Tech & Links

We begin with the piston all the way at the top with both valves closed. Just a few degrees ago the spark plug fired and the explosion and the expansion of the gasses is forcing the piston towards the bottom of the cylinder. This is the event that actually pushes the crankshaft around to create the power and is referred to as the “power stroke” (figure 1). Each “stroke” lasts one half crankshaft revolution or 180 crankshaft degrees. Since the camshaft turns at half of the speed of the crank, the power stroke only sees one fourth of a turn of the cam, or 90 camshaft degrees.

As we move closer to the bottom of the cylinder, a little before the piston reaches the bottom, the exhaust valve begins to open. By this time most of the charge has been burned and the cylinder pressure will begin to push this burnt mixture out into the exhaust port. After the piston passes the true bottom or Bottom Dead Center, it begins to rise back to the top. Now we have begun the exhaust stroke, another 180° in the cycle (figure 2). This forces the remainder of the mixture out of the chamber to make room for a fresh, clean charge of air-fuel mixture. While the piston is moving toward the top of the cylinder, the exhaust valve quickly opens, goes through maximum lift and begins to close.

Now something quite unique begins to take place. Just before the piston reaches the top, the intake valve begins to open and the exhaust valve is not yet fully closed. This doesn’t sound right, does it? Let’s try to figure out what is happening.

The exhaust stroke of the piston has pushed out just about all of the spent charge and as the piston approaches the top and the intake valve begins to open slowly, there begins a siphon or “scavenge” effect in the chamber. The rush of the gases out into the exhaust port will draw in the start of the intake charge. This is how the engine flushes out all of the used charge. Even some of the new gases escape into the exhaust. Once the piston passes through Top Dead Center and starts back down, the intake charge is being pulled in quickly so the exhaust valve must close at precisely the right point after the top to keep any burnt gas from reentering. This area around Top Dead Center with both valves open is referred to as “overlap”. This is one of the most critical moments in the running cycle, and all points must be positioned correctly with the Top Dead Center of the piston. We’ll look at this much more closely later.

We have now passed through overlap. The exhaust valve has closed just after the piston started down and the intake valve is opening very quickly. This is called the intake stroke (figure 3), where the engine “breathes” and fills itself with another charge of fresh air/fuel mixture. The intake valve reaches its maximum lift at some defined point (usually about 106 degrees) after top dead center. This is called the intake centerline, which refers to where the cam has been installed in the engine in relation to the crankshaft. This is commonly called “degreeing”. We will talk about this later also.

The piston again goes all the way to the bottom and as it starts up, the intake valve is rushing towards the seat. The closing point of the intake valve will determine where the cylinder actually begins to build pressure, as we are now into the compression stroke (figure 4). When the mixture has all been taken in and the valves are both closed, the piston begins to compress the mixture. This is where the engine can really build some power. Then, just prior to the top, the spark plug fires and we are ready to start all over again.

The engine cycle we have just observed is typical of all four- stroke engines. There are several things we have not discussed, such as lift, duration, opening and closing points, overlap, intake centerline and lobe separation angle. If you will refer to the valve timing diagram when we discuss these terms it might make things a lot easier to understand.

Most cams are rated by duration at some defined lift point. As slow as the valve opens and closes at the very beginning and end of its cycle, it would be impossible to find exactly where it begins to move. In the case illustrated, the rated duration is at .006″ tappet lift. In our plot, we use valve lift so we must multiply by the rocker arm ratio to find this lift. For example: .006″ x 1.5 =.009″. Instead of the original .006″ tappet lift, we now use .009″ valve lift. These opening and closing points are circled so that you can see them. If you count the number of degrees between these points you will arrive at the advertised duration, in this case 270 degrees of crank- shaft rotation. In this illustration this is the same for both the intake and the exhaust lobes, thus making this a single pattern cam. Some cam manufacturers rate their cams at .050″ lift. If we again multiply this by the rocker arm ratio, we get .075″. We can mark the diagram and read the duration at .050″ lift. This cam shows around 224 degrees, standard for this 270H cam. The lift is very simple to determine. You can simply read it from the axis going up. This is the lift at the valve as we said earlier. Sometimes you will hear lift referred to as “lobe lift”. This means the lift at the lobe or the valve lift divided by the rocker arm ratio. In this case, it would be .470″ divided by 1.5 or .313″ lobe lift. The lift is simply a straightforward measurement of the rise of the valve or lifter.

