xproductionz

iTrader: (14)

Here i have a bunch of definitions and termonology and other stuff explained all in one place. Each one is broken down into each of there own section.

I also have these and more up on my site at xproductionz.com as a sticky in case you need another source to find these in.

Well here i go

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Compressors and Turbines Terminology


Compressor- Essentially a fan that spins and compresses air within an enclosed area (compressor housing). In order to allow the air to compress and build pressure within the housing, the fan must be spun at certain rpm levels.


Compressor Housing- Housing that encloses the compressor.


Compressor Map- A map that allows the ability to plot compressor pressure ratio vs. engine airflow. An “island” shape is created on the plot showing where the compressor is efficient.


Compressor efficiency- Compressors efficiency is the ability to produce lowest possible temperature from the compressor air. When air is compressed heat is generated, at certain range of speeds of the compressor rotation the heat can be keep to a minimum. This is what is known as “being in the efficiency range of a compressor” Higher efficiency, lower outlet temperatures. Highest possible efficiency of compressors are 78~82%. Lower outlet temperature=lower intake air temperature. Lower intake air temperature=more dense mixture of air=more oxygen available in the combustion to burn. The greater amount of oxygen present with fuel provides more energy. More energy=more heat=more torque=more power.


Compressor Trim- The trim of the compressor refers to the squared ratio of the smaller diameter divided by the larger diameter multiplied by 100 of the compressor wheel. The smaller diameter of the wheel is known as the inducer, and the larger diameter of the wheel is known as the exducer.


Compressor Families- Beyond compressor trim levels there is compressor family of wheels. In the Garret turbo line of older technology compressors there is T22, T25, T3, T350, T04b, T04e, T04s and T04r families. In each family there is trim levels to the family. Although there is a 60 trim in both the t3 and to4e family wheels, the main difference is the inducer diameter of the wheels. The trim is only a ratio of the exducer/inducer, so while the inducer size of the compressor wheels are vastly different, the ratio between the exducer/inducer remains constant since it’s the comparison between the exducer to inducer size.


Turbine- A fan that uses exhaust energy to rotate. The rotation of the turbine is transmitted through a shaft that is connected to the compressor. Faster the turbine spins, faster the compressor spins. Compressor uses the rpm translation through the turbine/compressor-connecting shaft to compress air at the rpm level that dictates compressor flow.


Turbine Housing- Housing that encloses the turbine wheel. Turbine housing size affects the ability of the turbine to transmit rpm to the compressor wheel. Smaller turbine housing, quicker spool up due to quicker translation of rpm’s to compressor. Trade-off is increased low-end response for less high-end response from turbocharger. Picture below is a turbine housing.



Turbine Trim- The trim of the turbine refers to the squared ratio of the smaller diameter divided by the larger diameter multiplied by 100 of the compressor wheel. The smaller diameter of the wheel is known as the inducer, and the larger diameter of the wheel is known as the exducer.


Turbine Families- As with compressor families, there is turbine families. The most common evidence of the turbine families is the t31, t350 and t04 wheel used in the t3, t3/t4 turbos sold on the market. Precision offers the t31, aka stage 3 blade in their smaller line of sport compact series turbochargers. The t31 comes in two different trim levels the 69 and 76 trim. The t350, aka stage 5 blade comes in two different trim levels as well, 69 and 76 trim. The t31 will spool faster than the t350 due to the physical size differences (t31 being smaller). The smaller the trim level the quicker spool, but less top end. Essentially you are changing the turbine pressure ratio when you are selecting the family and trim level of the turbine wheel you are using. The larger family and trim level you choose the more power the turbocharger will produce at the expense of lag. As with the compressor trim levels both the t31 and t350 have the 69 and 76 trim levels, which are not the same. The turbine trim is the ratio of the exducer compared to the inducer size of the turbine wheel, since its only a ratio the size of the inducer/exducers are completely different.


Turbine Map- A map that allows the ability to plot turbine expansion ratio vs. engine airflow. An “island” shape is created on the plot showing where the turbine is efficient.


A/R- Ratio of the area of the compressor/turbine housing to the radius of the compressor/turbine wheel. In order to find out the A/R of the compressor or turbine housing select a point where the compressor/turbine housing begins and measure the cross-sectional area at that point. Cross sectional area is A=P*(Radius)2. Next step is to measure the distance between the center of the area and the center of the compressor/turbine wheel, this is the radius measurement. If you choose a different point on the compressor/turbine housing and remeasure the area and radius, you’ll find that it stays constant. This is due to the housing getting constantly smaller in diameter as it gets closer and closer to the compressor/turbine wheel.


When you upgrade from a .48 to a .63, or .63 to a .82 A/R you are essentially increasing the area of the housing. Increasing the area increases the amount airflow to the turbine wheel. The smaller area of the smaller turbine housing builds pressure quickly and transmits this pressure to the turbine. The pressure gives the turbine enough rpm’s to allow the compressor to compress air at lower engine speeds (less engine speed, less airflow from engine). The trade off is that pressure builds up quickly in the housing to obtain quick spool up, but the pressure quickly becomes to great and backpressure builds up. The backpressure is the restriction that limits shaft speed of the compressor, and as the rpm increase (engine airflow increases) the torque curve begins to drop off due to the volumetric efficiency of the engine decreasing. Think of the turbine housing sizing as increasing/decreasing inlet pressure to the housing in order to gain low end, midrange or top-end response from the turbocharger. The smaller turbine housing wont carry the torque curve to a high rpm, limiting the amount of peak whp. Excellent low-end and midrange gains are felt through smaller housings.


