Turbo Spooling Nitrous Oxide System Basics

[Alky V6]

I've been getting some inquiries about what nitrous system to use with the Turbo Buicks to help with spooling problems. I think it's time to start a thread to discuss this. I'd like to simply go over the basics of a simple 50-100 shot, single fogger nozzle setup, and add in some simple system control information. Let's make this the thread people can go to when they're interested in putting together their own system or give them enough basic nitrous system information that can arm a person that is looking into purchasing a ready made nitrous system package.

If people have used certain nitrous kits with good results, feel free to plug in your preference and maybe list the features that make it a good choice.

I would prefer to keep the control systems simple, but if anyone wants to put in a plug for more complicated systems, that's perfectly fine. The more knowledge people are armed with, the easier it will be for them to look at different systems or components and figure out what is useful for their situation, or what is not.

I'll start out with a 10 lb. nitrous bottle with a valve that will support the amount of nitrous flow that your hp shot level demands. I can't imagine a valve that wouldn't support a 100 shot, so shopping for a bottle and valve that will work shouldn't be a problem. If the plan is to go to larger, crazier shot sizes, just make sure the valve size will support it.

Next important basic component. The injection nozzle(s).

 

[Alky V6]

Injection Nozzles

To keep things as simple as possible and to get the best results, I prefer a single fogger type nozzle. I'm not going to recommend a make of nozzle. That will be up to you gentlemen to explore.
I would look for one that is going to provide the best mixing and atomization of the nitrous and fuel as/after it exits the nozzle.
With the basic intake manifold design that we're stuck with, the nitrous/fuel (n/f) will need to make a sharp turn to make it to the front cylinders with as little fuel fall out as possible. Too much fuel fall out could cause a lean burn condition and could setup a lean intake manifold backfire that could possibly damage the intake manifold if there isn't some type of blowoff device to save the intake manifold. Make sure the ignition system and spark plugs (fresh set, smaller gaps) are up to par. No ignition missing allowed when the nitrous system activates. Deal?
The position of the nozzle is important. The nozzle should be placed far enough forward of the throttle body so that the n/f mix has time to vaporize a good amount before it has to make the turns after the throttle body. The position that is commonly used with alky injection systems should do fine for wet nitrous systems also.
The better atomized and vaporized the n/f mix is, the better chance it has of making any turns in the intake manifold.

Which direction to inject the n/f mix? Downstream or upstream. Personally, I think you would get a better mix with the incoming air if the n/f was injected into the oncoming air flow from the intercooler.

Some may feel injecting the nitrous before the intercooler would be a better idea. I don't like the idea of having so much n/f mixture volume going on before the intake valve. If an intake backfire did happen to occur, all that volume could be ignited, including in your intercooler. Not too sure the intercooler would survive that.

If you haven't picked it up yet, I prefer a wet system over a dry system. I feel a person has better control of the n/f ratio throughout the duration of the hit with a wet system, over waiting for the O2 to sense a lean signal and then start correcting that with more electronic injector pulse width.

Next. Mounting of the nitrous bottle.

 

[titan1]

subscribed

 

[mr go fast]

subscribed

yep:biggrin:

 

[Alky V6]

Bottle Mounting

I'll cover the typical mounting style and location for nitrous bottles in a stree/strip car.
The bottle valve on a nitrous bottle has a siphon tube attached to it that runs to the bottom edge of the bottle. The side of the bottle that the pickup end of the siphon tube rests at is the same side of the bottle that the valve hose connection is at, just at the other end of the bottle. The valve handle would be on the other side of the bottle. That is why you always see nitrous bottles mounted with the valve handle facing upwards.
The bottle is mounted in the trunk in a manner such that the bottom of the bottle is towards the rear of the car and at a lower position than the top or valve end of the bottle. This is so that car acceleration always keeps the liquid nitrous content in the bottle at the pickup point of the siphon tube. Again, the bottle is mounted so that the valve handle is facing upwards for easy access, and to keep the pickup end of the valve siphon tube at the lowest possible position. We want to always pickup liquid nitrous from the bottle, not gaseous nitrous.

