The main reason this happened is that the nitrous kit was installed incorrectly, dont take this the wrong way. I'm sure that you did a very clean and professional leak-free install on your car. But this is exactly what happened when I put my kit on my car

Thats why what dave said:

is 100% correct, I went back and corrected my install after I read his write up, and my FC is very happy, I have had my kit on FI and Carb'd FC's, and now back on a FI setup , tapped into the secondary fuel rail banjo bolt

 

Isn't that they best place in the world for that fitting to go!! Almost like Mazda did that on purpose

 

Sorry, but everytime i say Nitrous backfire, people think i mean through the exhaust. I've heard several tuners call them a Hiccup......Versus a fart i guess. I wouldn't have tapped it on the throttle body. Instead on the intake elbow (just in front of the TB) To make sure that there is a good even mixture. Also i hope you pointed the fogger in the downstream direction. This stuff comes out at very high pressures. So if faced the wron way, you could have Nitrous and fuel going back through the intake, and possibly puddling. Which is a VERY bad thing. I think that a window switch (rpm based limits ) is a good thing, because it protects you from loss of traction. just an added safety. Just my opinion. I use a Haltech. So what the hell do i know.

 

Yeah its facing downstream. What does everyone else think about plumbing it further back from the TB? I have a front mount so the mentioned elbow isnt there but I could put it about 5" back if needed.

 

Question.
How much can an N/A handle in 3rd and 4th gear?

 

Easily 100 shot with a wet setup. It's all in the fuel management and tuning.

 

whats the better way to go, wet or dry? assuming im not going to run anything higher than like a 50 or 75 shot?

 

wet,just to be on the safe side

 

How big of a fuel pump do you got?
With a wet shot, if you have a properly built fuel system, 150 is easily possible. I run 200hp in stages on my ported, stock internals S5 TII.

As for WET vs. Dry: both have their advantages.
Since the fuel injectors are usually pretty taxed on a RX-7, dry usually isn't the best option without an injector upgrade.
Wet works great if you have a big enough fuel pump for it, and as long as you don't hit it before 3000 rpm (allows for nitrous backfire. you should never hit below 3000 rpm with a dry shot anyways, but a dry shot just eliminates the chance of a explosion firing back through the intake manifolds.)
Really, it depends on your goals. 50-60 hp is a great set-up for a dry system. Any more, and go wet.

Sean Cathcart

 

So I just want to confirm, it is normal for the TB and 1/2 the upper man to get totally frosted after spraying? Its not a leak? Scathcart running a 200 shot is crazy. That motor must be really well tuned! Do you retard the timing? Whats your secret?!

 

No, its not a leak. It is completely normal. The release of nitrous oxide is very, VERY cold. You should see frost on the line, the AN fitting, the fogger nozzle, the TB, and various other parts. Something would be wrong if you didn't.

My several secrets:
excessive overkill. I have an aeromotive 1200 hp pump, so I have plenty of fuel, and braided lines and a regulator from the same company, so fuel delivery is not a problem.

I use an MSD box to retard timing via retard addition for each shot IE: the unit has several stages of retard. I retard 2 degreed for the 80 shot, and 4 degrees for the 120 shot, and when the two are activated together, the total retard is the sum of the two, or 6 degrees total reatrd).

I run microswitches so it only opens at wide open throttle, and only hit above 3000 rpm. I use the two shot comaster switches to control when which mes on, usually the TB single fogger 80 shot first, followed by the 120 shot, but I have hit them together.

I have a ported motor and ported intakes. Porting allows for a little extra nitrous. Also, the second stage is direct port, so it is a little more evenly distributed into the runners.

I creep too, even with a massively ported S5 wastegate. I always let off at 10 psi.

My motor is pretty-well tuned, stock ecu, stock cleaned and balanced injectors, 7K on ported motor, perfect timing, perfect air/fuel ratios (until I get too high in the boost area....)

And my last and final secret: I've been budgeting a new motor for some time, and although I don't think I'll kill this motor, I push the engine without any hesitation.
Coming next: 2 intermediate-bearing 3 rotor.

My only suggestion to you would be: move the fogger nozzle back and hook up a WOT microswitch in series with the electrical system. Maybe add some retard, as you are getting up in the requirement area. Good luck, and keep in mind this upgrade is absolutely awesome for after a turbo upgrade. They go great together, like *****'s and vagina's.

Let me know if you sort it out, or need anything else cleared up.
Sean Cathcart

 

Sean is right on with his posts, and he backs up what I try to hit home as often as possible. NOS systems on rotaries is like FD owners modifying their cars. Alot of people don't do it right, it blows up, and it gives nitrous (or 13B-REW's) a bad wrap. (sorry FD guys ) But if you install the nitrous correctly, and tune the car correctly, and prepare your car for the nitrous, then you can run alot of it with no problems.