Compressor/Turbine mismatch- When “matching” a compressor and a turbine you are seeking to balance the turbine characteristics to the compressor characteristics. When you increase the size of the turbine wheel you are decreasing the pressure ratio of the turbine, essentially decreasing the shaft speed connecting the compressor/turbine. When pairing a larger turbine wheel to a small compressor wheel, the smaller the compressor wheel the higher the rpm the wheel has to be spun at to compress the air. This becomes a problem in that the smaller compressor cannot generate adequate shaft speed to compress air. The same can hold true when pairing a huge compressor to a small turbine wheel. The larger compressor needs less shaft speed to compressor airflow, but the smaller turbine wheel will spin at a much higher rpm level that is what is necessary. The result is crossing over the choke or surge line on the compressor map. Note the two different compressor maps, one of a 60 trim t3 compressor wheel, the other a t64 compressor wheel.

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Why Horsepower deosnt matter!!

For the last century, horsepower has been used to describe the power output of the internal combustion engine. The horsepower unit was created by James Watt in the 18th century. Its origin is based from how much power a horse could lift in foot pounds, 33,000 ft-lbs to be exact in one minute. The unit is derived from torque, which is the true measurement of the engine physical power production.

What is strange about the units of horsepower is that it has no physical meaning. Its an arbitrary unit that has no real signficance in describing the characterisitc of the engine. For those that are curious to calculate horsepower:

Horsepower=(rpm/5252)*torque

From this equation you can see that horsepower is nothing more than a contrived unit that is based purely from torque and rpm. You'll notice the number 5252 in the equation, this represents the point at which every dyno graph must intersect horsepower and torque. Its a mathematical relationship, both strange and interesting since horsepower is a function of torque and rpm.

There has been much confusion and rumors across the internet about gaining more horsepower. In essence, gaining more horsepower is gaining torque. If you are after "peak" horsepower, you are interesting in carrying the torque curve as high in the rpm range without falling as possible. You can see from the equation that as the rpm's increase, and the torque remains the same you get a higher horsepower number.

What phsycially is happening is that the engine is able to produce enough torque to overcome frictional forces through the air, tires, etc. As you are able to keep the torque from falling off on the top end, you are able to maintain a steady torque curve that will "pull" the car through the mph you are trying to reach. So people who are after "peak" horsepower really want to extend their torque curves as far towards redline as possible, without letting the torque fall off. Check out some dyno graphs and see what I mean. Horsepower doesnt describe the true nature of how the engine performs, its the torque curve.

From a tuners perspective, you dont tune off of the horsepower curves. The physical relevance towards the engine performance is arbitrary, since the torque is truely what is effected by the fuel, timing, breathing, etc of the engine. The horsepwer is merely a concocted unit of measure, showing no true characteristics of the engine power output. A good tuner will only make changes from the torque curves, see what increase/decrease the curves show from the changes. So next time you are thinking horsepower, think "what would I want my torque curve to be"?

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VTEC Explained

VTEC for all SOHC cars explained. Before you even read this I want you all to know that all figures are from both 1996-2000 Honda tech book and 2001-2003 Honda Tech book.

To start there are three kinds of SOHC VTEC that Honda has ever produced. First there is standard SOHC VTEC this was found on the 1996-2000 civic EX (D16Y8), and the 1992-1995 EX and SI (D16Z6). This works the same as DOHC VTEC (only on the intake side no SOHC motor has VTEC on the exhaust side). By using three cam profiles and three rocker arms per cylinder, View diagrams. The second kind of SOHC VTEC is called three stage VTEC It is only found in the UK or Japan on a D15B. This kind isn’t really important to the USDM market, but if you want to read more on it follow this link.

Lee's Biases - Honda - VTEC - 3-Stage VTEC

The third and final kind of SOHC VTEC is VTEC-E This is found on the 1996-2000 civic HX and the 2001-2003 HX and (sorry to say its on the EX, yes that’s right the EX is a VTEC-E) VTEC-E is different because it only has two rocker arms and two lobes on the intake side (not Three) The way it works is from 0-4500 rpm one valve opens all the way while the other one opens less then when VTEC hits a Timing piston, spring and a Synchronizing piston all slide over locking the two together making the both open and close on the hotter cam profile. Here are the Cam specs for the D17A2

D17A2 (EX)
Intake Exhaust (Remember the bigger the number the more it opens)
PRI 38.604 mm 38.784 mm
SEC 32.848 mm

So from 0-4500 rpm it is like having the equivalent of two valves opening at 35.726 (because one Is opening all the way at 38.604mm and the other not as much at 32.848mm) (this is still hotter then a lx with a 35.299 mm (Intake) and a 37.281mm (exhaust) after VTEC hits both rocker arms ride the 38.604mm profile that much better then the LX. This is the exact same way the HX works only the HX has slightly different cam specs.

D17A6 (HX)
Intake Exhaust
PRI 38.427 mm 38.784 mm
SEC 32.197 mm

D17A1 (DX/LX)
Intake Exhaust
PRI 35.299 mm 37.281 mm

They both have VTEC-E; the VTEC-E is for economy.



Now on to older SOHC VTEC. Standard SOHC VTEC is the same type you will find in a DOHC car (only without the exhaust side) how it works is there are three cam lobes and three rocker arms on the intake side. First from 0-4800 the outside rocker arms open and close by the outside lobes. Then when VTEC hits two Synchronizing pins slide over and lock onto the Mid Rocker. The Mid rocker follows the VTEC cam lobe.

Here are the specs for the D16Y8 cam
D16Y8
Intake Exhaust
PRI 36.778 38.008
MID 38.274
SEC 37.065

So the Y8 head is better until VTEC hits on are cars then the d17a2 heads have a slight advantage.

