How to Increase Horsepower on Cars

by Contributing Writer; Updated June 12, 2017

Introduced in 1987, the Detroit Diesel Series 60 does well in fuel-economy tests and is considered as one of the most cost-effective vehicles of its kind. It rates consistently at the top of its category. The six-cylinder engine already produces 425 horsepower but a few simple modifications can increase that even further.

Under The Hood:

 How to Increase Horsepower on a Detroit Diesel Series 60

Upgrade to the latest version of the Detroit Diesel Electronic Control System. The DDEC (IV) not only allows owners to run diagnostics on the engine, it also permits the changing of the horsepower settings. Go to your local dealer to have them download the current software to your engine's computer.

Replace the factory air filter with a performance version to allow more air to flow through the engine. Change the air filter anyway every few thousand miles as a filter that is clogged will decrease your horsepower. You will know it needs changing when it loses the white color it starts with and becomes dull.

Install a high flow muffler to allow air to flow out of the engine freely. A ported exhaust manifold can increase the horsepower that your engine achieves by up to 35 percent.

Invest in performance fluids for your engine. Replace the standard coolant and engine oil with ones designed to increase the efficiency of your engine.

 How to Increase Horsepower on a Mercury Outboard Motor

Perform a full service tune on the engine. This will help the engine last longer and increase its efficiency. Change the fuel, check the oil and other levels. Clean the engine and perform a thorough maintenance on the engine. This will ensure the engine is in the best condition possible. A seldom serviced engine will not perform as well as a frequently serviced one.

Use fuel additives. Fuel additives are chemical mixtures designed to help increase performance and efficiency. There are many additives to chose from; some are designed for small engines others for larger ones. The right additive is the one designed for your engine. They are generally inexpensive (less than $20) and last a long time. Often only a small amount is added to a full fuel tank.

Increase performance through airflow intake. The engine sucks in air and blows air out. If this process is hindered, then performance is lost. Examine the air intake on the engine. Look for obstructions, debris or other dirt that may clog the engine. Clean the air intake thoroughly. Examine the air filter and replace if it is dirty or damaged.

Increase performance through airflow exhaust. If the exhaust (air leaving the engine) is restricted, it can cause pressure to build up and reduce the efficiency of the engine and its power. Replacing the exhaust unit with an after-market system can help increase performance.

 How to Increase the Horsepower in a Chevy Tahoe

Replace the exhaust. Whether it’s a V8- or a V6-powered Tahoe, the stock exhaust system is fairly restrictive thanks to its small diameter. A larger diameter exhaust and performance muffler will allow the motor to run more efficiently and produce more horsepower. An exhaust system should be installed by a muffler shop since it takes special cutting and welding tools and a lift to make the job easier.

Install tubular headers. The manifolds on a V6 or V8 Tahoe are the components that are bolted to the head and route spent exhaust gases from the engine to the exhaust. Stock manifolds are cast, which results in smaller than optimal passages and a rough surface, both of which slow the flow of exhaust gases. Tubular headers are bolted to the engine in place of the stock manifolds and feature smooth surfaces and bends and a larger internal diameter, all of which are good for power.

Install a cold air intake. Though the Tahoe is a sport utility vehicle, there are several companies that make and sell a cold air intake to replace the stock air box. The air box restricts optimal airflow to the motor because of its design. A cold air intake consists of larger diameter tubing and a larger air filter that delivers additional cold, dense air to the Tahoe’s motor. To install this, simply disconnect the stock air box from the engine and remove the air box from the engine bay. The new cold air intake installs in its place.

Install a high performance chip in the computer. This will reprogram the engine’s computer so that it receives more fuel, spark and air as well as change the timing to a more aggressive setting intended to increase performance.

Items you will need

  • Socket set and ratchet

  • Specialty automotive tools

 How to Increase the Horsepower on a 1979 Corvette Engine

Increasing the horsepower of a 1979 Chevrolet Corvette

Change out the spark plugs with hotter, high-performance types by turning the plug counterclockwise and replacing it. Spark plugs are rated by their heat range, which is the minimum operating temperature. Hotter or colder plugs will increase performance or economy, and many multi-node plugs will not need to be gapped like normal styles.

Replace the ignition wires with thicker cored wires, which will increase horsepower by sending more energy to the plug. Stock wires are 6 or 7 mm thick, and over time they can crack or split, reducing the effective energy that reaches the plug. Pull the wire free from the distributor and spark plug, then press the new wire firmly into place. Some types of performance wires will require some assembly, so check the instructions included with the set.

