I found this info on
ef-honda.com posted by
SthPerformance I found it very informative and thought it would be a worthy addition to T-J.
What is Octane ??-
To explain it simply, Octane is commonly know as a measurement of how much heat a given fuel can withstand before it ignites itself. When crude oil is removed from the ground and sent to be refined it is seperated into differant hydrocarbons. The most common ones are known as methane, propane, butane, pentane, hexane, heptane and octane. Some of these are fuels used on an everyday basis by many of us. Each one of these fuels has a differant point of which they become vapor or better known as their boiling point. This is the process that is use to refine the crude oil and seperate the carbons into many of the differant fuels mentioned. As well as each one having a differant boiling point; they also have a differant temperature of which they ignite themselves. Out of the fuels listed, Octane can withstand the highest temperature before it detonates. The octane rating we see on the pumps is the percentage of Octane that is present in the fuel. Most of the remaining percentage of fuel is Heptane. This percentage became known as the "Octane rating." Heptane has an Octane rating of 0. In the early part of 1900's during WWI there was a subsutite found that would artifically increase the "octane rating" of fuel without an actual increase in the percentage of Octane present. This subsutite is known as Tetraethyl lead. Fuel with Tetraethyl lead is simply known as leaded fuel.
Why leaded or unleaded??-
As explained above Tetraethyl lead was added to fuel as a subsitute during WWI to increase the Octane rating of the fuel. Tetraethyl lead was commonly used until the mid to late 1980's. The additive was removed from the fuel because lead is toxic to animal and human life. During the Late 70's and early 80's it was common to see fuel with the Octane rating of 104 at the pumping stations. The removal of lead from fuel drastically increased the cost of fuel. This increase in cost was because more extentive refining was required to obtain a higher Octane percentage or rating without the addition of lead. It also reduced the amount of emissions from the vehicle by utilizing catylitic converters. Catylitic converters can not be used with leaded fuels. The lead will clog them in minutes during operation.
Is higher octane fuel "The good stuff" ??-
The common answer to this question is yes, many cars on the market now require a higher Octane rated fuel to operate properly. Your vehicle owner's manual will designate what Octane rated fuel is required for your perticular model. Fuels that are on the market now that have a higher octane rating and actually consist of a higher percentage of Octane, not a subsutite that increase the Octane rating. Although, because the fuels octane rating is lower does not mean that it is of lesser quality than one of a higher Octane rating. You may say define quality.
The quality that is being referred to is the cleanliness of the fuel in regards to heptane present. So, the only main differance is not the purity; one can just withstand more heat before igniting itself than the other.
Is it worth the extra money for higher Octane fuel ??-
In some cases, YES !! But in others, no it is not required. Consult your owner's manual to see what the recommended Octane rating its for your model car. Performance cars tend to require a higher octane fuel than commuter cars. Cars with high mileage should use fuel that has a higher octane even though an owners manual may say it is not required. An engine's compression ratio may increase with age. This occurs when carbon deposits build up on piston domes and combustion chamber walls. An engine's compression ratio directly reflects what octane fuel is required. If a fuel is used that has a lower Octane than is required severe engine damage may occur in a short period of time. Pinging is commonly heard when the fuels octane is to low. This is really bad. If this occurs fill up with the higher Octane fuel as soon as possible. If you have a full tank, get some Octane booster at your local autoparts store.
Piston Deburring Tech Info-
Boost is nothing but compressed air that is forced into the engine. Boost can increase engine HP. Although, there are several drawbacks from boost. Anytime a gas is compressed heat is a by product. This also works in reverse. When a gas is decompressed it reduces temperature. Such as Nitrous oxide. When it is decompressed to bar it is approximately -130 degrees.
Obviously compressed air has a considerably higher oxygen content than non compressed air. That extra oxygen allows for increased fuel to be added to the combustion chamber resulting in higher peak cylinder pressure on the power stroke. When tuned properly higher cylinder pressure directly relates to more HP. There are two different types of compression. Static compression and effective compression. Static compression is the division of the cylinder stroke volume by the combustion chamber volume. Effective compression is measured by taking bar ([14.7lbs/square inch]which is absolute atmospheric pressure)and dividing it by the how many pounds of boost the engine is under. Lets use 10lbs in our figure. 10 / 14.7 = 0.68 Add one; 0.68 + 1 = 1.68 Then multiply by the static compression. 1.68 X 10 = 16.80. As you can see the engine's compression ratio is 68% higher than it's static at 10 lbs of boost. This is a very important fact to realize.