We touched on opening and closing points a little earlier, but now we want to consider them even further. We talked about when these points occur, and how they are measured. As you can see in figure 1, the valve begins to move very slowly then picks up speed as it approaches the top. It does the same closing, coming down quickly then slowing to a gentle stop. It’s kind of like driving your car. If you were to go from 0 to 60 mph in a fraction of a second and stop instantly, you can imagine what that would do to the car, not to mention the driver. It would be much too severe for any valve train to endure. You would bend pushrods, wear out cams, break springs and rockers, and lose all dynamic design. The cam would not run to the desired RPM level as you would have all these parts running into each other. As the valve approaches the seat, you also have to slow it down to keep the valve train from making any loud noises. If you slam the valve down onto the seat, you can expect some severe noise and a lot of worn and broken parts. So it is easy to see that you can only accelerate the valve a certain amount before you get into trouble. This is some- thing COMP Cams® has learned over the years-how far you can safely push this point.

Looking a bit further at the timing points, the first one we see on the diagram is the exhaust opening point. We have all noticed the different sounds of performance cams, with the distinct lopes or rough idle. This occurs when the exhaust valve opens earlier and lets the sound of combustion go out into the exhaust pipes. It may actually still be burning a little when it passes out of the engine, so this can be a very pronounced sound.

The next point on the graph is the intake opening. This begins the overlap phase, which is very critical to vacuum, throttle response, emissions and especially, gas mileage. The amount of overlap, or the area between the intake opening and the exhaust closing, and where it occurs, is one of the most critical points in the engine cycle. If the intake valve opens too early, it will push the new charge into the intake manifold. If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. If the exhaust valve closes too early it will trap some of the spent gases in the combustion chamber, and if it closes too late it will over-scavenge the chamber; taking out too much of the charge, again creating an artificially lean condition. If the overlap phase occurs too early, it will create an overly rich condition in the exhaust port, severely hurting the gas mileage. So, as you can see, everything about overlap is critical to the performance of the engine.

The last point in the cycle is the intake closing. This occurs slightly after Bottom Dead Center, and the quicker it closes, the more cylinder pressure the engine will develop. You have to be very careful, however, to make sure that you hold the valve open long enough to properly fill the chamber, but close it soon enough to yield maxi mum cylinder pressure. This is a very tricky point in the cycle of the camshaft.

The last thing we will discuss is the difference between intake centerline and lobe separation angle. These two terms are often confused. Even though they have very similar names, they are very different and control different events in the engine. Lobe separation angle is simply what it says. It is the number of degrees separating the peak lift point of the exhaust lobe and the peak point of the intake lobe. This is sometimes referred to as the “lobe center” of the cam, but we prefer to call it the lobe separation angle. This can only be changed when the cam is ground. It makes no difference how you degree the cam in the engine, the lobe separation angle is ground into the cam. The intake centerline, on the other hand, is the position of the centerline, or peak lift point, of the intake lobe in relation to top dead center of the piston. This can be changed by “degreeing” the cam into the engine. Figure 1 shows a normal 270 degree cam. It has a lobe separation of 110°. We show it installed in the engine 4° advanced, or at 106° intake centerline. The light grey curves show the same camshaft installed an additional four degrees advanced, or at 102 degrees intake centerline. You can see how much earlier overlap is taking place and how the intake valve is open a great deal before the piston starts down. This is usually considered as a way to increase bottom end power, but as you can see there is much of the charge pushed out the exhaust, making a less efficient engine. There is a recommended intake centerline installation point on each cam card, and it is important to install the cam at this point. As far as the mechanics of cam degreeing, COMP Cams® has produced a simple, comprehensive video (part #190) that will take you step-by-step through the process.

On these pages we have discussed theory but the video will show you how to actually get the job done. COMP Cams® has put a great deal of effort into the design and engineering of our camshafts. All of these points were considered in each and every cam listed in this catalog. What we intend to do here is show that camshaft design is not some “black art”, but rather a series of decisions and compromises based on the exact application of the cam. Only our many years of experience can say whether a certain combination of lobes will work, so you should trust the judgement of those who have engineered these combinations.

The following tables illustrate how variations in lobe separation angle and cam timing will effect the behavior of the engine in which the camshaft is installed.

