is activated at WOT when the RPMs are between 2400 and 5800RPM. I chose 2400RPM because the factory stall speed for the torque convertor is 2250rpm and I wanted to engage the nitrous above that point to help control wheelspin. I chose 5800rpm to stay off the 5900rpm redline and fuel cut. All wiring is done at the ECU. There is only 1 wire and the bottle feed line that runs through the firewall.
There is a concession to arm the nitrous system only if the traction control is off. There is a low current +5vdc output on the ECU. A small 5v reed (or electronic) relay can be used to interrupt the trigger wire to the primary relay. I may switch to arming the nitrous system by disabling the traction control only. Make sure your traction control is off when nitrous is engaged. The TCS system cuts fuel. Fuel cut is your enemy with nitrous involved. Burned sparkplugs to burned pistons can result.
I have also labeled the left and right bank 02 sensor wires, so that you can monitor 02 voltage while tuning. You should shoot for at least .88v (up to .95 is best but not all 02 sensors will generate this voltage regardless of the A/F ratio based on age and EGT). This is not an optimal method of tuning, but it is better than nothing.
ECU (PCM) LOCATION
SIDE VIEW OF ECU WITH WIRING DESCRIPTIONS
SOLENOID AND Digital RPM Two Stage Window Switch / TPS WIRING
ADDITIONAL DIAGRAM TO HELP IF YOU'RE UNPLUGGING THE HARNESSES FROM THE ECU
For my install I used twin 10lb bottles (* items you don't need for single bottle):
2 - 10lb nitrous bottles
2 - 10lb bottle brackets
1 - -4AN Tee Male Male and Swivel Female*
1 - -4AN SS second bottle to Tee line*
1 - -4AN SS bottle feed line*
1 - Cheater Nitrous Solenoid (1/4" NPT in and out)
1 - 1/4"NPT Male to -4AN Male
1 - 1/4"NPT Male to 1/8"NPT Female
1 - 1/8" NPT TEE 2 Male, 1 Female
1 - Nitrous Pressure Regulator 15850NOS
1 - 1/8” NPT x 3/16” Hose Barb
1 - 1/8" NPT Female to Female 90 degree
1 - 1/8" NPT to -3AN Male
1 - -3AN SS nitrous nozzle feed line
1 - Blue NOS fan spray nozzle 13500NOS
1 - Nitrous Nozzle Bulkhead Fitting
1 - Discontinued 17538NOS Vacuum TEE with changeable jets.
1 - DynoTune Nitrous Digital RPM Two Stage Window Switch / TPS
1 - .035 Nitrous Jet 55hp, .042 Nitrous Tee Jet (Recently installed .038 nitrous jet 65hp still quite rich, then .040 jet ~73hp pretty close to perfect a/f)
2 - 5 wire automotive relay 30A
1 - 10A fuse and fuseholder
Assorted wire, electrical connectors, etc.
Initially I had a diode isolated relay wired to engage the system only when the car was in D3. Not only does this limit the speed at which I could activate the nitrous, but a diode fried today and pissed the ECU off royally. I therefore do not suggest using the D3 arming method.
I suggest testing all the components of your nitrous system prior to installation on the car. Pressure test the solenoid(s) and check for leakage. Make sure the SS braided lines and AN fittings do not leak. A 3-AN block off cap comes in handy if you want to mock up the entire system and pressure test it. By far the most important thing to do is secure the rubber vacuum lines on the fuel side of the kit. If you blow off a hose here, you'll lose all your extra fuel and that's bad.
Blow by blow installation instructions.
1. Remove Front Interior Trim Panels
a. Passenger Side Front Rocker Trim - 4 Clips, pop out, straight up.
b. Passenger Side Front Kick Panel - 2 Clips, pop out, towards center dash, hook located at front edge of panel (important for proper refitting)
c. Passenger Side Lower Dash Cover - 3 Clips, pop out, straight down towards floor, 3 hooks located at front edge of panel (important for proper refitting)
2. Removing Rear Trim and Seat Bottom.
a. Passenger Side Rear Rocker Trim - 3 Clips, pop out, straight up.
b. Open Both Doors. Reach under the front edge of the backseat. You'll have to feel for a little pull tab, which when you pull toward the front of the car and lift up on the seat, it will come loose. You have to do this on both sides. The tabs are located under the front edge about 1/3 the distance from the edge of the total length of the seat. You'll have to pivot the front edge of the seat upwards to pull it loose because it has two metal loops that go behind the rear seat back.
c. Snake the -4AN line from the trunk through the rear seat bulkhead to the floorpan under the rear seat.
I chose not to run colder spark plugs, and I burned up the factory platinum plugs after increasing the nitrous. Nothing bad happened, just fuel mileage went down to about 12mpg. Copper core plugs are suggested for nitrous applications. I switched over to NGK BKR7E-11 plugs, stock number 1283. This plug is two heat ranges colder than the factory plug. I also reduced the gap to .035".
An important note for plugs and nitrous. You generally want to run a tighter gap, factory plugs are gapped at .043in, I would run .035 max. In some cars I've run down to .025. If you do change the plugs, make sure to apply a small amount of anti-seize compound, hand tighten them, and torque them to 13ft/lbs. It is easy to change the spark plugs. You need a 10mm socket (to remove the engine cover, 2 nuts and 1 bolt on top and two bolts under the front edge) and ratchet, a 12mm socket (to remove the engine brace, 2 bolts at the firewall and 2 nuts at each shock tower, retorque to 16lb-ft) , an 8mm socket (each coil is secured by two 8mm bolts) and ratchet, a torque wrench, and a spark plug socket.
If you have your choice of nitrous systems, I would purchase a NOS Dry Single Fogger kit such as PN 05122NOS. The only downside to purchasing a new kit is that they come with a fixed orifice vacuum pressure tee PN 17538-42-SNOS which has a set .042 bypass jet built in (NOS also has a 17538-59-SNOS which has a set .059 bypass jet). The older kits such as the original dry mustang kit had a vacuum pressure tee with jets you could change yourself for fine tuning (such as I have). Sadly unless you get lucky on eBay you won't find one. Whatever kit you choose or if you decide to build your own from parts make sure you have the nitrous pressure regulator PN 15850NOS.