During the compression stroke of our engine the air and fuel mixture is compressed to 10 times it's size. Remember we learn earlier that when a gas is compressed heat is a by product. This is where the fuel's octane comes into play. Octane is a rating of how much the fuel can be compressed before it ignites itself via the heat from compression and combustion chamber temps. A fuel that is suited for a 10:1 static compression engine may not be suited for an engine that has a higher effective compression ratio. The more the mixture is compressed the more heat that is generated and in turn the higher octane fuel that is required. High cylinder temperatures have an effect on the compressed gases temperature. Cooler cylinder temps enable more compression or more boost to be had for a given octane fuel.
For those who dont know the suspension facts as well as others maybe this info will be able help you understand the facts of a suspension...
CAMBER: Camber is the angle the wheel deviates from perfectly vertical when looked at from straight ahead. Positive camber would have the top of the wheel inclined outwards, away from vehicle center, while negative camber has the top of the wheel leaning inwards to vehicle center. Contrary to popular belief, any and all camber angles hurt tire adhesion to the road, and for one obvious reason. Tires create the most grip when they put the biggest footprint onto the pavement possible, and any significant camber angles shrink the all important contact patch. The reason people associate negative cmaber with good handling is because as body roll occurs in a corner, positive camber is naturally imparted to the outside wheels. The suspension's camber angle at static ride height (plus it's camber curve, see below) will determine whether the wheel goes into positive camber during body roll, or simply balances out to zero camber. So just know that ideally we want zero camber at all times, but like most things automotive a compromise must be struck: dial in a bit of negative camber at static ride height for the least amount of positive camber possible at maximum effort cornering.
CAMBER CURVE: A camber curve is created by most suspensions because camber constantly changes as the suspension is compressed and expanded. Generally speaking, any independent suspension will increase negative wheel camber as it compresses, and increase positive wheel camber as it expands. Hence, the camber curve lets us see what camber angle the wheel will be at with the suspension at a given amount of compression or expansion.
CASTER: Caster is the angle of inclination between the mounting point of the spindle at hub center to the upper A arm (in cars with upper A arms anyways), when veiwed from the side of the car. If you drew a vertical line through the hub center, then another from this point to the spindle's mounting point on the upper A arm, you would get rearward biased angle on any car (called positive caster angle). This design concept is critical for high speed directional vehicle stability, camber gain during steering, and also plays a roll in anti-dive characteristics under braking.
TOE: Toe is the amount the tire's point inward or outward from dead ahead when the steering is perfectly centered (viewed from directly above the tire). Toe is measured in inches (usually very small increments of inches to be exact); toe-out indicates the wheels point slightly away from vehicle center in a straight on path, while toe-in indicates a slight bias towards vehicle center. Zero toe would be a case where the wheels point dead ahead when the steering is centered. Toe plays an important part in straight line stability and vehicle turn-in characteristics. Toe-in gives makes the car easier to keep pointed straight during normal driving and under heavy braking, while toe-out makes the vehicle feel more eager to enter corners but will cause directional stability to suffer (and stability under braking to suffer greatly).
TOE CURVE: Just like camber, toe amount changes as the suspension undergoes movement. Suspension designers generally take full advantage of this and design the suspension to take on reduce toe amounts as the suspension compresses, thus allowing the vehicle to remain directionally stable during normal driving yet more eager to change direction under braking.
SET BACK: Measures the difference between wheel location from one side to the other relative to each other (when viewed from above). Let's say we were to draw a line through the center of the car (from fore to aft), then draw a line perpendicular to this beginning at the leading edge of, say, the left front tire. If the right front tire didn't precisely touch that line (let's say for simplicity it was 1/4" behind that line), you would have a front axle set back of 1/4". Basically this just tells you how dead on the front wheels are located relative to each other when viewed from the side of a car on an alignment machine. If the set back were a fairly large value (say nearly 1/2-1"), it's probable that something in the suspension or frame has been bent.
SAI (Steering Axis Inclination): This is a measure of the steering's pivot axis vs. the tire's true pivoting axis (as viewed from the front of the car). Virtually every suspension design doesn't actually have the steering system pivot the wheel in a perfectly vertical axis, because the mounting point of the steering's tie rod to the spindle is usually further out from the center of the vehicle than the upper mounting location of the spindle to the upper A arm (in your suspension). In other words, the steering system pivots about an axis that is tilted inwards towards the center of the car at it's upper mounting location. However, the wheel pivots about an axis that is perpendicular to the ground (imagine a second line drawn vertically though the center of the hub). The difference in angle of these two lines, one being the steering axis and the other being the wheel axis, is called the SAI. Whenever the SAI is out of spec, it's usually due to a bent suspension component, as this concept is centered around suspension hard parts and their mounting points to the chassis of the car.
