Tony,

Got a few wet NOS questions for ya. I have a tuner here in Cincy that offering to do a 60 shot wet install for just under $900. Does this seem reasonable?

Is wet that much 'safer' than a NOS 5123 dry kit which some guy is offering to install for $250.

Thanks for your help and btw your setup looks tight.

 

What kind of wet kit? Is it a single nozzle wet kit from Nitrous Express (NX)? Direct port like mine? Custom plate system? If it's $900 for installation on a direct port kit. The price is reasonable.

Wet is safer because it doesn't depend on your OEM fuel pressure regulator and your OEM injectors for fuel. You might max out your regulator or injectors. With wet kit out of the box, the nitrous jets and fuel jets are perfect match. You want more nitous on a wet kit. Pop in a bigger nitrous jet and add the corresponding fuel jet. You are good to go. Don't have to worry about your fuel pressure regulator and your OEM injectors.

 

I believe it was a NOS Direct Port but I'll find out more tomorrow. What shot are you currently running?

 

80shot right now.

 

Yo max2nv, turn on your aim so i can im you .. lates, check your maxima.org fan mail.. hehe if you get this im at nizmolee

 

Tony,

beside the NOS kit itself I noticed you have other related mods such as the gauges and new fuel pump. With your 80 shot which of these items are necessary and which ones are just'useful'.

I am trying to get estimate a more solid $ amount by including every 'needed' item and them deciding on other as affordable.

 

Now go out and get you some...

The most common and least expensive Nitrous option for the Maxima is the Nitrous Oxide Systems Universal EFI Dry manifold kit #5124. Cost for the kit is around ~$550. This kit will supply a maximum recommended 70 hp gain from a .036 nitrous jet. It’s not a Maxima specific kit, but it does work on the Maxima.

The dry kits comes with a 10lb bottle with a nitrous pressure gauge, two small (Power Shot) nitrous solenoids with a mounting bracket, 14 ft braided line, one short braided line, one fan spray nozzle, one "TEE" fitting, one nitrous pressure regulator, flare jets, a fuel pressure safety switch, a micro switch, an arming switch, bottle brackets, some fittings, and some electrical stuff and an instruction manual. You will need a hose barb “T” fitting and some extra EFI fuel hose, so plan on making at least one trip to the auto parts store. If you are mechanically inclined and have some experience working on automobiles it shouldn’t be a problem to install this kit in an afternoon.

Nitrous is injected into the motor through a fan spray nozzle located in the air intake path just before the throttle body. The extra fuel is supplied through the factory fuel injectors. This is accomplished by raising the fuel pressure from the normal wide-open throttle (WOT) pressure of 43psi to ~60psi when the NOS is engaged.

NOS claims that your stock plugs are fine if you use the kit as directed. However most NOS users believe that you should use colder spark plugs. I use NGK PFR6B-11 these are one step colder than the factory plugs on the Maxima, they are the stock plugs for the NA 300ZX (Thanks Don in TX!!!) Also for every 50 hp that you add you should decrease the plug gap by .004. If you add 60hp over stock you should decrease the gap .005. You have to account for all the power that you have added, not just what you've added with NOS. So if you've added 40 NA hp and 60 NOS hp you would decrease the gap by .008.

NOS claims that your stock ignition timing is ok if you use the kit as directed. However most NOS users recommend that you retard the ignition timing 2 degrees per 50hp. The only way to do this on the Maxima as of this writing is by using the JWT NOS ECU Daughter board. Its ~$900 and only available for the 95 & 96 years of the 4th gens, and I think for the 3rd gens also. JWT also controls the fuel flow for NOS runs. It’s the way to go if you have the $$$. However to increase the power level you must send your computer back to JWT to be reprogrammed.

There are plenty of opinions on this; the bottle pressure should be between 900 & 1000 psi or a temperature of 75-85 deg F.

The bottle holds 10 lbs of nitrous and needs to be refilled when there is under ~3 lbs left, cost is usually ~$3 - $3.50 per lb of NOS

You'll have no trouble with running 92 octane or higher.

Here are some other very nice but not necessary items...

An EGT Gauge is a great way to monitor what’s going on inside your motor. If the temps rise higher than 800 deg C your motor is running too hot and you need to investigate why. Basically a rich mixture will show as a lower temp, a lean mixture will show as a high temperature.

An A/F ratio Gauge is just as helpful as an EGT for monitoring what’s going on inside of your motor. A rich mixture is better than a lean mixture wile running NOS. If your motor shows lean you need to investigate why.

A fuel pressure gauge is needed if you plan on going higher than 70 hp with the NOS EFI Dry kit. If you stay at or below the 70 hp level the fuel pressure safety switch that comes in the kit should be all you need. The switch does not come adjusted fro the factory. You do need to adjust it. If your budget will allow, I recommend a cockpit mounted fuel pressure gauge. This is due to the issue of the strength of the stock 4th Gen fuel pump. If you are having a problem it will let you know before you have problems.

A window switch is used to control when the NOS is turned on and off. It operates of engine RPM's. You can set it to turn on and off at particular RPM's. I have mine set to turn on at 3500rpm's and off at 6200rpm's. It prevents the NOS from coming on at too low of an RPM or staying on when you hit the rev limiter. Basically if you hit the factory rev limiter while running NOS the fuel pressure will cut and bye bye motor. Only 5spd cars need worry about this. An auto will shift to the next gear. Or if the system engages at too low of an rpm, under ~2500rpm, bye bye motor. The low limit on the window switch is also useful when launching a 5spd. Most people launch their Max's at ~1800rpms. They have trouble controlling wheel spin with the normal horsepower. If you add NOS right when you launch your spinning your wheels for sure. So the window switch will allow you to launch with out the NOS up until you hit the window, 3500rpms on my set up. You could also power shift with the NOS using a window switch. But I don’t think the Maxima tranney could take it.