Also another side note VTEC-E dose not use lost motion assemblies like every other kind of VTEC ever.

Here are the specs on what it takes to activate VTEC

1 Your MAP (Manifold Absolute Pressure) sensor must read 0hg (aka 0 inches of vacuum). When it reads this it will send a 3volt signal to the ECU.

2. Your throttle has to be open 100% because your TPS sensor has to send a 4.5-volt signal to the ECU.

3. Your coolant temp has to be at running temp.

4. Vehicle speed has to be above 20mph.

5. You have to have 65-80 oil psi.

6. The engine must be running at a minimum of 4500 RPM

When all of this happens your ECU sends a 12-volt signal to your VTEC solenoid.

Also a common misbelieve is that the louder you VTEC is the better. Absolutely not!

So this is it everything on SOHC VTEC. I did a lot of research (reading tech books) and a lot of talking to a lot of people. I know all the Specs here are absolutely correct because they all came from Honda Tech books.


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Cluthes and Flywheels Explained

What is some good background clutch information?

The first impulse when clutch shopping is to get "too much" clutch. This is often a very big mistake, as there will be compromises in the different types and compositions of clutches.

Clutches hold Torque, not horsepower
Most performance enthusiasts relate more to horsepower numbers rather than torque, but clutch capacity is measured in terms of torque. Think in terms of a high rpm 250 HP Honda civic versus a 250 HP Ford Powerstroke turbo diesel. The truck will need about three times the clutch capacity because the engine produces about three times the torque.

Choosing what’s best for you:
It may be difficult to know what clutch is right for a particular application since there are so many different levels of personal tolerance and many variations in design. Some people can tolerate clutch chatter, or noise, or heavy pedal effort, or shorter clutch life, higher cost, or other trade-offs. But why tolerate unnecessary issues if you don’t have to? Get the clutch that suits your needs.

What are the various clutch materials? Other than unique or specialized compositions, clutches are generally comprised of:
1. Organic
2. Kevlar
3. Ceramic
4. Feramic
5. Carbon (initially invented in 1998 by Alcon Components for the Subaru World Rally team )
6. Sintered Iron

Depending on manufacturer specifications, this list also shows the general order of the amount of force the clutch materials can hold.

Organic: Metal-fiber woven into "organic" (actually CF aramid with other materials), original-equipment style. Known for smooth engagement, long life, broad operating temperature, minimal-to-no break in period. Will take hard use, somewhat intolerant of repeated abuse (will overheat). Will return to almost full operational condition if overheated. Material is dark brown or black with visible metal fibers.

Kevlar: High-durability material more resistant to hard use. Engagement is similar to organic, but may glaze slightly in stop and go traffic, resulting in slippage until worn clean when used hard again. Higher temp range in general, but can be ruined from overheating; will not return to original characteristics if "cooked". Material is uniform yellow/green and may look slightly fuzzy when new.

Ceramic: Very high temperature material. Engagement is more abrupt. Will wear flywheel surface faster, especially in traffic situations. Due to it’s intrinsic properties, ceramic has a very high temperature range. Material is any of several light hues - gray, pink, brown.

Feramic: This unique clutch material is one that incorporates graphite and cindered iron. The result is a friction material that offers good friction coefficient, torque capacity, and smoothness of engagement.

Carbon: Very high temperature material. Engagement is more abrupt. Will wear flywheel surface faster, especially in traffic situations. Slightly more durable and flywheel-friendly compared to other aggressive clutch materials. Material is black.

Sintered Iron: Extremely high temperature material. Engagement is extremely harsh and is generally considered an “on/off switch” both due to it’s characteristics and the clutch types this material is generally associated with. It requires a special flywheel surface. Material is metallic gray in color.


What is a dual friction clutch?
A dual friction clutch is when two different friction material facings are applied to each side of the clutch disk. For added performance and service life, Kevlar is added to the pressure plate side of the clutch disk and the other side remains organic. For street and strip, a dual friction disk is often a combo of Kevlar and metal. The one flaw in this logic is that your overall holding power is then limited to the weakest holding material.


Which clutch material is right for my car?
This depends on your configuration and the manufacturer's specifications. Each manufacturer has their own "recipe" for each clutch material type so that Manufacturer A's organic clutch material (for example) can be quite different from Manufacturer B's organic clutch material. Many clutch materials can be doped with other materials to provide different characteristics than would be expected of that particular type of clutch material. Changing to a more aggressive clutch material can gain increases of 10% to as high as 60% in the amount of torque they can hold.

As to the rating of clutches, most manufacturers rate their clutches to the point of slip, instead of being able to sustain long term use at specified ratings. Torque ratings are based off of the average torque per crank rotation, if you buy a clutch which is border line with the amount of torque you put out, chances are its going to start slipping sooner than later.


Do I need a sprung or unsprung clutch?
Many do not consider this an important issue. A sprung clutch allows it to act similarly to springs on a car. In this fashion, the clutch is “engaged”, slack is taken out of the springs, and then the clutch is fully engaged. The actual amount of travel of these springs in only a few millimeters. The theory is that the springs will dampen the engagement slightly and to soften driveline shock and reduce associated clutch engagement noise. To generalize, sprung clutches are preferred for street use and unsprung clutches are preferred for racing applications.


What causes increased clutch pedal pressure?
Pressure plate clamp force. Just because you buy an aftermarket clutch does not mean you have to have a heavy clutch pedal. The amount of increase over the OEM clutch pedal pressure is dependent upon what the pressure plate manufacturer's specifications are.


Are there any drawbacks to high clamping pressure plates?
Generally speaking, the higher clamping pressure of the pressure plate, the higher pressure you induce on your crankshaft thrust bearings.


