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Truck Engine Performance Parts - Bolt-On Power Parts: Best of the Best 20

Posted in Features on October 1, 2003 Comment (0)
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Contributors: Joel Mollis
Photographers: Team OFF-ROAD

Even though your truck's engine likely sends adequate power to the wheels, more power is always a good thing. Fortunately, there are many methods of gaining more torque from a powerplant, some more obvious than others. Many of the best known involve increasing the airflow, enhancing the fuel flow, and easing the removal of exhaust gases. While the list of products that add extra engine power are easy to name, there are several you may not be aware of.

Fundamentally, making an engine perform more efficiently is the best way to improve throttle response and acceleration. This bolt-on power guide covers all the aspects involved with improving engine performance and efficiency in late-model trucks. The guide will provide an overview of what's involved in the installation of these parts, and it explains how the components typically enhance engine performance and power. Here are 20 of our favorite bolt-on performance goodies for your consideration.

1. Aftermarket Air Filters
It's likely that the OE air-filter element in your truck is made of paper, and you'll need to replace it within a year. Air filters made of paper are not the best material for filtration and will not provide efficient filtering action for very long. Vehicle manufacturers like paper filters because they're affordable and there are thousands of applications. An easy way to add power is by replacing a paper filter with a reusable (washable) filter. These filters have multiple-layer gauze elements with more pleats than the OE filter, meaning there is more surface area to improve airflow and filtering. These filters also have an extra layer of oil or synthetic material to filter out smaller particulates. Aftermarket gauze filters can be cleaned, re-oiled, and installed again and again, and they can improve fuel economy by 10 percent and provide as much as a 15hp increase depending on the truck.

2. Spark Plugs and Spark-Plug Wires
Performance spark-plug wires will make an ignition system perform to its full potential. Installing a new set of spark plugs and plug wires will deliver a slight increase in horsepower and torque and will make the engine run efficiently. By replacing OE plugs and wires with aftermarket plugs and wires, the ignition's spark will be stronger and more consistent, which will ensure the ignition of the fuel/air mixture during every ignition cycle. Also, high-quality spark plugs will remove heat from the combustion chamber while remaining resistant to heat. Some spark plugs have even been designed to create a larger spark. When it comes to spark-plug wires, a good set is built with the durability to resist wear from heat and will provide low resistance for the best possible electrical transfer from the coil and distributor to the spark plugs.

3. Air Induction
Improving airflow into an engine will almost always result in increased power. Air-induction kits, also known as air intakes, are designed to provide optimal airflow. Each system uses a main air tube that delivers reduced restriction to the flow of air, which increases the amount of air that can be brought into the engine's combustion chambers. With more air and a bit more fuel (automatically supplied by the fuel system's computer), more power is created. Air-tube kits use a two-pronged approach to increasing airflow: They smooth the path the air takes from filter to intake manifold and include a filter that provides additional surface area for the air to flow through. Another method used in some air-induction kits is the use of cold air. The theory behind cold-air intakes is that cold air is more dense with oxygen than warm air, meaning you can actually have more oxygen in a given amount of space if it's at a cooler temperature. When the engine's computer senses the increased air density or volume, it adds more fuel and spark advance, creating more power.

4. Throttle Body/Throttle-Body Spacer
Throttle bodies also work to bring air into the engine, and installing a larger throttle body will allow more air into the engine. Adding a throttle-body spacer to the mix doesn't increase airflow, but it allows the engine to make better use of the air that's being brought in. The Airaid throttle-body spacer shown here has a design that causes the incoming air to spin in a vortex pattern. The spinning action continues into the intake manifold's runners and on to the combustion chamber, which helps keep the fuel and air thoroughly mixed for an improved combustion process. Performance throttle bodies and plenum spacers can increase airflow by 15 percent or more, depending on the vehicle, and can improve power by 5 to 25 hp.

5. Exhaust System
On the exit side of the engine, the exhaust system is designed to rid the engine of spent exhaust gases. Aftermarket exhausts are made to provide the smoothest, most efficient route for the gases, with the fewest restrictions possible. Improving flow on the exhaust side means that the combustion stroke can be accomplished with enhanced efficiently. Once the exhaust gases are out of the way, there is space within the combustion chambers for fresh air and fuel. Additionally, OE mufflers are made to reduce sound and exhaust flow, and the components used to do this can cause a loss of performance. After-cat exhausts can improve performance by 10 hp or much more, depending on the system you choose.