A bottle heater (preferable the NX model since it is pressure actuated instead of temperature or manually actuated and much more powerful than the other brands to boot.) I have the NOS version and it works just fine. It’s half the price of the NX version.

A remote bottle opener is great for street use since you can turn the bottle on from the driver's seat. The NOS brand is a heavy-duty solenoid that attached to the bottle directly or is put inline away from the bottle. The NX opener is a literal bottler opener. It actually turns the bottle valve when you flip the switch.

A purge kit makes for quite an intimidating show but if you want to save a little money you can get the same effect as a purge kit if you hit the spray briefly during your burnout. A second or so is all it takes. With a dry kit it just doesn't hit quite as hard with air in the line, which can be a very desirable thing if traction is a problem. You might just leave that air in the line if this is the case. Hello FWD.

see next post

 

Ok, you've got your kit installed. Now what? Let's check to see if it will fire. With the bottle off, arm the system and have someone push the pedal to the floor. Does the WOT switch get tripped? Do you hear and feel the noid's click on and then off again when the pedal is released? If you have a FPSS you'll have to bypass it to get the 'noids to click with the engine off by connecting the wires to it together. Just screw them both to the same post of the switch. Ok, disarm it and open the bottle. Check for leaks.

I recommend using a push button switch, either in place of or in conjunction with the NOS arming switch. This will allow more control over when the system is engaged. I have a small push button switch that I hold in my hand or strap to the shifter. When I am running the nitrous I can choose to engage it when I need it. If I am racing another car on the street I can use it if I need it. I can hit it in second and if I’m far enough ahead I won’t use it in third. At the drag strip I will just hold it down and let the WOT and window switch control the system.

Approximate HP values for single NOS Jets
HP NOS Jet
25 .024
30 .026
35 .028
40 .030
50 .032
60 .034
70 .036

I recommend you start with a ~50hp shot, .032 nitrous jet, and work your way up. This is because the stock fuel pump may not be able to support the fuel needs of the 70hp shot.

When you first make your test runs you need to check your spark plugs. If you see metallic specs (looks like pepper) on the white insulator part of the plugs your motor is detonating. Or if the ground strap on the spark plug looks like its anodized blue all the way up to the plug threads you are too lean. Adjust you system to compensate.

If you have engine mods other than NOS you many need to decrease the NOS hp level because you are approaching the limits of flow of the factory fuel pump. I put the NOS kit on my stock motor and it worked fine at 60hp. When I added my CAI and Y-Pipe my plugs showed that I was running a little lean. Others have not had this problem, perhaps I had a weak fuel pump or I’m too **** about leanness (is this a bad thing when running NOS?). I then went down to a 40 hp shot and the leanness went away. Of course I wanted the full 60 hp shot back so I then upgraded to a bigger fuel pump and an adjustable FPR. This did the trick, no leanness at 60 hp.

I use a Walbro GSS342 255 Liter Per Hour (LPH) High Pressure pump. Walbro makes 3 versions of the pump. A 190lph which is a good stock upgrade or replacment, a 255lph which would be good for a high volume stock pressure set up like a wet nitrous set up, and 255lph HP which will flow 38gph@100psi, this is useful for modified dry nitrous set up's like mine, I run ~85psi of fuel pressure. The two smaller pumps can’t support the flow needed at extremely high pressures. However, both the standard Walbro pressure pumps will support a dry kit that runs 70psi and under. Running at 70psi you should be able to use a .042-.044 nitrous jet. If you start playing with the jets in the NOS dry kit I recommend you get cockpit mounted fuel pressure gauge.

I don’t claim to be the know all on NOS but I have used it for a wile on a few vehicles. If you are unsure about something take your time and ask around. Please follow the directions included in your kit. The NOS web site and technical assistance phone line are great resources for information on using nitrous. Play it safe and you’ll get many miles of fun out of your NOS kit. If you get greedy for hp or careless you can blow your motor very quickly.

I have the instruction manual scanned in if you would like a copy just e-mail me.

Thanks to our own “Don in TX” for helping me understand some of the Maxima specific issues for NOS use and “The Colonel” from the LS1 site.

Matt Pelto
MardiGrasMax
matchou@home.com

mp 1/01

 

MardiGrasMax:

Thanks for the heads-up.
I have already read that article from the clubmaxima.com site, it was very informative and well written.

Even though jcwhitney.com has the 60 shot dry kit(NOS 5123?) for $375 delivered, I am being charged $250 for installation, then I need a new fuel pump, and with the needed electronic gauges it would total to a lot more that a 70 shot wet kit installed so I am researching the total cost for pursuing that route also.

 

A pro fogger set up done right will be $$$. I bet that the shop you are talking to is selling you a single fogger wet system. This is not a good idea on a VQ because the intake runners are designed to flow air not liquid, their shape is also not straight, the turn from the throttle body to the intake runners is very bad for a single fogger wet system. You will get uneven distribution, causing some cylinders to run leaner, and some to run richer. This probably will lead to engine damage and uneven wear in the piston rings.

The best way to do a single fogger is through the dry kit. My advice is get the kit and set it up at 50hp. Check your plugs for signs of leanness. Then you will know what you need to do to get to your goal of 70hp. You may have a strong fuel pump that will hold the pressure. Or you may need to change it out. You can do the nitrous with out the bells and wistles, but it will take time and patience to tune it. You'll get sick of taking the plugs out to check them...

 

There are tons of accessories and $$$ can add up pretty quick. The bare minimum I would get besides the basic kit is an EGT gauge ~$200, fuel pressure gauge $80 and a new fuel pump $100. Other stuff just makes the system perform better, but not really needed.