INCLUDED ANGLE: Ok, so I lied! When I said the wheel pivots about an axis perpendicular to the ground, I wasn't being perfectly accurate for most any independent suspension design. Our wheels almost always have a camber angle (hopefully a small negative angle at normal ride height), and this throws off our nice little concept of SAI. To get a really accurate idea of the difference in pivoting axes between the steering system and wheel, you need to take into account the camber of said wheel. So, say if you had an SAI of 15 degrees and a negative camber on the wheel of 1 degree, you would get an included angle of 14 degrees. The wheel is canted inwards 1 degree from our previous true vertical measuring point, so this concept will give us a truly accurate idea of the angles everything will be pivoting on at normal ride height.
SCRUB RADIUS: The difference between where the SAI line and the vertical wheel centerline intersect the ground (as viewed from the front of the car). A vehicle is said to have a postive scrub radius if the SAI line falls closer to vehicle center than the tire, and a negative scrub radius if it falls outside the tire centerline. Scrub radius is important to both vehicle stability under braking and acceleration, plus steering feedback during at the limit adhesion. A negative scrub radius hurts steering feel (most fwd cars have either zero to negative scrub), but keeps the steering wheel from yanking around when one of the steered wheels loses traction (a positive scrub radius can yank the wheel out of your hands when only one steering wheel loses traction during a turn, which is of course a bad thing).
ACKERMAN STEERING: A design concept which allows the inside wheel of the steered axle to travel a tighter arc than the outside. When one thinks about a vehicle turning, it becomes obvious that for the front end to maintain optimal traction, the inside wheel in the turn always has to be making a slightly sharper turn than the inside wheel. If both turned an equal path, the two tires would effectively be following different curves around the same point and wasting a whole lot of grip in the process. So ackerman steering geometry is created to allow the inside wheel to turn a somewhat tighter arc than the outside, maximizing traction during a turn. Also, increased ackerman will enhance toe-out during cornering, allowing the vehicle to become even more nimble in changing direction. Ackerman is however, one of those things the average Honda enthusiast never need worry about, I just figured I would mention it since we are on the topic of aligment.
COIL SPRING: Since almost every car uses coil springs these days, you don't need to know about anything else. A coil spring is exactly that, a coil of wire that takes a certain amount of energy to compress and expand. The energy it takes to compress the spring is what determines the srping rate, which is usually described in lbs/in or in kg/mm. A spring that is decribed as having a rate of 300 lbs/in takes 300 pounds of force to compress it 1 inch.
LINEAR VS. PROGRESSIVE RATE COIL SPRINGS: A linear spring has a straight compression rating, meaning that for our earlier example it would take 300 lbs of force to compress the spring every inch throughout it's total travel. Say the car weighs 300 lbs at one corner, well the spring at that corner would be compressed one inch once installed. For each additional 300 lbs of pressure put on the spring, it would compress an aditional inch until it reaches minimum height. If the spring is termed progressive rate however, this rate changes as the spring is compressed. Many springs are progressive rate because it allows the suspension to be softer initially (making ride quality better) but stiffening up as the amount the spring is compressed increases. This allows you to make the spring fairly soft at smaller compression while making it stiff enough at bigger compression amounts to accurately control wheel & suspension movement when you are hauling ass. Progessive springs usually allow the car to ride & handle better if they are properly designed, but the added complexity to designing and making them work properly also increases the possibility of screwing things up. For these reasons linear springs are often still used for our cars, but if you can find good progressive rate springs from a reputable manufacturer they will enhance both ride quality and handling.
SHOCK ABSORBER: This is what controls spring movement. What is almost always used on our cars are mono-tube hydrolic shocks, so you don't need to know about anything else. A shock absorber's job is to absorb shock (duh!), which means that it dissipates spring energy. Hydrolic shocks do this by moving a small piston with orifices in it through a viscous oil, providing the energy damping needed to control spring movement. The size of the orifices determines the resistance to movement the shock will have, and adjustable shocks have adjustable sized orifices to offer a range of resistance to motion. Since a car's coil spring can be likened to a big slinky, you can imagine that the same way a slinky bounces off one step and jumps to another, where it compresses again and then jumps away once more. A spring will do this just the same, causing the suspension to compress & rebound over and over again after hitting a single bump. The primary job of the shock absorber is to prevent this cycle, and if it's properly matched to the spring's rate it will only allow this to happen once. This is what keeps the tire in good contact with the ground, so you can imagine the importance of getting the shock stiffness right for your springs. The secondary job of the shock is to add some resistance to motion in the suspension, much like the spring does. There's no need to get deep into that yet, just know the shock has an effect on both ride quality and performance.