The nitrous content inside the bottle is a mix of liquid nitrous at the lower part of the bottle with gaseous nitrous above the liquid nitrous. The chemical properties of nitrous oxide allow the bottle to self pressurize and maintain a certain equilibrium of liquid nitrous and gaseous nitrous. Temperature of the bottle plays a very important part in this equilibrium and the amount of pressure that the nitrous oxide maintains in the bottle. We'll go over that later. The only thing I'll say about that right now is, DO NOT mount the bottle in a place where direct sunlight will constantly be shining on the bottle(s). That will make temperature control, and thus pressure control of the bottle very, very difficult.

 

[cruzn57]

do not let sun light contact the bottle?

How would you know that? LOL :biggrin:

here is a simple setup I'm using, haven't tried it out yet, but VERY SOON.
wet, but w/ fast to correct a/f ratio.

 

[Alky V6]

LOL Yes. Racing on a 101F day where the bottle intermittently gets some sunlight on it can make pressure control of the bottle interesting. Lee was there with me when I learned that one. I'll share that experience, and how we remedied the situation later.

Personally, I would have mounted the injection nozzle further forward, nearer the bend of the uppipe to give the mixture more time to vaporize before it had to make the turn after the throttle body. Or,... if the nozzle is spraying into the oncoming airflow? Let us know how it turns out.

Lee, what shot size are you starting out with?

Next we'll cover the solenoids, and initial activation and deactivation flow tuning considerations that are tied to the mounting locations of the solenoids.

 

[cruzn57]

I dunno.

probably 75 shot to start,
my ace tuner doesn't think we will need any assist,
gonna use the new Bailey 2 step with ign retard to control launch rpm,
and ams 500 for boost control.
nozzle sprays into throttle body.

 

[HighPSI]

I have never had to use anything more than a 50 shot. I prefer to use a dry shot and tune the fuel with the computer. It makes the install even simpler and I find it easier to get the correct A/F throughout the rpm band.

 

[Alky V6]

I have never had to use anything more than a 50 shot. I prefer to use a dry shot and tune the fuel with the computer. It makes the install even simpler and I find it easier to get the correct A/F throughout the rpm band.

I wanted to start out with outlining as simple a system as possible without having to upgrade the ECM. We could move into more complicated setups after we outline the simplest and cheapest setups. I'm worried about the amount of delay time with the O2 sensor reading and the stock ECM.
I agree with the shot size. Most should find that a 50 shot will be enough. Whether more than a 50 shot is needed or not would depend on how matched the turbo is with the nitrous system. If a person is looking for better breathing on the top end, he could go larger on the turbine side, and compressor side for that matter, and use the nitrous shot size to compensate for the additional lag that would result.

So, can a dry system be made to work with a stock ECM?

 

[Alky V6]

This is what I worry about with a dry system. When the nitrous hits, and with a dry system hopefully it is a small shot size, the cylinders will be firing a certain number of times before the lean exhaust reaches the O2 sensor, the O2 sensor reacts, and the ECM corrects with enough authority to get the charge ratio where it needs to be.
If you're using a wideband, the sensor is even further downstream making that time a little longer.
Typically, it will take 0.20 of a second or longer before the lean exhaust is detected by the ECM. Then the correct amount of adjustment to the injector pulse width still needs to take place.

How many times has the cylinder fired with a lean mixture during 1/2 second. Let's use 2400 rpm. That calculates out to 10 ignition cycles per 1/2 second. The cylinder will have fired with a dangerously lean mixture for 10 ignition cycles. Five times for 1/4 of a second.
With a properly setup wet system, you could have the cylinders firing with an overly rich mixture for a short period of time rather than firing lean for a short period of time. Richer is much safer.

Nitrous users know that firing a lean mixture is asking for a lean intake backfire if luck doesn't go your way.

I'm not saying that a small dry system should be avoided at all costs, obviously it works fine for some, and hopefully more people that have experience with dry systems with the stock ECM might chime in with their experiences. I can only relate to my experiences, and my experience with much larger shot sizes, I can tell you that I do everything in my power to avoid any lean firing when on the nitrous.

 

[TurboBob]

So, can a dry system be made to work with a stock ECM?

yes

 

[TurboBob]

This is what I worry about with a dry system. When the nitrous hits, and with a dry system hopefully it is a small shot size, the cylinders will be firing a certain number of times before the lean exhaust reaches the O2 sensor, the O2 sensor reacts, and the ECM corrects with enough authority to get the charge ratio where it needs to be.
If you're using a wideband, the sensor is even further downstream making that time a little longer.
Typically, it will take 0.20 of a second or longer before the lean exhaust is detected by the ECM. Then the correct amount of adjustment to the injector pulse width still needs to take place.