What is the most transmission friendly clutch?
The OEM organic clutch is by far the easiest on your transmission. This is due to the lighter clamp loads of the OEM pressure plate and the organic clutch material. Organic materials, which are bound by resins, will almost always loose friction when they get very hot. This is because the resin melts and becomes almost like a lubricant rather than a bonding agent. Any increase in clamp load or clutch material coefficient of friction will increase the shock load to your gears.


What clutch will hold the most power?
Generally speaking, one that has:
a. Highly sprung pressure plate. The more clamping force the pressure plate exerts, the better it will grip.
b. High coefficient of friction clutch material. The higher the coefficient of friction, the better it will grip.
c. Increase the amount of surfaces. This can be accomplished by going to a twin or triple disc design.


What about a "Stage 1 clutch"?
Stage 1, 2, 3, etc. clutches are just a marketing tools. Some manufacturers have them, some don't. While a staged clutch may suit your application.


How hard is it to install a clutch?
Allow around five hours for install time. Professional installation, depending on your area, is around $300. This is one vehicle modification that should be farmed out to a professional unless you have the right tools/equipment and are mechanically skilled.


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Flywheels - Lightweight vs. Heavyweight
To answer the much heated and most debated question. Should i get a light, or should i stay with stock? Let me try to explain this as easily as possible and let you decide.

Rotating mass takes energy to spin it from one RPM to another. Therefore, it takes power from the engine that could otherwise be used to accelerate the vehicle.

The significant measure of rotating mass is called the mass moment of inertia. To keep it simple, weight is bad, but weight farther from the center-of-rotation is much worse. The mass moment of inertia is measured by the mass (weight) multiplied by the distance between the weight and center of rotation squared. For instance if you had a weight of 10 pounds mass, 5 inches from the center of rotation, its' mass moment of inertia would be 10 lb x 5 in x 5 in = 250 lb in^2. That same 10 pounds only one inch from the center of rotation would only have a mass moment of inertia of 10 lb in^2 (96% less). This is why lower diameter flywheels are an issue and heavy larger wheels can have an effect.

When you were a child you may remember playing on hand pushed marry-go-rounds. Kids would stand on them and other children push to get them spinning. You may also remember that it was much harder to push when there were more kids on the marry-go-round and they stood near the edges.

Now for the stock flywheel. I am told the stock flywheel has a mass moment of inertia of 280 lb in^2 and I used this value in these calculations. Let me warn, the effect of rotating mass is not constant for RPM or road speed. In other words, the effect in 1st gear is different than second, and in any gear the effect changes with speed. This is why, if anybody quotes a given horsepower savings measured on a dyno, it is not accurate because chassis dynos DO NOT simulate accurate transients. They measure horsepower at the wheels just fine, but they can not measure the effect of a lightened flywheel, tires, or wheels. They will measure a difference, it just isn't accurate. But it is easy to calculate the difference.

From simple calculations the stock flywheel (280 lb in^2) takes 10-20 HP to spin it while accelerating in 1st gear. In second gear it takes about 5 HP. In 3rd gear it takes 2-3 HP. Therefore, if your lightweight flywheel had half the stock flywheel mass moment of inertia, you could save half the above values. To me, this would be more significant in a 1/4 mile run where the launch and 1st gear is very important. On a road course, not as important.

You might wonder why 1st gear is so much larger? The most stock engines (B or D series) spins from idle to REV LIMIT in less than 4 seconds (give or take) in 1st gear. It takes a lot of power to spin this mass to high RPM very quickly. In 4th gear, the stock flywheel takes 10-20 seconds to go from MID to REV LIMIT RPM, therefore, much less power required.

A transmission can be thought of as a fulcrum and lever in a car. First gear has a really long lever; second gear has a shorter lever, etc. The lever represents the mechanical advantage that gears give your vehicle. When your car is moving, you have two factors that are present during acceleration, one is driveline losses, which are constant and the variable, which is vehicle weight and the mechanical advantage supplied by each gear. We know that within reason, vehicle mass is a constant. Now imagine if you reduced the driveline loss from 45 to 35 with the use of a lightweight flywheel. Since the engine has less drivetrain losses to compensate for, this means the "gained" horsepower can be applied to moving the vehicle mass. Using mathematics, one can realize that the higher you go up in gears, the less effect that a lightened flywheel will have to the overall equation.

While the performance characteristics of a lightweight flywheel seem to be the perfect solution, there are compromises. Low end performance is affected. This usually means that higher revs are necessary for smooth starts due to the reduced rotational mass. For drag racers, this can be a BIG issue.

-xproductionz.com


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Nitrous 101

The purpose of this thread is to post all basic and pertinent information about using Nitrous. Everybody post stuff up as you think of it. Hopefully this thread will help forum member's when they first start researching Nitrous and it will be a good reference to anyone else who may need it.


The type's of Nitrous Kits:

Wet Nitrous Kit:

Wet Nitrous kits have a Fuel Solenoid and Nitrous Solenoid that allow's for Fuel to be sprayed along with Nitrous. The Fuel mixing with the Nitrous allow's for the motor to avoid running lean due to lack of Fuel and it help's to prevent detonation. This is why you can typically run a larger wet shot on stock fuel delivery component's then a Dry shot.


Dry Nitrous Kit:

Dry Nitrous kits have a Nitrous Solenoid that allow's for a specified amount of Nitrous to spray without the adding of Fuel. This type of kit relies on stock Fuel delivery (i.e. – Injector's, Fuel Pump, etc….). When increasing shot size on a Dry kit it is necessary to upgrade Fuel delivery component's to avoid detonation and eventual engine failure due to the motor running a lean condition.

