I know the bare bones of how NOS works, but I'd like to see a more detailed info set, like the different types of installations, pros/cons of each, etc. I would love to see any other mods needed to make the system work (hopefully with some numbers), like "you have to raise your thermostat temp setting 5 degrees for every 10 HP of boost you want" (obviously made that up, but that's the hardcore stuff I'm begging for).

Any links, mag articles, etc.? I don't mind reading articles that tout one particular brand, AS LONG AS there is info that pertains to NOS apps in general (i.e., I don't want an article that only states "OUR brand beats the competition by 10%, liter per liter").

Many thanks!

 

Here are some brands. If you are going with a small shot (up to 50hp) usually no other mods are needed.

http://www.venom-performance.com
http://www.nitrousexpress.com
http://www.zex.com
http://www.nosnitrous.com

 

A few comments from my experience (btw, I will use NOS as an abbreviation for nitrous, even though it's really a brand name for one manufacturer):

First things first, nitrous oxide is an oxidant. It doesn't burn on its own and it doesn't make any power on its own. But, when combined with fuel and heat (such that the oxygen is liberated from the nitrogen), there is lots of power to be made since nitrous oxide contains much more oxygen by percentage than our everyday breathable air. The nitrogen also acts as a combustion buffer and because the substance is used as a highly compressed gas, there is a cooling effect when it is discharged into the intake tract, which adds additional power.

1. Stay away from dry systems if you don't have an appropriate engine control system (and Honda's don't). Dry systems add nos only through the nozzle and then count on the fuel injectors to add extra fuel, usually by boosting fuel pressure when the NOS is injected. Just too risky with too much margin for error and if you play it safe with an extra rich fuel setting, you don't gain max power.

2. Single fogger wet systems, which have a single nozzle each for NOS and fuel, are better in that they ensure an appropriate amount of extra fuel is being injected. However, the problem with them is that most intake manifold (including the one on your S2K) are designed to flow "dry", meaning they aren't good at distributing liquids in equal amounts to each cylinder. Thus that carefully metered mixture may end up getting split differently between different cylinders when you inject it before the throttle body. For small amounts of power (say under 50) you can get away with it.

3. Direct port systems are preferable to all IMO. They place an individual fuel and NOS nozzle in each intake runner, usually just behind the fuel injector. Thus, each cylinder gets an appropriately metered amount of fuel and NOS. The drawback to such a system is expense, and because the nozzles tend to have a minimum flow rate, it's tough to use such a system if you want to produce less than 70-80 hp of added power.

4. Fuel supply is the most critical thing with NOS. If you run lean, you will burn pistons and valves. The S2K's forged pistons are stronger than most factory pistons, but they'll still get eaten. Thus, a system which has a nitrous shut off tied to a fuel pressure sensor is very helpful. That way if you lose fuel for any reason, the nitrous stops flowing.

5. When tuning, always start "rich and retarded" (kinda like George W. eh? Just kidding). I didn't coin that phrase, but it works. A rich mixture and retarded timing will avoid problems. I've seen lots of recommendations on how retarded, but most seem to say 1-2 degrees for every 50 hp. It will depend on the application, so listen to the manufacturer and go even more retarded to start with. Oh, and learn to read sparkplugs if you want to run the stuff. They're the windows to the engine's health.

UL

 

turbo,

I've come across all four of those systems before in mags. I hate to admit advertising is really doing it's job here, but the Venom system seems to be the most "together", allowing me to use the gas a bit at a time, instead of always on or on only at WOT. I also like the tips provided, such as starting off at 5% NOS and working up from there, generally staying below 50% of standard engine HP as an increase, etc.

I'm looking for something in the area of a 50-70 shot in the lower RPM range...just enough to smooth out the powerband a bit, maybe give me a bit more boost on the high end.




ultimate,

Now THAT is some good info...exactly the type I'm looking for. I wish I could have your NOS knowledge in a little database that I could look up when I suddenly had a question.

From my understanding, the Venom system is a dry type (uses the stock nozzle for both NOS and fuel delivery to each piston), so should I stay far away from this system, even if it seems to have some really decent tuning features?

I spent some time on the Holley site for their NOS systems, and it looked as if they offered both fogger and direct port systems. If direct port is the only way to go with our babies, and the price is too high ($500-$600 was about right for me for the Venom system), I'll just have to scrap the idea for now. Wat would a direct port require, new heads that allow for two nozzles on each piston, etc.?

What other options would be very useful, yet still relatively inexpensive, for this type of system...fuel pressure regulator, fuel rail, etc.?

 

If the Venom is a dry system (and I don't know that it is), then yes, I wouldn't want it. A dry system will not come with any fuel nozzles or fuel lines. Just a different fuel pressure regulator and the NOS lines.