How many times has the cylinder fired with a lean mixture during 1/2 second. Let's use 2400 rpm. That calculates out to 10 ignition cycles per 1/2 second. The cylinder will have fired with a dangerously lean mixture for 10 ignition cycles. Five times for 1/4 of a second.
With a properly setup wet system, you could have the cylinders firing with an overly rich mixture for a short period of time rather than firing lean for a short period of time. Richer is much safer.

Nitrous users know that firing a lean mixture is asking for a lean intake backfire if luck doesn't go your way.

You just don't rely on the O2 correction to handle it, but let the ECM know when you are spraying so extra fuel can be added. Lots of ways to do this.

Bob

 

[Alky V6]

You just don't rely on the O2 correction to handle it, but let the ECM know when you are spraying so extra fuel can be added. Lots of ways to do this.

Bob

Please elaborate for everyone Bob. If that could be done with the proper amount of correction, then that would be the ticket for sure. People obviously would be very interesting in finding a source for such a system. I'm assuming a reprogrammed OEM controller. Please include that information.

 

[Otto J]

This is what I worry about with a dry system. When the nitrous hits, and with a dry system hopefully it is a small shot size, the cylinders will be firing a certain number of times before the lean exhaust reaches the O2 sensor, the O2 sensor reacts, and the ECM corrects with enough authority to get the charge ratio where it needs to be.
If you're using a wideband, the sensor is even further downstream making that time a little longer.
Typically, it will take 0.20 of a second or longer before the lean exhaust is detected by the ECM. Then the correct amount of adjustment to the injector pulse width still needs to take place.

How many times has the cylinder fired with a lean mixture during 1/2 second. Let's use 2400 rpm. That calculates out to 10 ignition cycles per 1/2 second. The cylinder will have fired with a dangerously lean mixture for 10 ignition cycles. Five times for 1/4 of a second.
With a properly setup wet system, you could have the cylinders firing with an overly rich mixture for a short period of time rather than firing lean for a short period of time. Richer is much safer.

Nitrous users know that firing a lean mixture is asking for a lean intake backfire if luck doesn't go your way.

I'm not saying that a small dry system should be avoided at all costs, obviously it works fine for some, and hopefully more people that have experience with dry systems with the stock ECM might chime in with their experiences. I can only relate to my experiences, and my experience with much larger shot sizes, I can tell you that I do everything in my power to avoid any lean firing when on the nitrous.

I built a camaro with 2 stages of nitrous run DRY with an XFI amounting to over 500 hp to the tires and it never skips a beat.
start fat and tune lean. You would be amazed how lean a nitrous motor runs compared to a turbo motor for best/safe HP.
You might not even spool your car as lean as it runs

 

[Alky V6]

I built a camaro with 2 stages of nitrous run DRY with an XFI amounting to over 500 hp to the tires and it never skips a beat.
start fat and tune lean. You would be amazed how lean a nitrous motor runs compared to a turbo motor for best/safe HP.
You might not even spool your car as lean as it runs

If I'm not mistaken, the XFI has an alternative fuel table that it switches to when it sees nitrous activation? Is that right? That would certainly avoid any lean firing while waiting on the O2 sensor(s).

 

[TurboBob]

If I'm not mistaken, the XFI has an alternative fuel table that it switches to when it sees nitrous activation? Is that right? That would certainly avoid any lean firing while waiting on the O2 sensor(s).

this is how you would do it with an XFI/DFI/BS3/TEC........

There are several ways to duplicate this with the stock ECM.

one is to rely on the richness caused by intercooler filling when spooling. just shut the N2O off before you reach target boost.

Or, with a small shot, tune a little rich and let the N2O lean it back to where it spools the best.

Or you can use the aux trigger input on a MAFt Gen-2 or MAFt Pro to activate the aux fuel compensation settings contained within.

Or an adjustable parameter could be activated in a patched stock style chip. (I have stuff that works like this, but not this exactly)

Lots of ways to skin this cat.

Bob

 

[Chevota]

50 shot, dry, 8-12in pre-compressor FTW.

 

[Alky V6]

50 shot, dry, 8-12in pre-compressor FTW.

This method would hit much softer than a system where a nozzle would be placed at the throttle body. I could see where the O2 alone could compensate well enough where the nitrous injection is taking place so far from the intake manifold. Nice.

 

[818GN]

Subscribed as well.