Direct Port Kit:

Direct Port kits run both Nitrous and Fuel to nozzles that have been tapped into the intake runner's of the Intake Manifold. A Direct Port allow's you to run a much larger shot then a Wet or Dry kit. And it also allow's for a much more equal distribution of Nitrous to all the cylinder's.


Nitrous Accessories:

Bottle Warmer - Heat's the Nitrous bottle until the Nitrous inside reaches a specified pressure at which the Nitrous will produce power at it’s full potential.

Purge Kit - Allow's the driver to "Purge" the Nitrous line's of all Air and Nitrous that was not completely used when the system was last used.

Window Switch – This device will only allow your Nitrous to spray between a driver specified “Window” in the rpm range. For example, if you select a beginning of 3500rpm and an ending of 8000rpm then the Nitrous will only spray between 3500 and 8000 rpm’s. This tool can be used as a fail safe for lower shots making sure that you do not engage the Nitrous at to low of an rpm. This is of greatest use to someone who runs a larger shot, particularly because the driver can make sure that they set the end of the window at a prior rpm to the fuel cut, so that they don’t accidentally continue spraying after they’ve reached fuel cut.

Bottle Blanket – Insulate's the Nitrous bottle to help maintain consistent temperature and pressure.

Blow Down Tube – This is an externaly vented tube that runs from the Nitrous bottle to the outside of the vehicle. In the event that the bottle becomes to pressurized, a valve open's releasing the content's of the bottle through the tube. This is required at some track's in order to use Nitrous.

Nitrous Pressure Gauge – This gauge allow's you to monitor your bottle pressure.

EGT Gauge – (Exhaust Gas Temperature = EGT) This gauge allow's you to monitor your Exhaust temp. This is a good indicator as to wether you need to let your motor cool before use or if it is alright to use your Nitrous again. Helpful in prevention of overheating and overworking your motor.

A/F Gauge – (Air/Fuel) This gauge allow's you to make sure that when using Nitrous you do not run lean.

Progressive Controller - This allow's a gradual increase in Nitrous as your rpm's increase. For example and keep in mind, this is hypothetical and not necessarily the rpm that you have to switch shot size at. To start you are spraying a 50 shot off the line, once you reach 4k rpm's you are up to a 75 shot, once you reach 5.5k rpm's you are up to a 100 shot and by redline you’re spraying a 125 shot. This “Progressive” increase in Nitrous allow's you to run a large shot without putting sudden strain on your engine’s internal's.

WOT Switch - (Wide Open Throttle = WOT) This switch will only allow Nitrous to be sprayed when the throttle is wide open.


Miscellaneous Information:

Recommended Bottle Pressure:

1000 -1200 psi - Bottle is fully pressurized and will produce the best result's.

600 - 700 psi - Bottle is nearly empty(So go refill it)!!

Timing:

Retarding timing according to the shot size is necessary to avoid detonation. Below are the suggested timing retard settings according to the shot size. It is always a good idea to referance your kits manufacturer’s suggested timing information, but below is a general guideline of typical recommendation's.

50 shot - 0-1 degree timing retard
75 shot - 2 degree timing retard
100 shot - 3 degree timing retard

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More Nitrous 101

There are many different philosophies and opinions regarding the proper nitrous system. Please e-mail if you have positive question or suggestion that could improve safety or contribute to quality and performance.

How Nitrous works-Nitrous Oxide, Ny-Trous plus, NOS, Spray, Juice, Shot, Squeeze, Bang, Blow, Jizz, Laughing Gas.

It is a colorless, odorless gas composed of two (2) nitrogen atoms bonded to one (1) oxygen atom. The scientific abbreviation for nitrogen is N, and O for oxygen. The proper abbreviation for one nitrous oxide molecule is N2O. This where the familiar phrase “N-2-O” comes from.

Nitrous Oxide is an oxidizer that is used as a carrier for oxygen. Mixed with the right ratios of fuel, and fed into the intake, it provides additional combustible material into the cylinders, creating more power. There are many ways to get the nitrous and fuel into the engine, the following describes typical applications that have proven successful.

The Basics-The nitrous is compressed to high pressure (900-1100psi) in a tank, in liquid form. From the tank (typically fastened down tightly in your trunk), a hose runs up to the engine bay. From there, an electrically controlled (like, by a button you push) valve called a solenoid is used to release the nitrous into the motor when you request it. At the same time, a fuel line in a "wet system," is controlled by another solenoid, and releases fuel into the motor. This provides the basic mechanism for the nitrous system.

Wet -vs- Dry-You may have heard the terms "wet kit" and "dry kit.".

A "wet system" is a nitrous system that mixes both nitrous and fuel, and feeds it (in a "Spray") into the intake. A "dry system" only feeds nitrous into the intake, and tricks the existing fuel system to add the fuel.

As mentioned, there are several ways to feed the nitrous and fuel into your motor. Here are brief descriptions of them.

Throttle Body Plate-This is a 1/2" thick plate that's mounted between your throttle body and intake manifold. Both nitrous and fuel lines are connected to it (so it's a wet setup) and the plate combines them and sprays into the intake.

Fogger Nozzle-A nozzle can support either a single line for nitrous, or a pair of lines for nitrous and fuel, and sprays a fine mist into the intake.

Direct Port-The ultimate setup- each port is tapped and threaded specifically for a nozzle at each cylinder. nitrous and fuel lines to spray directly into the cylinders. This setup typically provides the most horsepower for extreme race applications.