ADJUSTABLE SHOCK ABSORBER: Adjustable shocks allow you to change their stiffness. Now that you know how important it is to match the shock settings to the spring in order to keep the tire in good contact with the ground, you can also understand how it's control over the spring movement will affect ride quality. Since the shock absorber has some level of control over how quickly the suspension can be compressed (because it adds additional resistance to the whole system), you can imagine that making the shock stiffer will have the same overall effect on ride quality as stiffening the spring. There are two main types of adjustable shocks: those that adjust stiffness of the compression stroke only and those that adjust stiffness on both compression and rebound strokes. It's not important to go over the different types of desgins here, but know that most shocks either only adjust compression stiffness (called single-adjustable shocks) or they adjust both compression & rebound at the same time (called double-adjustable shocks). This means that there is no way to adjust the bias between compression & rebound stiffness on double-adjustables, which is of principle design concern to shock manufacturers because it's so easy to get the bias wrong. There are indepently double-adjustable shocks which allow you to change this bias, but I wouldn't recommend them for the average enthusiast. You will probably just end up making the suspension damping worse than it was stock. Recommendations here are usually to get the double adjustable shocks that control both compression & rebound (but not independently), and that's probably the best idea for the average enthusiast.
COILOVER SUSPENSION: A coilover suspension is simply one that has the shock body located within the space inside the coil spring (as installed on the car). This is the best design possible because the shock is moving in the same plane as the spring, which ensures that it can most accurately control spring movement, plus it's usually the lightest. In our double wishbone suspension systems, the shock's only job is to control spring movement, so it makes sense that Honda equips all of their performance cars with coilover systems. The popular catch phrase "coilover" is only applied to systems that are sold complete with both shocks & springs (and sometimes upper mounts), but the truth is that every spring or shock you install on the car will function in a coilover system. Here's the basic breakdown as far as you are concerned: Honda uses almost exclusively the coilover setup on their current cars. Aftermarket spring manufacturers like Ground Control simply one-up their design by adding height adjustability to the system. This comes in the form of threaded shock bodies and adjustable spring perches, we generally refer to them as "sleeved springs". There are also shock manufacturers like Koni who one-up Honda in the shock absorber department by offering adjustable shocks, which are adjusted usually by a knob somewhere on the shock body or rod. Then at the top shelf of coilover designs, you have companies like Tein who one-up everybody else by offering a complete & ready to install coilover package that is adjustable in several different ways (height adjust, rebound adjust, compression adjust, whatever they throw in) and comes as a properly matched system. These are the systems we refer to as "true" or "complete" coilovers. Usually these shocks are rebuildable and offer custom valving options, and the company usually has a variety of spring rates available for you. If these are the best systems, it's simply because they are the most complete. The only system that offers a better garaunteed match between spring & shock are usually the stock units (which of course are not stiff enough and have no adjustability). What I am getting at here is that just because you get springs from one manufacturer and shocks from another does not mean that you won't have a kickass ride, it just means that there is more possiblity of mismatching one part to another. As we have pointed out many times, the simple Eibach Pro Kit & Koni adj. shocks combo seems to whoop ass on many other street setups without costing an arm and a leg (relatively speaking).
How do sway bars work, and how can you use them to tune your car’s suspension?
Most performance people know that stiffer rear sway bars reduce the understeering tendencies of a vehicle, but if you ask them exactly why this is they generally draw a blank. Usually they know the results, but not the reasons behind chassis tuning. This article is intended to answer those questions as well as give readers a better understanding of what goes on in your suspension when you take a corner. First, let's get an understanding of what lateral weight transfer is, because this will help you understand exactly how sway bars work to tune the balance of the chassis.
Lateral weight transfer is a function of three things:
- -overall weight of car
- -height of the Cg (center of gravity)
- -track width (this is the distance between the vertical centerlines of each tire on an axle, and many times track width is different on each axle)
So the first thing to notice here is that spring rate IS NOT a primary determinate in how much weight is transferred laterally on a car for a given amount of steering input. This is something many people have a hard time swallowing, but nevertheless it is true. All the springs primarily do is determine how much the suspension will compress or expand due to this weight transfer.
BODY ROLL, So why is body roll bad?