6. Catalytic Converter
Removing exhaust gases from the engine is only part of what your truck's exhaust system does. Another role it plays is that of emissions reducer; the catalytic converter, in particular, exists to reduce the harmful emissions produced by the combustion process, which pollute the air. A catalytic converter cleans the exhaust by converting the toxins into relatively clean emissions. Over time, the converter can become clogged, and not only does it then function poorly, but the entire exhaust system's flow can be compromised as well. When a catalytic converter wears out, replacing it with an aftermarket catalytic converter can lower the exhaust emissions. Many aftermarket catalytic converters have a higher flow rate than stock, so the replacement can provide more power than in OE trim. Some states do not allow you to replace a catalytic converter until it is worn out or has significant mileage. As we would recommend with all of the modifications in this story, make sure installing these components on your 'wheeler is legal in your state.

7. Headers
When you bought your truck, it probably came with exhaust manifolds, two for V-configured engines and one for inline powerplants. These manifolds route exhaust gases from each cylinder but are not necessarily the most efficient parts for the job. Headers, which replace the stock exhaust manifolds, efficiently pull or scavenge the exhaust gases and draw in the next fuel charge. By doing this, headers reduce the pressure caused by gas buildup and make sure the air/fuel mix isn't polluted by the remains of the combustion process. Headers can increase horsepower by 35 and torque by 75 lb-ft and will improve fuel economy. There are several header styles to consider because different headers will improve an engine's power at different points within the rpm range.

8. Fuel Injectors
The fuel flow rate is an important part of improving the performance of every engine. Increasing the capability of the fuel system makes it easier to add more air and spark for more power. Aftermarket injectors do precisely that. If you add a component that increases the volume or pressure of air that enters the combustion chamber, aftermarket injectors ensure that the fuel side of the combination will provide the additional fuel that's needed for maximum power. Larger injectors are especially worthwhile if your truck is equiped with a supercharger or other high-performance modifications.

9. Fuel Pump
Installing a more efficient or higher-pressure fuel pump will typically increase the flow of fuel to an engine. Even though more flow can be advantageous, when choosing a new fuel pump it is important to select a model that provides the right flow rate for an engine's specific needs. A race-ready pump, while providing incredible fuel flow and pressure, would likely be too much pump for a mildly modified engine. A new fuel pump is almost a necessity after a supercharger is installed, and many supercharger systems include a new pump. There are two types of fuel pumps, in-tank and inline, that are either electric or mechanical in design. The inline pumps can be installed in more locations on the vehicle than the in-tank design but are farther from the source of fuel. Mechanical pumps are found mostly on older vehicles, and electric pumps are the common type for late-model trucks.

10. Engine Programmer/Chips
The theory behind modifying a truck's computer is that an aftermarket chip will customize the air/fuel ratio, ignition advance, and transmission shift points to fit your performance needs. For stock vehicles, a reprogrammed computer will optimize these functions, and for modified vehicles, it will change the ignition advance and shift points to best match the needs of the installed performance components. While you can purchase a programmer or chip and a thermostat separately, it is recommended that you install both at the same time, and some power packages come with a new thermostat. According to the manufacturers, these computer modifiers can increase engine production by as much as 25 hp.

11. Thermostat
Replacing an engine's OE thermostat with a lower-temperature model can reduce the overall temperature an engine runs at by causing the engine's fan to come on sooner than it does with the stock thermostat. This reduced engine temperature can cause the engine to operate more efficiently. The only people who should think twice about replacing their vehicle's thermostats with low-temperature units are those who live in cold climates, where engine and cooling-system heat are necessary to counter the cold weather. Choosing the right thermostat is not simply a matter of picking the lowest-temperature unit. Engines do like some heat, and if you choose a thermostat that causes the fan to come on at too low a temperature, it will start to have a detrimental effect on the overall cooling of the engine.

12. Ignition Upgrades
A new ignition system will help improve throttle response, power, and fuel economy and can smooth out the engine's idle. Aftermarket ignition systems, especially multiple-sparking units, provide a stronger, longer-duration multiple spark than standard ignition systems that emit one spark during the combustion cycle. The addition of a better spark means that more of the air/fuel mixture will be burned, delivering more power from the engine and reducing the amount of unburnt fuel that's sent out through the exhaust. A performance ignition system will simply make the engine operate more efficiently. There are many types of aftermarket ignitions that can make a difference on your truck; the trick is finding the right one for your application. There are ignition system components that are ideal for towing, off-road use, and heavy-duty applications, some specifically for supercharged engines and others for daily driving. Other methods you can use to improve the ignition system include replacing the distributor with a performance version and adding a powerful aftermarket ignition coil.

13. MAF Sensors
Mass airflow sensors (MAF) directly measure airflow into an engine via its sensing element. By measuring the airflow at the source, an MAF sensor knows exactly how much air is going into the engine, and it can quickly adjust the engine's computer to changes in airflow. As the MAF sensor notes changes in airflow, it sends a signal to ensure the proper amount of fuel and degree of spark are added to keep the combustion process correct. Because the air/fuel mixture is much more accurate with an MAF sensor and changes with the engine's operation, performance can be improved by 10 to 15 hp.