Triggering the System-Of course, you don't want the system to be running all the time - a 10lb bottle will last you less than a minute, if it's open. Typically, you want the system triggered on while you're at the track, at WOT (wide open throttle), and at relatively high rpm's (see "Safety" for why). To make that happen, you'll typically want to wire, in sequence, several switches. I won't describe the specific wiring here, but you'll have some or all of the following:

1) Arming (On/Off ) switch. 2) WOT switch is a micro switch installed on the throttle system, that activates the circuit only when your foot is on the floorboard. 3)pushbutton in the car, probably on the shifter 4)"Window Switch" (see "Safety" for details) that closes the circuit only when the engine RPM is between a certain range (like 3000-6000) that you decide is acceptable 5) Fuel Pressure Safety Switch

Nitrous Controllers-The system to trigger described above is a basic "single stage" setup. The nitrous is either on or off, and when it's on, the full volume dictated by the jets is sprayed into the engine. There are other applications that are full race or multiple stage nitrous system that require more detailed management at higher rpm, with time-based systems, which delay the nitrous flow for some time after you launch, etc.

These Nitrous controllers are a great addition to any nitrous system and can help to safeguard the engine from Lean-Condition.

Safety-Use all the safety mechanisms you have available. They are cheap and very effective. Components such as Fuel Pressure safety Switch, Rev limiters, EGT sensors, Window switches, etc. are relatively inexpensive ways to protect your investment.

What Can Go Wrong?-Well, a lot can go wrong, but hopefully you'll have adequate safety mechanisms built in to protect your motor when it does. The main thing that can go wrong is adding nitrous into your engine without compensating fuel. This extreme lean condition is disaster for the engine, and you're not likely to get a second chance - at least with the same engine. Conversely, adding extra fuel without nitrous is not particularly bad for the engine, so you can imagine, it's safer to start with the car running rich (too much fuel), then lean it back from there. Some examples of problems you might encounter include:

Ignition RPM limiter-The rev limiter is implemented by cutting the signal to the fuel injectors so the cylinders have no combustion. If you're running a dry system, which depends on the fuel injectors to provide compensating fuel for the nitrous, losing fuel this way is the ultimate disaster. An after market ignition will typically implement the rev limit by cutting off spark rather than fuel, which is a much safer implementation of the rev limit. Typically, you'd get your stock PCM programmed to set the rev limit up higher than you'll ever expect to go (like 7000RPM), and use the setting on the after market ignition as your actual rev limit.

Window Switch-This electrical device provides an open or closed circuit based on the engine being between two RPM values (hence "window") that you chose, so that you'll only flow nitrous in this range. Why would you do that? Well, for two very different reasons.

1) At low RPM, think about what's going on: you're spraying nitrous into the intake at a constant flow. That is, the nitrous bottle and solenoids have no idea what RPM you're at, and they're just pushing it into the intake at a constant volume. Inside the engine, though, the nitrous and fuel combination is being sucked into the cylinders during every stroke. The net result is that at low RPM, you're getting far more of the mixture into the cylinders. At 3000 RPM, for example, you're getting twice the amount as at 6000 RPM. So, you can imagine that running nitrous at, say 1000 RPM, is far more stressful on the motor as at 3000 RPM, and typically causes a "nitrous backfire" - meaning that the nitrous/fuel combination can explode in the intake manifold (rather than the cylinders) - a bad thing. So that's why you don't want the system triggered at low RPM.

2) At high RPM, the situation is easier to explain. Given the discussion of the rev limit above, you may just want the nitrous system to cut off before hitting that rev limit. If you've got a stock ignition, you certainly want a window switch. If your rev limit is implemented by an aftermarket ignition, it's perfectly safe for the motor to run nitrous during the rev limit. It's not particularly easy though, on your transmission or clutch to have all that power during the shift, which may be a reason to keep the window switch set a bit before you shift.

Fuel Pressure Safety Switch (FPSS)-This is a device that's plumbed into the fuel system, and provides an open or closed circuit based on availability of fuel pressure. It can be used in the triggering circuit to make sure the system isn't on when you've got a fuel problem. Typically, you only use it to switch off the nitrous solenoid; turning off the fuel solenoid as well can start a cycle of switching the solenoids on and off while the pressure raises and drops in the fuel system when you're switching the solenoid on and off. Let the pressure build up in the fuel lines when you open that solenoid, and when it's high enough, the nitrous solenoid will open. The switch can be used whether you've got a wet or a dry system. You can adjust the pressure at which it triggers by using an allen wrench on the back of the switch (loosen the screw lowers the pressure threshold).

You want to set the pressure on the FPSS, such that if the pressure drops about 10psi the nitrous system will shut off. On a wet EFI system, this will be around 33psi, and on a dry system I'd leave the switch just above stock, say 45psi.

To set the threshold pressure, you've got a few options"

Connect enough plumbing so that you can have the FPSS installed at the same time as a fuel pressure gauge. Turn the key on to pressurize the fuel system, then turn it off. As the fuel pressure bleeds down, monitor the continuity across the FPSS contacts (disconnect them from the rest of the nitrous system) and when the pressure reaches the level you're interested in, adjust the screw on the back so it just balances back and forth between the continuity signal.

You could use an air compressor, with the appropriate fitting for the FPSS. Remove the FPSS from the car, and thread it onto the compressor. Set the compressor for the pressure of interest, and measure continuity as above.

If you can't do option #1 above because you don't have two available ports, first thread in the pressure gauge, and cycle the key. Then time how long it takes for the pressure to bleed down to the correct level. Then disconnect the pressure gauge, install the FPSS, and do the process against the clock rather than the pressure.

