Basic N2O q's

[IPT]

OK

I have some basic questions..

On a dry kit, the extra fuel is suppled thru the stock injectors. How well does that work with larger injectors and a fuel control device like an AFC?

On a wet kit, were do you tap into for the fuel to the fuel silnoid?

Hoe do you "tune" the kits?? How do you figure out how much N2O and fuel to add??

I have a pms unit that has separate fuel and timing maps for N2O. Can I just use a dry kit and add the extra fuel through the injectors w/o a sky high fuel rail pressure? (650cc injectors)

I have some more let's just start there..

Thanks

 

[rdrkt]

I would not suggest running a dry kit. Its rare that people have big enough injector that they can run nitrous and not run out of fuel. Most people run around 85%+ duty cycle normally and that just isnt enough fuel.

As for tuning usually you turn down the boost a few lbs and then run a small shot while logging or using a wideband then gradually start raising the boost.

The PMS unt you are using will be a problem if you ever get a real turbo. My unit was overrunning the maf provided at a very low rpm/boost level. You will more than likely need a recalibrated maf. However I still ran faster and more consistently on a hacked mas and safc then I ever did with the PMS.

 

[IPT]

The MAF has been calibrated for the higher air flow.

 

[larryd]

so what is the ideal kit for the Eclipse?

 

[dsmtrance]

I myself have been wondering about this (nitrous) as well. Once I put in a VPC, some HKS cams, and replace my leaking HG I am planning on adding a 50 shot to top it all off. These are some of the same questions I had.

 

[NosLaser]

<<<On a dry kit, the extra fuel is suppled thru the stock injectors. How well does that work with larger injectors and a fuel control device like an AFC?>>>

A dry kit adds fuel by spraying a controlled amount of nitrous into the fuel pressure regulator's pressure source, thus bumping fuel pressure in the same manner boost adds fuel pressure. I had good luck with a dry kit on 660's, -8 fuel line, Walbro 255LPH HP, adjustable FPR, an AFC, running about 60psi at idle. I would highly recommend staying away from a dry kit on a turbo car. I tried it and had good luck with it, but that surely doesn't mean everyone will have the same success I did.

<<<On a wet kit, were do you tap into for the fuel to the fuel silnoid?>>>

Basically, you tap fuel from the fuel feed line. There are a few ways to do this. The EASIEST/cheapest way is to simply buy a brass or stainless T tap with two barbed ends on it, and a -4 male AN fitting on the third end. You cut your factory rubber fuel feed line after the fuel filter, slide the barbed ends into the respective fuel feed line(s), and thread the nitrous line on to the AN fitting. You would need to get these fittings from a hydraulic supple store such as Aeroquip for instance. Obviously, make sure you use high pressure clamps on the fuel feed ends that you have just cut. The other way to do it is a bit cleaner, and that is to purchase the fuel pressure gauge kit from B&M, and use their NPT fitting. Then you must buy a fitting from there that also has a -4 AN for which to thread the nitrous line to, which could be a screw on affair if you luck out, but will most likely end up being a weld-on affair. This way is harder, a bit more expensive, and doesn't have any advantages other than it looks more like a factory install.

<<<Hoe do you "tune" the kits?? How do you figure out how much N2O and fuel to add?? >>>