Two reasons:
Next, you need to know that the principle way you control body roll is through spring rates. And here's where we encounter the problem of not being able to change the static spring rates between cornering maneuvers and just going straight. To show a quick example of this:
- Say the amount of body roll during a corner is 10 degrees for a spring rate of 500 lbs. If you wanted to halve this amount of roll, you would need to roughly double the spring rate to accomplish it. Now we already know that limiting body roll can improve handling (depending on circumstances and suspension setup), but running a spring that stiff will cause the car to be so bouncy that the tire will rarely be in good contact with the ground, unless the road is perfectly smooth. So how can we selectively increase spring rates only under cornering so that our straight line stability & tire to road contact is not compromised by really stiff springs? The sway bar is the answer.
Now it should be stated here what sway bars essentially do, even though I know you may already know this. What a sway bar does is counteract the action of body roll during cornering by transferring spring rate from the inside wheel to the outside wheel in a corner. This means that you don't actually get any added spring rate; you just subtract it from one side and add it to the other. This has the ultimate effect of transferring load from the inside tire to the outside, which has the visual effect of compressing the suspension on the inside of the turn and expanding the suspension on the outside of the turn (thus limiting body roll). This is good mainly because it smoothes the speed of weight transfer during quick transitions and also limits the camber change experienced at the corners of the car through suspension travel. And of course, using this concept one can dial in the amount of total loading on the outside tire by varying the effectiveness of the sway bar (stiffer bars equal more transfer). And the beauty of all this is that it mostly only occurs during cornering, so our straight line spring rates are not affected. The other thing Ok, so hopefully now you all understand this concept. This is the most important part though, so if anything is still fuzzy read this again until you get it. Also, here's an example of how this works:
-For this example we will use a sway bar with a roll stiffness of 250 lbs.
Left front static load: 1000lbs
Right front static load: 1000lbs
-lateral weight transfer in a right hand turn
Left front: + 500lbs
Right front: - 500lbs
Total weight transfer: 1000lbs
-load transfer of sway bar(which is 250 lbs):
Left front: +250lbs
Right front: -250lbs
Total weight transfer: 1000lbs
-total effective cornering load for this example:
Left front: 1000 + 750= 1750lbs
Right front: 1000 - 750= 250lbs
-without sway bar
Left front: 1000 + 500= 1500lbs
Right front: 1000 - 500= 500lbs
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Alright, now we are coming into the home stretch of this learning curve. You need to know that although you cannot control the total amount of lateral weight transfer during cornering (as I stated earlier), you CAN have some control over how it is distributed on each axle. Looking at the above example, you see that with or without the sway bar involved, total weight transfer change is always 1000 lbs. You can't change this amount, but you can re-distribute it along the axle. And this is a function of spring rates entirely, which we now know is best controlled during cornering through the use of sway bars.
So how does one control the balance of a car when armed with this knowledge? It's actually very simple at this point, if you understand that increasing tire loading adds to the total amount of traction available from it, but this relationship is NOT linear. The more load on the tire, the more traction available, but the amount of traction gained diminishes as load increases. So at first it's almost a direct "you add 250lbs of load, you get 250lbs of extra traction", but at 1000lbs of load, you might only get 800lbs of extra traction. Knowing this, look at the example I gave of the sway bar at work. Since it transfers load away from the inside tire, you lose traction there. Although it transfers this load to the outside tire, it is already quite loaded and therefore the 250lbs of load will not increase overall traction by 250lbs. More like maybe 150lbs. Now the inside tire, being much less loaded, could have gained more like 220lbs or traction from the 250lbs of load. So look at what we have in the end: although the outside tires already do most of the work, adding a sway bar actually lowers the total amount of traction available at this end of the car by increasing the difference in load distribution. And the stiffer that sway bar is, the more it will limit the total traction available at that end.
So, to make a really long post short (again, sorry), what we end up with is the knowledge that weight transfer ultimately lowers the total amount of traction available at each end of the car. This is why the more we can limit total weight transfer (by increasing track, lowering the Cg height, or lowering overall vehicle weight) the more total traction will be available. But for the purposes of this post, we are explaining how sway bar sizing (which directly reflects it's roll stiffness amount) cures an unbalanced car. If a car is understeering, it's because the rear end has more total traction than the front. If you put a big sway bar on the rear suspension to limit the total amount of traction available there (by maximizing the amount of load transfer to the outside wheel), you can dial it in to match the front suspension's total available traction. And when we get really smart, we start to match the front & rear bars to one another to achieve the best balance through the largest possible range of suspension movement.