As far as the wet/dry arguement, most people lean towards the wet system. It is much more forgiving than a dry system. As much as our engines love fuel, why not give it what it likes?

 

Cool, thanx for the input, it is very appreciated. I have already hooked up a hobbs switch to the TB. My remaining questions are as follows

1. Should I tee fuel from the return rubber line under the brake booster?

2. How many inches behind the (gone now) secondary throttle plates should I plumb the fogger(1,2,3,4,?)?

4. With boost creeping to about 13 pounds on a stock turbo and a 50 shot(plenty of fuel) is stock timing kosher?


Thanx so much (all of you guys) for the help.

 

mine don't run hot and i have ran it around a race track and it never get up above half

 

I don't understand why he's running nos on a turbo........

Isn't there plenty of other mods to do? NOS seems like it would be better suited on an NA, as a final mod.

 

1. Definitely not. That fuel is "bled" from the fuel pressure regulator. It is under changing fuel pressure, and nitrous tuning would be impossible. Best place is after the secondary fuel rails, but before the fuel pressure regulator.

2. Doesn't really matter. 3-4" is about what I have.

3. What happened to 3?? lol

4. Stock timing should be ok.

 

NOS= lots of horsepower for very little money. Its easy to use, and only comes on when you need it.

There are plenty of other mods, but why should some mods be placed above others? For example: why spend $100 on pullies that will only decrease your charging capabilities and net (maybe) 3 hp?

NOS is also great when you go for larger turbo upgrades. The extra gases you introduce at 3000 rpm help larger turbo's to spool.

 

on my large SP Series 5 motor, i plan on running a 150 shot in 2 stage. 50 and 100. plus SAFC and a whole lot of other sh*t

Justin

 

I have a J spec, so the pulse dampner is on the end of the secondary fuel rail. So where EXACTLY should I tee for fuel?

 

I got a quick question about all this Nos talk.

How dangerous is it? If I got it professionally installed is there still a big risk? I have heard of someone here in Texas that had nos and supposedly the tank exploded from the heat here in Texas.

I am thinking of NOS as a future upgrade. But before I do that I plan on upgrading my Fuel Injectors (from 550 to 720's) and putting a Walbro Fuel pump then adding a S-AFC. This will all be in a 1990 TII

 

To you: VERY dangerous. You are stereotype of the person who would have an accident with it. Those with very limited knowledge of nitrous oxide systems are the most likely to have the most problems. Getting it professionally installed would be a good idea, but they are most likely just to install the kit, with none of the accessories necessary to make a safe kit.

Your best bet is learning as much about nitrous oxide systems as possible and installing the kit yourself. Experience is the best thing you can have when it comes to cars.

As for the tank explosion... seems a little unlikely, but possible: yes. An insulated bottle blanket will help keep the temps constant, keeping heat in when cold, and heat out when hot.
This is also when professionally-installed kits come into play. A great accessory to install is a safety pressure blow-off valve. Should the bottle get too hot from heat or leaving a bottle warmer on, mis-directet exhaust, or whatever, should the pressure exceed 1000 -or-so psi and become hazardous to the bottle capablilities, the nitrous would be released via a vent tube to outside of the car.
NOS makes this accessory, but I'm sure other nitrous companies do as well.

Really, I wouldn't reccommend nitrous to you unless you beef up your knowledge on the subject. one of the Chevy magazines out right now has a Fantastic article on nitrous oxide right now. I can't remember the name, but it's a cover story and has a cross-spray bar carb setup picture that really stands out on the cover.
Pick up the magazine.

Am I the only one who keeps tabs on all the other magazines? I like to get ideas on what the competition is running.

 

How about an exact description of the fuel line set-up, or maybe a photoshop or "paint" diagram? A little trouble trying to picture the set up.

 

The only thing i could think of is you mounted your fogger to close to the trottlebody? your going to need about 8-10 " of space between your fogger and Tb for the N20 and gas to adamize I run a line lock button also! never had a problem? i try to run my car @WOT for a few seconds after i'm off the bottle to clear all fuel form the intake!

 

Scathcart:

Thankyou so much for the info.

I am in the middle of learning more about it as we speak. I am always the type of person that will learn before I go into anything serious like this.

I am new to the whole RX7 thing actually.

The past few months I have done by myself (with help on the forum) a HKS BOV, Cone Filter install, Turbo Timer and Indiglo guages.

Yes I know that stuff is simple, but I am starting small before I get into anything like NOS or what not.

My next thing will be a Exhaust system, upgraded Fuel Pump and injectors. I am thinking of getting secondary injectors with a S-AFC. Anyway I will want to finish all of this before I even decide to do NOS on my own.

You got to crawl before you can walk

 

I wont know what the fuel parts "inline order" is till I pull the upper manifold tomarow. I do know that the pulse dampner sits just below the lift hoof unnder the upper manifold, at the end of the secondary fuel rail, and the FR is in the location the pD would be on a american rex.