EFFECTS OF ALTERING CAMSHAFT TIMING

EFFECTS OF CHANGING LOBE SEPERATION ANGLE (LSA)

CAMSHAFT GEOGRAPHY AND LOBE FUNCTION

1) Max Lift or Nose
2) Flank
3) Opening Clearance Ramp
4) Closing Clearance Ramp
5) Base Circle
6) Exhaust Opening Timing Figure
7) Exhaust Closing Timing Figure
8) Intake Opening Timing Figure
9) Intake Closing Timing Figure
10) Intake to Exhaust Lobe Separation

Effects Of Changes In Cam Timing And Lobe Separation Angle

The following tables illustrate how variations in lobe separation angle and cam timing will effect the behaviour of the engine in which the camshaft is installed.

EFFECTS OF ALTERING CAMSHAFT TIMING

EFFECTS OF CHANGING LOBE SEPARATION ANGLE (LSA)

CAMSHAFT GEOGRAPHY AND LOBE FUNCTION

1) Max Lift or Nose
2) Flank
3) Opening Clearance Ramp
4) Closing Clearance Ramp
5) Base Circle
6) Exhaust Opening Timing Figure
7) Exhaust Closing Timing Figure
8) Intake Opening Timing Figure
9) Intake Closing Timing Figure
10) Intake to Exhaust Lobe Separation

Today’s engine oils are not the same as they were even a few years ago.

Phosphorus and Zinc Reduction

• Phosphorus degrades catalytic converters
• Zinc & Phosphorus content unlimited before 1993
• Phosphorus now limited to max 800 ppm (API SM / ILSAC GF-4)
• Mandated for 10W-30 and lower – still occurring in higher grades
• Diesel oils now limited to 1,200 ppm Phosphorus (Oct. 2006)

Increased Detergents

• Exhaust Gas Recirculation Valves
• Increased drain intervals – less waste oil

Lower Sulfur

• Restricted Sulfur content

ZINC VS. DETERGENT

Detergent and dispersant additives “compete” against zinc in the engine because they are polar molecules as well. Detergents and dispersants clean the engine, but they don’t distinguish between sludge, varnish and zinc – they clean all three away.

Modern API certified oils contain higher levels of detergents and dispersants due to the exhaust gas recirculation (EGR) systems on passenger cars and diesel trucks. The “old school” theory on engine break-in was to run non-detergent oils, and this allowed for greater activation of the zinc additive in the oil.

Joe Gibbs Driven BR Break-In oils utilize the correct balance of anti-wear additives and detergents, so you don’t need to buy expensive additives to try to “fix” a low zinc (ZDDP) oil.

HOW DOES IT WORK?

ZDP (aka Zinc) and Moly (MoS2) are polar molecules, so they are attracted to carbon steel surfaces where they react with heat, to create a sacrificial additive coating. The protective coating prevents metal to metal contact, which reduces friction and wear. Moly can withstand pressure up to 500,000 psi.

Detergent additives are also polar, so they “compete” against the Zinc and Moly.

Key Protection For:
Cams, Lifters, Push Rods, Wrist Pins, Distributor Gears, Bearings, Etc…

WHY IS ZINC IMPORTANT?

As Load Increases, Lubrication Moves From Full Film (Hydrodynamic) To Boundary Lubrication. Zinc Provides Boundary Lubrication.

PROPER LUBRICATION

The Right Oil

• Proper viscosity and additives for operating temperature, RPM and load
• There is no “magic molecule” that prevents engine failures
• No amount of Zinc can fix bad geometry – lifters must spin

In The Right Place

• The best oil sitting in the oil pan doesn’t help your camshaft
• Oiling system design is critical to proper lubrication
• Look into EDM hole lifters, piston oilers, valve spring oilers

In The Right Time

• On time delivery is critical
• Cold starts and Dry starts account for majority of engine wear – Multigrade oils dramatically reduce cold start wear

In The Right Amount

• Proper oil flow is critical at all times
• Oil is the lifeblood of an engine

WHAT IS OIL?

A quart of oil contains 2 things:

Base Oil

Roughly 85% of what is in the bottle is base oil. Most base oils come from crude oil. There are 5 different classes of base oil based on purity and source material.