Timing Retard-A nitrous/fuel mixture increases the burn rate in the cylinder, and typically adding a few degrees of timing retard is recommended for safety. A rule of thumb is two degrees per 50hp of nitrous, but this will also reduce the power generated. When I tune my system, I monitor engine knock, and retard the timing only enough to eliminate the knock, which is usually about one degree per 50hp. At the track, under harder conditions (actually pulling the weight of the car, possibly higher outdoor temperatures, etc) I'll add a degree of retard.

High Octane Fuel-High octane gas (e.g. 100 or more, unleaded) will also slow the burn rate in the cylinder. This will provide another way, similar to retarding timing, to avoid knock. I only use nitrous on a 50/50 mix of 92 octane pump gas and 100 octane racing gas. Make sure it's unleaded, of course, or you'll destroy your O2 sensors.

By the way, watch out for Octane Boost claims. Typical claims are "8-10 points of octane boost for a tank of gas." You should be aware that these "points" are tenths of a point of octane as you'd purchase at a gas station. So the above example will raise your octane from 92 to 92.8 or 93, not 100-102 as you might think.

Don't assume that if high octane fuel helps on nitrous motors, that it'll help your naturally aspirated motor too. A naturally aspirated motor is tuned for a particular octane of gas; adding more doesn't help one bit. Save your money.

Nitrous Filter-A simple part, but essential in any nitrous system. This filter is added in-line to your nitrous line, between the tank and the solenoid. Install it as close to the solenoid end as is convenient. It will trap any small particles that may come through the line, much like a fuel filter. A common solenoid failure is due to some particle jamming it open.

Fuel Systems-Your fuel system is the most important part of the system. As I hope is clear by now, the worst scenario in a nitrous system is a lean air/fuel mixture. The solutions to a good fuel system depend on the type of nitrous system you're using.

On a wet system, you simply need to ensure that your fuel system can supply adequate fuel, at standard (~45psi at WOT) pressure. A stock f-body fuel pump can usually supply enough fuel for around 450 total horsepower to the motor; any more and you want to get a larger pump. Much more than 650hp and you'll want larger fuel lines as well.

On a dry system, not only do you want adequate fuel like the wet system, but on an typical setup the fuel is added by raising the fuel pressure, which forces more gas through the injectors. In this scenario, it's typically recommended that you replace the stock fuel injectors with better quality (not higher rating, just better, like Bosch) injectors. These injectors are able to handle the increased fuel pressures necessary.

Spark Plugs-Generally you want to use copper spark plugs or iridium as opposed to the stock platinum ones. You also want to reduce the gap from the stock 0.050" down to 0.035"-0.040". I've received a couple notes on why you use a smaller gap. "The reason you want a smaller gap is because of ionization. If you change from the typical air (78%nitrogen, 21% oxygen)/fuel ratio, a given gap requires more energy to ionize the mixture, resulting in less energy in the spark, if you even get a spark. You could also increase the coil voltage instead of decreasing the gap, but I think using a smaller gap would be preferential since the spark time will be smaller." and also this message: "The reason that you will close the gap on your spark plugs is because when nitrous is added, it raises the cylinder pressure, much like a supercharger. Therefore "blowing" the spark out. When you close the gap it cannot put out the spark as easily."

Testing Solenoids-I mentioned failed fuel or nitrous solenoids doing damage. Some of the issues here may be hard to cover with only other safety devices. I recommend you wire your solenoids with spade clips, so you can easily disconnect them, and test them on a regular basis. Simply disconnect them from the rest of the wiring, then ground one side, and connect the other side to 12V, and listen for the click-click to make sure they open and close. Some folks will also use two nitrous solenoids, in-line, which will ensure that both would have to fail before the flow would fail to stop. Of course you still need to test this setup, to ensure one isn't stuck open.

Tuning-All of the kit systems will come with a couple tuning setups, labeled "50-shot", "100-shot", etc. These are tuned to provide 35, 50, 75 or other horsepower amounts, usually measured at the crank (i.e., measured on a chassis dyno you'll get a bit less). I consider these a starting point, and certainly good for your first passes (hopefully you'll make these with the lowest power, until you tune the system up). Once you've got the system installed and functional, though, tuning it is paramount, before running any serious power through it. I really recommend you do this tuning right away, even though the temptation will be strong to just go out and enjoy the power. This is the time you're very likely to do some serious damage to the motor, it's important to get it set up right.

Getting Started-I'm not going to go through a bunch of details on tuning here, other than to mention some ideas. You've got a plumbing system to test, as well as an electrical system. You'd like to test each component of both systems, to verify that it's correctly doing it's job. I suggest doing most of this in your garage, with the nitrous and fuel lines removed from the intake, and pointing (or held) into a rag. Keep in mind the nitrous line will give a good kick under pressure, so don't just leave it loose to whip around. You can test your WOT switch easily enough, your window switch (maybe set the window range at a lower rpm for the test, so you don't have to rev up to your red line). To test your fuel pressure switch, you'll need to verify it's got a closed circuit when the engine is running (showing adequate pressure), but you'll also want to verify that it opens the circuit as fuel pressure drops. There are a couple ways to do this. On my car, the fuel pressure bleeds off at about 2psi per hour. So if I switch the engine off, I can use an ohm meter to check continuity across the FPSS connections, and within a couple hours it should switch off. You can also test the FPSS on an air compressor, by generating the pressure you want for the FPSS, and monitoring that it switches at the right point.

For the plumbing, you of course want to verify that there are no fuel or nitrous leaks in the system. You should be able to leave your nitrous bottle open for hours without losing bottle pressure. On the fuel side, of course a fuel leak may be the most disastrous possibility, so check this first by pressurizing the system (turn the key to "acc" but don't start the car) and feel around all the fittings.