Nitrous 101
Can I run nitrous on my car?-
Nitrous can be run on pretty much any car, whether it be stock or a
fully built NA beast. If you have an older car or one with many miles
on it, you will want to run a compression check. The numbers for each
cylinder should be pretty close to each other and within Honda specs.
For example, if you had 240, 238, 242, and 245 on a JDM H22A then it
would be safe to run nitrous on that engine.
Secondly, aftermarket chips, ECUs, and Venom control modules that
advance the ignition timing are not safe to use with nitrous. You may
be able to use an MSD ignition timing controller or a Jacob's nitrous
mastermind to retard the timing only when you are spraying, but it is
very important to follow the rules for retarding your ignition timing
when you are spraying nitrous. I will discuss these rules later in
this post.Finally, nitrous loves high compression, but the nitrous
fuel ratio has to be tuned very precisely. 100 octane fuel will make
it much easier to run high compression and nitrous, but it can be done
to an extent on premium pump gas and good tuning.
Dry, Single fogger, and Direct Port: What's the difference?-
Dry Kits-Dry kits have a single nitrous nozzle plumbed into the intake tube (Mount the nozzle at least 6 in. from the TB) and they only spray
nitrous into the intake. The extra fuel is provided by the injectors,
when the ECU notices the extra oxygen molecules in the intake air
charge. Dry kits can only be jetted up to a 75 shot because the
nitrous is not distributed evenly to each cylinder. The injectors
give an even amount of fuel to each cylinder, but because some
cylinders are getting more than others you will get a dangerous lean
condition in that cylinder. Running lean leads to predetonation, and
predetonation is what blows motors.
Single Fogger Kits-
A single fogger kit has one fogger nozzle mounted on the intake tube
(Also 6in. from the TB). However, both fuel and nitrous are sprayed
through this nozzle. This kit has a fuel solenoid and a nitrous
solenoid, where the dry kit has just a nitrous solenoid. The idea
behind this kit, is that spraying fuel with the nitrous will fix the
lean condition that plagues dry kits that are jetted above a 75 shot.
The problem with this is that fuel is heavier than nitrous and
therefore it won't be able to make the turn to the first cylinder
after the TB as well as the nitrous does. Honda intake manifolds are
biased towards certain cylinders, which will still give uneven nitrous
and fuel distribution when usinf a single fogger kit. Some people swear
by these kits, but personally I'd rather plumb in a direct port kit for
anything higher than a 75 shot.
Direct Port Kits-
Direct port kits spray nitrous and fuel through single fogger nozzles
on each intake runner. This is the only kit that can provide perfectly
even nitrous and fuel distribution. This kit incorporates one nitrous
solenoid and one fuel solenoid, just like the Single Fogger Kit. The
only drawbacks to this kit is that it is hard to hide, and impossible
to hide from someone who knows alot about nitrous. Also when you want
to increase your shot, you have to change 8 jets as opposed to two on
the Single Fogger Kit. A direct port kit can be jetted to as low as a
75 shot and to high as your motor can hold (Providing your solenoids
can flow that much nitrous and fuel).
What do I need to run X shot?
First of all, you must always run premium fuel(91+ octane).
50 shot- All that you need is a set of one step colder copper NGK plugs or
a set of Zex plugs(Two steps colder than stock) and you can keep
the ignition timing at the stock timing.
60 shot- You need the colder plugs and you will want to retard your ignition
timing by a degree or two. You may want to look into getting an
aftermarket ignition and spark plug wires.
75 shot- Retard your ignition timing by 3 degrees, pick up an ignition, colder
plugs, spark plug wires, and look into getting a stronger clutch
because your stock one will be slipping very badly. If you find that
you are running lean or rich pick up a fuel pressure regulator. If you
are running a direct port kit, then you can pick up an Apexi VAFC to
control your fuel map.
100+ shot- While you can get away with running a 100 shot on a stock motor, I'm
not going to recommend it. If you plan on running any shot higher than
a 100 shot, you will need to beef up your bottom end. Forged pistons
and forged connecting rods are the first step. I have heard that it is
necessary to resleeve the block in order to run forged pistons on
H22As. Whether you believe this or not, is up to you. I figure that if
you are going to build a block, you may as well go all out and resleeve
it as well, but that's just me. Everything that you need for a 75 shot
you will also need for a 100+ shot. It will also be necesarry to
upgrade your fuel pump to a 225 lph pump. Walboro, NOS, and Holley are
all good choices for fuel pumps. A preogressive controller will also be
necessary to control the nitrous flow, so that you don't smoke the tires
for the first 1/8 mile. NOS, NX, TNT, and Jacob's Electronics all make
nice progressive controllers. 2 step colder plugs will help ward off
predetonation, and it will be necessary to retard the timing 2 degrees
for every 50 shot.