• Crude
• Distillation Gases
• Vegetable oils and Animal fats

Additive Package

Roughly 15% of an oil is the additive package, but that 15% plays a
big role in performance.

• Detergents
• Anti-Wear (Zinc)
• Friction Modifiers (Moly)
• Viscosity Modifiers

WHERE DOES OIL COME FROM?

Crude oil is fractioned by distillation into different “cuts” of oil and fuels. Engine oils come from the middle part of the tower, and are then refined by various methods to become base oil. The fraction of oil that becomes engine oil contains 3 families of molecules – Paraffins, Naphthas, and Aromatics.

Paraffins: Good VI, preferred molecule
Naphthas: Low VI
Aromatics: Very Volatile

Base Oil Choices

• Group I, II & III are mineral oils (Crude Oil)
• Group IV – PAO Synthetic (Distillation Gases)
• Group V is everything else   (Animal fats and Vegetable oils)

SYNTHETIC VS. MINERAL

The difference between synthetic and mineral oils are the structure of the molecules and the purity of the oil. Refined crude oil contains complex mixtures of different molecular structures and saturates (Nitrogen, Sulfur and Oxygen). There is no way to select only the best materials from this mixture. Thus mineral oils contain both the most suited materials and the least suited materials for an engine oil. Synthetic oils are man made, and have tailored molecular structures with predictable properties. Because of this, synthetics can have the best properties of a mineral oil without the un-desired materials. Synthetic oils have two unique advantages over mineral oils – lower traction coefficients and higher oxidation stability. This translates into improved energy efficiency – less friction – and longer drain intervals.

APPLICATION SPECIFIC

Oil is Not One Size Fits All

To achieve maximum lubricant performance, an oil must be formulated to meet the specific need of the application.

The choice of oil for any application should be guided by the following operating conditions:

• Speed
• Load
• Temperature
• Service Interval
• Equipment Design
• Operating Environment

STREET OIL VS. RACING OIL

Modern Engine Set-Ups

• Low RPM (Low Load – Less Need For Anti-        Wear)
• Overhead cams (No Flat Tappets or Push Rods – Less Need For Anti-Wear)
• EGR Valves (More need for Detergents)
• Extended Drain Intervals (increased detergents & acid neutralizers)
• Modern engines built to use modern oils in order to achieve cleaner emissions

Race Engine Set-Ups

• High RPM (High Load – More Need For Friction Modifiers)
• Flat Tappet cams and Push-Rods – More Need For Anti-Wear
• Short Drain Intervals and EGR valves – Needs Fewer Detergents

ADDITIVE CLASH

Additive clash occurs when two different additive chemistries interact antagonistically resulting in dips in protection. The high levels of detergent in API oils can contribute to Additive Clash.

Typical Break-In Procedure:

Three different lubricant chemistries working against each other.

Joe Gibbs Driven System Approach:

Matched lubricant chemistries working together to provide sustained protection.

Establishing an effective anti-wear / EP film in an engine is not unlike painting your car. Think of this system ofassembly grease followed by break-in oil and then synthetic oil like the primer, sealer and base color of automotive paint. It makes a difference when you apply the right products for the job in the correct order!

WHAT IS VISCOSITY?

Viscosity is a measure of flow. Oil viscosity is generally thought of in terms of SAE grades, like 15W-50.

• An oil’s flow rate increases as temperature increases.
• SAE grades are ranges, not an exact measurement of an oil’s flow rate.
• The number before the W is measured at -22F. The Number after the W is measured at 212F.
• Kinematic Viscosity measures the exact flow rate of an oil at both 100F and 212F degrees.

SAE GRADES
SAE grades are only measured at 212F. The number before the “W” in a 15W-50 or 0W-30 is a cold cranking index that is measured at -22F.

OIL CLEARANCES

Wider Bearing Clearances Require Higher Viscosity Oil To Maintain Hydrodynamic Oil Wedge

OPERATING VISCOSITY

The “Operating” viscosity is the Centistoke flow rate of an oil at the operating oil temperature of an engine. Some engines run low oil temperatures, and other engines run extremely high temperatures. Low viscosity oils work well in low temp applications, and high viscosity oils work well in high temp applications. The SAE Grade viscosity of these oils are very different, but the operating flow rates are very similar.