14. Intake Manifold
When you begin to look at making modifications to the key components of the engine to improve power, it's important to look at the entire range of engine mods for these improvements. For example, replacing the cam can make a difference in power, but the cam will create more horsepower and torque if it's teamed with a performance intake manifold. Just as replacing exhaust manifolds with headers means a more efficient method of moving gases, replacing an OE intake manifold with an aftermarket item means better airflow into the engine. Good aftermarket intake manifolds are application specific and are built to provide the best amount of air for that application. This is done by reducing restrictions and by making the design of the manifold deliver airflow in both quality and quantity.

15. Engine Accessory Drive Pulleys
There are many reasons why replacing an engine's accessory drive pulleys can improve power. If the new pulleys are made from durable materials, they will last longer than the originals, providing less belt slippage and improved contact with the serpentine belt. Smaller pulleys can increase engine cooling by speeding up both water flow and engine-fan speed. Using smaller pulleys can also mean a significant increase in power. Slowing the serpentine belt's speed by 25 percent will reduce the drag caused by the alternator and power-steering pump and increase engine power by as much as 8 to 10 hp.

16. Electric Fan
An electric fan is a more efficient design than the standard engine-pulley driven fan. Electric fans are made to work more precisely with the engine's needs, turning on and off whenever the cooling situation calls for it. While the engine fan is more necessary during idle and in heavy traffic, and less necessary on the open highway, an OE clutch fan is less capable of accurately working with changing driving circumstances. Electric fans can also pull in much more air than standard fans. This type of fan can increase horsepower and torque and can improve off-road vehicle performance.

17. High-Output Alternator
A high-output alternator will make an engine run better by providing enough electrical power to make the electrical system work properly. With many trucks, there are high-powered lights, entertainment features, and electronics goodies installed on-board to maximize function and enjoyment. Unfortunately, these devices can put a load on the OE charging system, and if the alternator is not a high-output model, it probably can't take the load. If you've sat at a red light and noticed that the headlights dimmed when you lowered the power windows, your OE alternator is not providing enough juice to the system. Adding extra batteries has been the common solution to the power problem, but the truth is that the alternator is the device that powers the electrical system and the battery. If the alternator can't handle the demand, power will be drawn from the battery, which may cause it to discharge. High-output alternators do a better job of powering accessories and recharging the battery, and they're built to withstand the heat created by a vehicle's engine.

18. Internal Engine Mods
When it gets right down to it, the most complex (and one of the most effective) ways to get more power out of an engine is by optimizing the engine's design. Replacing the cam or cylinder heads can make the engine dramatically more efficient and can draw more power from the air/fuel mixture. Four-stroke engines use exhaust and intake valves. The exhaust valves allow the removal of exhaust gases, making room for fresh air and fuel. The intake valves open to allow the next charge of air and fuel into the combustion chambers. When the camshaft rotates, it causes the valves to open and close, and the timing of this process can make the most out of the air/fuel mixture. Replacing the cam can mean improved high-rpm performance or better low-rpm performance, depending on the unit you choose. New cylinder heads can mean an increase in the amount of air coming into the engine, further increasing power.

19. Nitrous
Nitrous-oxide systems started out as a power booster for fighter planes but have since made the transition to performance-truck applications. Nitrous systems inject additional air into the combustion chambers, allowing additional fuel to be added, which makes for a stronger combustion cycle, generating additional power. N20 (don't ever, ever say, NOSS!) adds as much as 150 hp in an instant, but it is only meant to be used for a brief time. Nitrous is a power upgrade that can make driving onto a freeway on-ramp fun, but it isn't something that will give your truck long-term improved performance or efficiency. This is a modification that is safe when done properly, but it can be dangerous to an engine if the installation is improper.

20. Superchargers
The most noticeable modification you can do to give your truck more power is to install a supercharger. A supercharger can safely increase power by 75 to 100 hp, while dramatically improving torque. While there are several different supercharger designs, most push pressurized air into the combustion chambers, essentially putting a lot more air into the chambers. As blower technology advances, and more automakers become comfortable with the long-term reliability of superchargers, supercharges will become more available on OE applications. In fact, while some vehicles come from the factory with superchargers, there is a growing trend of making superchargers dealer-added items, which fall under the vehicle's original warranty. A supercharger installation is a worthwhile all-day process and not recommended for the novice do-it-yourselfer.


Fife, WA 98424
Paxton Superchargers
Oxnard, CA 93033
JBA Headers
San Diego, CA 92120
Holley Performance Products
Bowling Green, KY 42101
Advanced Engine ManagemenT (AEM)
Hawthorne, CA 90250
MAC Products
Temecula, CA 92590-3473
Dealers Sport Truck
Scottsdale, AZ 85260
Car Sound Exhaust
Rancho Santa Margarita, CA 92688
Dahlonega, GA 30533

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