First off, I ain't no hoe. Basically, tuning a nitrous kit is much like tuning anything else. Nitrous, however, has it's advantages. The primary advantage is that nitrous will add fuel on it's own. All you have to do is size the kit properly; and all that means is start off small, and work your way up. You don't go out and buy a FP Green and run 28 pounds of boost. You start at 15 pounds, and work your way up. Same principle applies here. If you are using a wet kit, start off with a 50 shot. With a dry kit, I'd say start at 40 or 50, and go up from there. For a wet kit, a 50 shot on our cars is a 22 fuel jet, a 37 nitrous jet. A dry kit, I honestly don't remember the jet sizes as it has been a bit too long. Remember, the dry kit has provisions for extra fuel through bumping fuel pressure, and a wet kit has provisions for extra fuel by almost adding a 5th 'injector.' Nitrous is actually quite user friendly. After you spray the car for the first time, just make sure you monitor your gauges, and begin tuning from there. (I highly recommend changing your oil to full synthetic as nitrous will shock the motor, and you want to make sure you have good clean fresh oil, running BPR7ES plugs gapped at .028 to start with as it may want to blow the spark out on higher gapped plugs, run some good gas just as a safety precaution, and put your boost back to STOCK. When you spray even on 10 pounds of boost, it's going up to 20. Trust me.) Start off by adding/subtracting fuel via your engine management system, be it a PMS, AFC, or what have you. You can also add/subtract fuel directly through the jets by re-sizing them. On a wet kit, the bigger the jet, the richer the car runs. On a dry kit, the bigger the jet, the leaner it runs. Another important thing is nozzle placement. With a dry kit, you simply have a cloud of nitrous to carry, which is very light. You can take advantage of that by giving it a longer path of travel to atomize. Think of it as throwing a punch. Which do you think will make more power, punching someone with your arm already extended halfway, or cocking it back and letting loose? Same principle here. Plumb the nitrous nozzle on a dry kit right after the BOV. Give it time to atomize. On a wet kit, you have the opposite force working here. Yes, you carry light nitrous oxide, but you also have to carry heavier fuel as well, and keep them in the same "cloud." If you plumb that right after the BOV, what do you think will happen? The nitrous will have time to travel much faster than the fuel, and you will create a lean condition, and also run the risk of fuel puddling in the upper IC pipe and causing an explosion of the bad kind. Plumb the wet kit into the TB elbow as close to the TB as you can so it has a straight shot right into your intake manifold.

<<<I have a pms unit that has separate fuel and timing maps for N2O. Can I just use a dry kit and add the extra fuel through the injectors w/o a sky high fuel rail pressure? (650cc injectors)>>>

Nope. Not with a dry kit. Use a wet kit. It's much safer, and will flat out make more power. The dry kit on my Laser hit pretty hard. The wet kit I just installed on my Talon (oops, did I say that out loud??) hits WAYYYY harder than the Laser. A wet kit hits HARD. Let's just say, a wet kit starts making torque yesterday, and keeps making it till tomorrow. Use a wet kit, and your little high revving 4 banger turbo car will spool-up/rev up quicker than a big block Chevy. (Now imagine if you will, a turbocharged/nitrous'ed Big Block Chevy. That's man land.)


I hope I have answered your questions, and if you have any more, fire away. Nitrous class will resume later.

Regards,

 

[IPT]

Now what to do about timing?? Did you have any way of watching what your timing curve looked like when you are spraying?? On the PMS would it be a good idea to pull some timing or just go hog wild and give it all she has got. (on race gas)

How will the size of the shot differ from the pump gas to race gas?? What did you do different when switching fuels??

 

[Silent2g]

do not put a dry kit on a turbo car, the fuel pressure is already high enough.

a single fogger wet kit seems to be the ideal way to go on these things
glazer, rau. and buschar seem to like it

 

[NosLaser]

<<<Now what to do about timing?? Did you have any way of watching what your timing curve looked like when you are spraying?? On the PMS would it be a good idea to pull some timing or just go hog wild and give it all she has got. (on race gas)>>>

Ideally, you want to be able to go all out, but it doesn't always work that way. I used to run 33 degrees of timing at 7K rpm with 20 pounds of boost and an 80 shot dry. Will that work for everyone? NOPE. You have to start off conservative, and work your way up from there. If you advance the timing, what you are going to worry about is when you reach peak cylinder pressure. If you reach peak cylinder pressure at or about TDC, the rod/piston combo must be strong enough to handle the possibility of the crank not spinning fast enough to keep up. This is hard to explain. If you need me to explain this more, let me know. Bottom line is as muh timing as your motor can handle without breaking a rod or crossing the threshold of detonation, the more power you will make.

<<<How will the size of the shot differ from the pump gas to race gas?? What did you do different when switching fuels??>>>

I personally ran the same shot on pump and race gas. The ECU will control timing enough to not blow the motor in most cases, however for safety's sake, I recommend spraying only on race gas. If you are spraying, you are racing, and why not run race gas, right?