VISCOSITY MODIFIERS

– Polymer based oil additive – makes multi-grade oils possible
– “Shrink” under shear forces
– Shear forces in race engines are greater than in production engines
– Prone to permanent shear loss under extreme pressures
– Adds friction modifying and dispersant functions

Installing a carburetor is one of the more basic race car procedures so we won’t go into detail on it. However, there are a few crucial items needing special attention. A carburetor is designed to precisely meter fuel and air; if the sealing surface is damaged or obstructed the carburetor will essentially have an uncontrolled source of air – the dreaded vacuum leak! A common mistake that can also lead to trouble is over tightening. Moving in a crisscross pattern will evenly distribute the torque of your wrench and ensure that the mounting flange of the carburetor is not damaged. Once the carburetor is properly mounted, take a few moments to move the throttle linkage. For your own safety it is imperative that the throttle returns to the closed position on its own and moves freely.

After the carburetor is mounted on the engine and everything else works properly the initial tune- up can be dialed in. Float level is very important to the overall performance and consistency of your race car; there are ill-side affects if you deviate from this a crucial step. Once you have filled the fuel bowls and primed the engine, start it up. Set the float levels while the engine is running at idle. Normally, a Quick Fuel Technology carburetor will have the fuel level half-way up the sight window with 6.5-7 PSI of fuel pressure. Other brands and some older carburetors will require a sight plug removed to check this. Take precaution make sure that you keep fuel away from any ignition source. The next step will be to set the idle mixture. Most carburetors have an adjustable idle feature whether it is 2 screws or 4. Four barrel race carburetors typically have 4 screws, one for each barrel. The ideal method for setting idle mixture is with a manifold vacuum gauge. Setting the screws to attain the highest reading of vacuum is the standard method but not every engine and combination will follow that setting. Some modern race engines require more fuel at idle. Too lean of a mixture could cause the engine to die once you click it into gear. Idle mixture is a part of the process you will simply have to play with to determine what you prefer, take it slow and go a half turn at a time. Always remember that not all 4 screws need to be turned the same amount out or in.

Once you have set the float level and idle mixture; the last step is adjusting your idle speed. Many carburetors have a transfer slot that aids the carburetor in its transition to wide open. If the throttle plate position is too far up (and into the transition slot) your idle quality will be low and the car might stumble at the starting line. The plate position can be corrected by adjusting your mixture screws (again something you will have to experiment with). The goal of a proper idle speed and mixture is to have the engine have a suitable idle while in neutral or in gear. The main idea is to have an idle that makes the car smooth and predictable.

A properly set-up carburetor will give a solid baseline for fine tuning to achieve maximum performance. If the carburetor is not dialed in correctly when first installed it has the potential to compound other problems and potentially cost more money (and time) to fix.

Carb Class: Air Bleed Basics

You’ve heard of them, but what do they do? Air bleeds, sometimes referred to as “air jets” or “air bleeders” play a vital role in the operation of your carburetor. Air bleeds are responsible for determining the amount of air that will mix with each circuit in the metering block. Virtually every carburetor you come across will have these which make this a universal discussion. The amount of air bleeds a carburetor will have is dependent on the number of throttle bores and circuits the carburetor has. In the context of racing carburetors, it helps to think of them as (4) one barrels. Most racing carburetors will have either 8 or 12 air bleeds depending on whether they are 2 or 3 circuit. Each barrel will have one bleed per circuit.

Idle Air Bleed: The idle air bleed could be the hardest working one of them all. Air to be mixed with idle fuel is provided by the idle air bleed. The idle mixture screws rely on air provided by this bleed. Often racers have complained of poor idle quality and no response to adjustment of their mixture screws, this is due an incorrect idle bleed. Many idle issues can be addressed by simply adding or taking away air.

Intermediate Bleed: The intermediate bleed is found on 3 circuit carburetors ONLY. The intermediate bleed provides air for the 3rd circuit. The intermediate circuit is only adjustable externally by the air bleed and to tune it otherwise would require you to take the fuel bowl and metering block off of the carburetor. On most large flange carburetors this would be the bleed found in the middle.

High Speed Bleed: The high speed air bleed or also referred to as the “main bleed” correlates to the main system. The high speed air bleed controls how much air is fed to the emulsion channels of the metering block. To explain further, the emulsion channels distribute that air further to different parts of the main well where it mixes with fuel and ultimately goes to the booster. The high speed air bleed is generally located closest to the squirter when looking at most race carburetors.