I haven't listed all possibilities, but hopefully given you an idea of where to start testing. Once everything seems to check out, put in a set of 50hp jets, and move out on the track.

Jets-All nitrous systems use "jets" inserted in the fuel or nitrous lines to limit the flow. These jets have openings of a specific size, measured in thousandths of an inch. So a "35 jet" is a jet with a hole drilled 0.035" through it. Increasing a nitrous jet size will make the system run more lean, increasing the fuel jet size will make the system run more rich.

There's also a good web site with a jet size calculator on it for a wet setup (where you're metering the fuel and nitrous yourself). It will give you jet sizes based on desired horsepower, fuel and nitrous pressure. I recommend you use these as a target, maybe start a bit richer than shown.

I don't have information here on the use of a jet to apply vacuum pressure to a fuel pressure regulator, as in the NOS 5176 kit. The use of jets for this purpose, and calling them "fuel jets" is NOT related in any way to the normal use of fuel jets in a wet system, and I'm not aware of algorithms that would allow you to select these jets in combination with nitrous jets, to create a certain amount of horsepower. Contact the nitrous kit vendor for recommendations.


Scanner Tuning-A PCM scanner (Diacom, Autotap, etc) is crucial to successful tuning of your nitrous system. I run most of my nitrous passes while logging with an Autotap, and also use it at the dyno. You'll be monitoring the oxygen sensor voltages, knock, etc, and adjusting the jets to provide the best combination. Note, though, that the stock oxygen sensors are not particularly good, and a wideband O2 sensor (say, at a dyno) is much better to use if you have access to one. Typical O2 values should be around 860-880mv (higher is richer) when running the motor normally aspirated, and I try to tune mine to 900-940 on nitrous. As mentioned above, you'll adjust jet sizes up or down to enrich or lean out the mixture. You'll probably see some knock during a shift, but should see none otherwise. You can add timing retard to reduce knock.

Dyno Tuning-Doing your scanner tuning at a dyno provides another benefit, since you can see the power the engine is generating, while you tune the system. It also makes the whole tuning process easier than racing up and down the track, swapping jets in the pits, waiting in lines, etc.

How much can I run?-On a stock V8 motor, 150hp appears to be the limit. 125hp is probably a "safe" setup, assuming it's working well. A built, forged motor can take quite a bit more, 200-250hp is probably reasonable, but you'll be going to direct port if you want more power. On a six-cylinder motor, 75-100hp, while stock 4 cylinder can take from 35-75hp. These seem to be the highest "safe" setups. Of course, I use the term "safe" very loosely here, to mean that folks have run this amount of nitrous for quite a while without blowing up their engines.

Miscellaneous Options

Purge-Most nitrous systems are build with a purge feature. The purpose of a purge is to get liquid nitrous oxide up to the front of the car, filling the hoses with nitrous rather than air. To do this, another solenoid is used, but rather than shooting the nitrous into the motor, it's usually shot up over the hood, or out of the grill so you can purge until it creates a nice fog. It also looks real cool . Of course, no fuel is used during a purge.

Bottle Heater-It's virtually mandatory that you install your nitrous system with a bottle heater, which is used to raise up the temperature of the bottle, and therefore increase the pressure at which the nitrous is delivered. If you don't use one, your pressure will quickly drop and won't supply the volume of nitrous your vehicle was tuned for.

Remote Bottle Opener-Normally, your nitrous bottle should be kept closed, with no pressure in the nitrous lines. But when you're lined up against that guy that just looks a bit too fast, you'd hate to say "excuse me, do you mind if I hop out and open my bottle in the trunk?". Easy solution, get a remote bottle opener! Most vendors have such a device, which allows you to open the bottle electrically via a switch on your dash.

Collateral Damage-You can break tons of other parts on your car by running nitrous, or any other large power addition. Running slicks at the track will just accelerate the damage. Here are a few things to keep in mind.

Clutch-The huge torque spike at low rpm's is particularly hard on clutches. I had to buy a new clutch as soon as I made my first pass with nitrous on slicks. Keep in mind, on a manual transmission car, you're likely to need one too.

Rear End-Not unique to nitrous, but certainly a common failure on high horsepower cars, is the rear end. A 4th generation f-body, with a stock 10-bolt rear end, is not going to last long on nitrous. Plan for an expensive (~$2,000) upgrade at some point.

Tires-With all the extra power, you'll have trouble hooking up with any traction, especially on street tires. You'll probably have to use drag radials at least, or slicks if you're adding any significant power.

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I got some other stuff too like how to build a GSR block.. Doing a k20swap.. Service manuals and so forth

SEN_ONE

iTrader: (11)

Not bad, not bad at all.

LT2004ever

iTrader: (2)

nice , but i think the NO_2_ stuff was already explained somewhere

xproductionz

iTrader: (14)

Heres a nitrous calculator to go along with the NO2 stuff

Nitrous Oxide Jet size and HP Calculator nos n2o

TRIZ

iTrader: (14)

Good stuff. I read so much, man- thats a hell of a read, but I learned a bunch of stuff that I didnt really understand too much before. You posted the HP calculator, but then earlier u said the true measure of performance was torque. Good stuff.

DDragon7

Good read on the technical side of things.

simplicated1979

nice write up...well explained about a lot of stuff..

xRiCeBoYx

iTrader: (22)

holy crap.. nice post man

Valdeezy

Thats alot of reading but alot of good info good job.

xproductionz

iTrader: (14)

Ttt....

xproductionz

iTrader: (14)

up and away

slowwhitecivic

iTrader: (4)

good thing to read since i didnt have nothing to do lol