What brand should I get?-
NOS- NOS has been in the nitrous buisness for many years and has made a very
good name for themselves. They produce single fogger kits, direct port
kits, and dry kits. If you need a new solenoid, a nitrous line, nozzles
,distribution blocks, etc. NOS will make a replacement part.
NX- NX is very similar to NOS. It is a good company, that makes quality
parts, and they have been around for a while now.
Zex- Zex is the simplest dry kit that you can buy. The nitrous solenoid is
housed in a purlpe control module. This makes it an easier install,
but it also makes it so that you can't buy little individual parts to
fix your kit, such as solenoid plungers,springs, etc. like you can
with NOS and NX.
Venom- Venom is an expensive dry kit. It incorporates a computer program to
control the nitrous flow and it also uses a program to watch your AF
ratio, so that you don't run lean. The reason that I don't like Venom,
is that you can only jet a dry kit up to a 75 shot, so you you don't
put down enough power to have any really big traction issues. Basically
,the computerized nitrous flow controls are unnecessary. Secondly, a
fuel pressure safety switch from NOS and some dyno time will provide
just as much insurance that you won't run lean as the Venom kit, and
it will do it for cheaper.
Porting & Polishing 101
Airflow basics-
Getting good airflow through your cylinder head
is a must if you want to create big horsepower. How increasing airflow
gets you big numbers? First remember that your engine is basically a
big air pump. To get the most amount of horsepower out your head, you
need the max amount of fresh airflow into the engine and the most
amount of burnt exhaust out of the engine, with the least mechanical
effort. Extra intake and exhaust port restriction will create more
work for the motor, the extra created by restrictive ports is called
pumping loss. Look at is this way; if you suck a smoothie through a
coffee stir straw it will be very hard to get any of that smoothie
through that straw. If you switch to a larger straw you get a lot more
smoothie with less work—life is better with big straw right? The extra
work with the smaller straw, is the same as pumping loss. The more
work that the motor has to do to get the needed gases in and out of
the motor, means less hp for your wheels.
Volumetric Efficiency-
Another huge factor is volumetric efficiency.Volumetric efficiency is
the percentage of an engine’s displacement that is filled on each
intake stroke. Look at it this way: If you have a motor that displaces
1000cc. If the engine can take in 800cc or air on the intake stroke,
you motor has 80% volumetric efficiency. Your standard Honda motor has
about this amount of volumetric efficiency.How you get this number is
based on a motors port size and configuration to optimize volume and
geometry. This is good for a stock motor, but when you want modify
your motor for more power, your flow demands for that motor change as
well. Your basic bolt-on mods (header, intake,exhaust and cams, some
people don’t consider this a bolt-on but in my eyes they are) promote
higher rpm operation also demand more airflow. Although not a must to
get head work when your basic bolt-ons are on your motor, they do like
it more and will perform better with head work. That goes with just a
stock motor, but you get the idea. More flow usually requires bigger
ports and more cross-sectional area.The main effect of porting a head
is to reduce pumping losses and increasing volumetric efficiency by
reducing the restriction.
Porting-
In the porting process the intake and exhaust ports
are carefully reshaped (or should be if the porter really know what
he/she is doing) by hand. This reshaping consists of enlarging,
straightening, and streamlining to get rid of as much pumping-loss
inducing restriction, turbulence to increase the flow velocity of the
cylinder head as much as possible while make as much HP as possible.
Most of the time ports are straightened by a die grinder and a carbide
bit to a line of straight configuration. This straightening process
gets rid of any bends that may cause turbulence in the head. This doe
grinder that they use also is used to get rid of too cutting marks,
sand casting pits, and usual bumps and lumps that are made by the mass
production of our cylinder heads. Another process to gain more
volumetric efficiency out of the head is called, extrude honing. This
is where thick putty like goo full of abrasive is pushed through the
cylinder head, enlarging the ports, just like the natural flow of your
motor would like them to be. There are limits to porting though. You
can make ports to big. Symptoms of a head that has been ported to much
are a soggy bottom end, not making power. The other is a lumpy idle.
The type of porting for your car will depend on the type of set up you
want to run. Turbo cars like smaller port, high velocity ports without
a lot of overall port volume. Nitrous and supercharged cars like the
bigger ports with more overall port volume. The N/A street motors like
the smaller, high velocity ports, like the turbo cars. Drag N/A motors
will tend to like the bigger ports, this gets rid of the bottom end,
but they want top end so it really does not matter.