Now that we know what each air bleed does, how do we tune them? Tuning with air bleeds is often easier than anything else on a carburetor. Most modern race-style carburetors have screw-in air bleeds that can be exchanged externally with a simple hand tool. Gone are the days of pin drills and dial calipers. Air bleeds often resemble a main jet only slightly smaller. Tuning is simple in that you just need to remember the size of the hole determines how much air is coming into the carburetor. If you want to richen up the idle simply replace your idle air bleed with a smaller one (less air in the system = more fuel = richer idle), this will help you get your mixtures screws within the 1-2 turn range. What if you want to lean out the intermediate so you can get your car to come off of the transbrake a little cleaner? Increasing the size of the intermediate bleed will lean out that circuit. Just remember that too much of a good thing can get you into trouble – before fine tuning a carburetor you should take note of the stock specs so you can always come back to where you started.

Carb Class: Fuel Bowl Basics

In past issues we have discussed that horsepower can be found in the individual components of carburetors – one often neglected component that is integral to the performance of your race car is the fuel bowl. While no one component is more important than another, the fuel bowl is integral to the performance of your engine and the way your race car goes down the track. All carburetors (no matter the size or brand) will have some type of system that controls fuel delivery to the carburetor. For the purposes of this article we will assume that most people use the same style of carburetor and have a removable “modular” style fuel bowl. Fuel bowls, for those that might not know, are the pieces of the carburetor that you would have to drain and remove to change the jets of your carburetor. If a fuel bowl is incorrect for the application or built with improper components the performance of your race car will ultimately suffer.

Fuel bowls come in different shapes, sizes, materials, and even colors. The choices a racer has when it comes to a carburetor can be overwhelming but with a little research and some good communication racers can ensure they will be satisfied with the combination and hopefully go some rounds. The first question you should consider when discussing fuel bowls is what type of fuel does your car use? E85, E98, race gas, and methanol all have a different BTU output and require varied amounts of flow to make best horsepower – ultimately you must determine if the fuel bowls can support the flow your engine requires. Another issue to be aware of is that certain fuels are corrosive, with that said, fuel bowls should be outfitted with components to resist any damage; if there is corrosion then one can assume there will be some particulate matter getting into the fuel system which will cause issues elsewhere in the carburetor. One of the last things we usually consider when outfitting a carburetor is the footprint of the carburetor (is there enough space between other components or another carburetor that you need to account for when choosing the size or type of fuel bowl?). With this information laid out one can now see that there is some considerable importance in the selection of a proper fuel bowl.

Modern race carburetor fuel bowls come in two basic configurations each with their own type of float. The first we will go over is the side hung bowl – named due to the nature of the way the float is situated inside the bowl itself. This type of fuel bowl is generally used in situations where a 2×4 set of carburetors must be mounted inline or on certain class carburetors where the rules require its use due to it being factory equipped. The side-hung bowl is compact, and because of that characteristic, has some limitations. One major drawback of side-hung bowls is that they do not offer much float drop – this compromises fuel flow by not allowing the needle to fully open. Another drawback to the use of the side-hung bowl is the float design itself. The float design of a side-hung float does not produce a high amount of leverage and therefore it cannot withstand much fuel pressure (the float has difficulty overcoming the fuel flow and shutting the needle). The other main configuration of fuel bowl is the center-hung style. Center-hung bowls are generally dual inlet (or dual feed) and unlike their side-hung brethren, you can opt to plumb them from either side. Named for the way the float is mounted within the bowl, a center-hung float offers more drop, flow, and leverage. A center-hung bowl is physically larger than a side-hung bowl and will have more capacity (something required on methanol and E85/98 race cars) which decreases the chance of running out of fuel and going lean down the track. Widely adapted and seen on the majority of carbureted race cars in the pits, the center-hung fuel bowl was the one of these two mentioned fuel bowls that was designed with performance in mind.

The last thing to consider when reviewing your fuel bowl setup are the specific components inside the fuel bowl. There are several brands and types out there for each little component so finding a quality piece is never an issue. Diaphragms, floats, and needle valves come in all shapes and sizes in a wide variety of materials to suit your application and should be selected with the help of a specialist. The right combination of components are what add up to a winning race car and your carburetor components play an integral part.