A "Fogger" is historically just a type of nozzle. Some carb systems will use a spray bar just below the carb and above the intake manifold (acts kind of like a carb spacer if you know what that is). These spray bars (usually one for fuel and one for nitrous) have little holes drilled in them to mist the nitrous and fuel into the intake tract. The actual amount is controlled by a specific "jet" leading into each bar.

A typical direct port system for Hondas will cost around $500, but that just includes 4 fuel/nitrous combined nozzles, all the nitrous and fuel line you'll need, distribution blocks, hard lines (which need to be bent to fit, not always a good thing for a beginner), often times a fuel pressure regulator, nitrous tank and maybe an underhood fuel pump. What you don't get is any kind of nitrous control system. Both NOS and Jacob's Electronics offer some nice pieces that will give you progressive onset of the nitrous by pulsing the solenoids, have rev limit and fuel pressure protection and some other things. These run another $300-$500, but they're very useful.

Oh, and on the direct port you have to tap the intake manifold in each runner for a nozzle. That means taking the manifold off. You won't need a new one though.

If you really want to do a system properly (i.e., direct port, controller, pro install) you should expect to drop at least $1000 and as much as $1500 depending upon options. It's still the cheapest way to add up to 100 hp or more to any car (save some factory turbo cars). I don't recommend skimping on these things either, because if you screw up with nitrous you lose engines (notice, I said _if_ you screw up, it doesn't have to happen). Not like an exhaust or intake where you lose a little power and a little money. And factory techs can usually tell a nitrous induced failure when they open up an engine if they've got half a brain in their heads.

Also, it's very important that you don't do a big shot of NOS at low rpm. This is because when a nitrous system is set up for, say, 100 hp it's spraying enough fuel and NOS into each cylinder for an additional 25 hp. But it doesn't pulse the spray for each cylinder event, it just keeps spraying as long as you're hitting the button. Now, if you spray at 4000 rpm, you're adding a fixed amount of NOS/fuel mixture for each firing event. If you're still spraying at 8000 rpm, you're getting half that amount per firing event. At 4000 rpm you may be adding 30 lbs-ft of torque per cylinder, so at 8000 rpm you'll be adding only 15 lbs-ft per cylinder. Because of hp's relationship to torque and rpm (in english units, hp = torque x rpm/5252) you'll be adding 25 hp per cylinder the whole time, but the average cylinder pressure increase will be lower at high rpms. That's why people tell you not to hit NOS at too low an rpm because cylinder pressures get higher and higher the lower you go. A 100 hp boost at 2500 rpm will be adding 200 lbs-ft of torque to your engine (more than it originally made!) and may cause some harm, either short term or long term. That's why progressive controllers that add more nitrous as rpms come up are preferable.

UL

 

ultimate,

Again, good stuff to know. So, I suppose $1000 is not too far out of reach for the performance gain. Which system(s) would you suggest I look into more heavily, then? Should I consider adding more than a 50 shot (say, closer to 100?) if I'm going to put that much money into it, or would I be pushing the stock engine too far?

I liked the Venom system because you could modify multiple items, such as how the boost ramps up, min/max RPM ranges, etc. AND do it graphically instead of adjusting-measure-adjusting-measure.

I've never done anything major to an engine such as taking the heads off, but I think I'm intelligent enough to follow directions and ask the right questions (I hope!). I've done simple stuff, like swapping out intakes (TB next?), so this upgrade is the next logical step (SC is too much work for the moment).

 

I took a look at the Venom system and, frankly, if I were going to do a dry system, that would be the one. Otherwise, I'd look at the NOS systems from Holley, and you might also talk to Nitrous Express. However, both of their websites are lacking info compared to Venom's. I have to admit, I'm impressed by what Venom offers so far.

Keep investigating.

UL

 

Zex also makes good kits, but some people are too embarassed to have a purple bottle (I have a friend like this). NOS (the company) kits are kinda toy-like.

But really, I'd say anything more than a 50 shot will just be pushing the motor too far. Even a 50 shot I would run on 104 race gas, just to make sure to keep detonation to a minimum. Keep in mind you're running very high compression to begin with. But that's just my take on things... I tend to think better safe than sorry.

my .02

 

I have a great deal of experience with NOS kits on imports, both dry and otherwise. I would stay away from the Venom kit and the ZEX kit. Neither are direct port and neither produce the dyno numbers that the NOS (namebrand) kit do. I would definitely go direct port (which I'm in the process of doing now). I'm starting out with a 60 shot and am using the NOS kit because it was cheaper than the Nitrous Express kit. Both kits are of comparable quality but I like the stainless steel lines that the NX kit comes with a little better. Also, the guys at NX are very helpful. If you're going with 80-100 shot I would go with the NOS digital progressive controller. My stock 93 Prelude Si w/ 100 shot and the progressive controller dropped from low 16's in the quarter to low 13's and it had a completely stock automatic tranny. Just FYI, I am expecting a 60 shot to drop the quarter mile time to mid to upper 12's from the current mid to upper 13's.