Valve jobs-
This is another major factor in getting the most out of your head.
Truly, a 50% of head flow gains can be found in the valve job. Stock
valve jobs are usually either one-angle valve job or two-angle valve
jobs. One-angle valve jobs, is just done on the seats surface,
two-angle valve jobs are a seat cut and a smooth throat cut. The high
performance valve jobs have three-angled cuts, one on each side of the
valve seat.1st- there is a throat cut typically around 60-70 degrees.
This will help the ease of the air’s transition to the 45-degree valve
seat cut.2nd- there is a 45-degree valve seat cut, which is literally
where the valve actually seats.3rd- this is called the top cut. This
cut is immediately after the seat cut and is typically 30-20 degrees.
This cut also helps to reduce valve shrouding of the airflow past the
valve (or before if we are talking about the exhaust valve) as the
valve starts to lift of the seat. There are five-angled valve jobs,
but I think for the most part they are not needed, that is why I
not going to get into the five-angle valve job process.
Combustion chambers-
Another thing that should be looked into if getting headwork done is
the quench zones of the head’s combustin chamber. The quench zone is
the flat are of the combustion chamber where the piston comes in close
proximity at TDC (top dead center). These quench zones promote more
complete burning and the chances of detonation.
Milling-
Milling takes of a thin layer of metal from the bottom of your head.
This creates a flat surface, which promotes a better seal to the block.
This also increases compression. Most head porter will slightly mill
the head, usually .050-.060. This increased the chances of piston to
valve contact. Remember though depending on how much you mill a head
will retard you timing anywhere from 4-6 degrees. To counter act this
you should get a set of adjustable cam gears. Which most have, who are
getting head work done. Since headwork is more saved to do when
building a motor up. Piston to valve contact can be catastrophic to a
motor. This can be done mathematically, but I highly suggest claying
the motor.It is important to maintain at least .045 on the intake
valves and .055 on the exhaust valves. You want .030 clearance
between any part of the piston and the cylinder head.
Looking to upgrade your Cam(s)?
There is Three things to look at when buying a cam(s)
(Duration, lift, and overlap).
I will explain below what you will wanna take in mind when purchasing the perfect cam for your application.
Duration-
Is the number of degrees of the crank rotation that the valve is held
open by a cam (don’t forget that the cam spins at half the speed that
the crank spins at). A general rule of thumb is that the more duration
the cam has, the more top-end power it will create, and this does
cause you to lose low-end power. The more duration the cam has the
more the valve will stay open during the cranks rotation. The longer
the valve stays open the longer the time the cylinder can be filled.
This is important at high rpm, since there is less and less time for
the cylinder to fill.
Lift-
Is the height that the valve is lifted of the valve seat. Usually the
more lift (with in reason) as the higher the valve is lifted the more
flow that can go by. Look at it this way, if you have your window open
half way you let in less air then if the window is open ¾ of the way.
The draw back to having more lift is that the valve opening and closing
speeds become high increasing the chance of valve float. This is why
you should upgrade to stiffer valve springs if the cams lift is
moderately aggressive.
Overlap-
Is the point at which both intake valves and exhaust valves are open
at the same time (at the end of the exhaust stroke and the beginning
of the intake stroke). Overlap is important, because having both
intake and exhaust valves open at the same time creates better
scavenging of stale exhaust to occur. This is because the flow from
the head into the cylinder (from the intake valves) creates a good
push to get rid of stale exhaust out of the cylinder. Just like
anything though, too much of a good thing is bad. If you get to much
overlap the flow from the intake valves will push gas out of the
cylinder before it has been used, thus wasting fuel, which equates to
power. One more draw back of to much overlap is reversion into the
intake ports. Reversion is when fuel/air is pushed back into the
intake ports. This reversion causes intake charge dilution at low rpm
as the backflow in the intake port gets in the way of cylinder filling.
Two things will occur because of this, cylinder pressure becomes poor
at low speeds because of the incomplete filling and the fuel/air
intake charge becomes diluted because of air rushing back into the
intake ports causes low speed misfire. This is why aggressive cams
that have big overlapping, create a ruff loopy idle. This misfiring
causes the motor to skip a beat in rhythmic fashion at idle and low
rpm. Usually firing once every four revolutions when the cylinder gets
enough fuel to touch off. This occurrence is called 8-storking,
because of the misfiring and the car skipping a beat it fires every
other stroke of the 4-stroke cycle.
Linear Mode