Replace the motor oil, transmission oil and differential oil with an all-synthetic brand. The standard oil of 1979 was organic, and as long as the seals do not leak, switching to synthetic can gain as much as 20 horsepower on a Chevy 350 motor. The engine and transmission will require filter replacement, but the differential will not.

Clean the carburetor and throttle plate with a spray cleaner by opening the air intake, then saturating the interior of the carburetor with the engine off. Some types of cleaners can be used while the motor is running and sprayed in spurts so that the engine doesn't bog down. Many years of debris and carbon can build up on all four barrels of a 1979 carburetor system, so removing it from the motor and spraying it completely is an option.

Replace the air intake with an open-element style filter. This is usually done by unscrewing the top intake plate, unscrewing the snorkel connector, then mounting an open element filter plate directly over the carburetor with the existing screw. Emissions equipment won't connect to the open element filter, but the horsepower gains can be enormous.

Items you will need

  • Socket set

  • Wrench set

  • Screwdrivers

  • Carburetor cleaner

  • Synthetic motor oil

  • High-performance spark plugs

  • 8 mm ignition wires

 How to Increase Horsepower on a Ford F-150 4.6 Engine

Tune up your truck. Follow the directions in your owner manual to complete the tune up according to the manufacturer's specifications. A tune up includes changing the spark plugs and wires, changing the oil and replacing the air filter. You need to replace the oxygen sensor as well if it has not been changed in the last 75,000 miles.

Replace the factory air-intake box with a high-performance system. Since the high-performance mechanism is less restrictive, the increase in air flow will boost the engine's horsepower.

Replace the factory control chip on the electronic control unit with an aftermarket performance chip. The chip alters the engine's software, leading to more horsepower and better performance overall.

Replace the factory exhaust system with an aftermarket system, from the catalytic converter to the tailpipe. Since the aftermarket exhaust pipes are wider than the factory exhaust, it improves the flow of exhaust fumes. Not only does this help increase the horsepower but it makes the vehicle sound deeper and more aggressive.

Use only premium fuel. Not only does high-octane fuel increase the horsepower but in can improve your gas mileage.

Items you will need

  • Socket set

  • Spark plugs

  • Oil

  • Oil filter

  • Air filter

  • High-performance air-intake system

  • Aftermarket performance chip

  • Aftermarket exhaust system

 How to Increase Horsepower on a Dodge Dakota

Remove the stock air intake box and replace the unit with a high-performance cold-air intake system. The stock box on the Dodge Dakota significantly restricts the amount of air that can flow through the vehicle's throttle body and into the intake manifold. A cold-air intake allows an air filter to sit out in the open inside of the engine bay, eliminating the need for a plastic housing container. The stock air intake box can be removed in under 30 minutes with basic tools. Loosen the bolts holding the box to the fender well, then loosen the clamp holding the air intake hose to the box. Install the cold-air intake using the factory provided instruction manual.

Replace the factory throttle body on your Dodge Dakota with a high-flow aftermarket model. The throttle body on your Dakota is responsible for allowing air into the intake manifold. The amount of air that passes through the throttle body is entirely dependent on how hard you press on the gas pedal. When the throttle body is fully open, however, it can only move so much air. A high-flow throttle body provides more cubic feet of air per minute into the engine's cylinders, allowing for stronger combustion and more horsepower. You can remove the stock throttle body by loosening the four bolts that hold it in place. Install the new throttle body and gasket via the included instructions.

Upgrade your Dodge's Engine Control Unit (ECU). The ECU is essentially the "brain" of your Dakota, and performs multiple tasks. An upgrade to your ECU will significantly increase horsepower levels by adjusting your transmission's shift points, timing and fuel mapping. You can find the ECU under the right side of your Dakota's dashboard. Aftermarket ECU program modules simply "piggyback" or click into the unit.

Items you will need

  • Socket wrench

  • Socket set

  • Screwdriver set

 How to Increase the Horsepower in a CTS Cadillac

Replace the factory exhaust system with a more performance-oriented aftermarket system. The wider diameter of the aftermarket exhaust piping will allow for an easier flow of the exhaust gases and will help the engine to produce more horsepower. In addition to increasing the horsepower output, the aftermarket system will produce a more aggressive exhaust note. Professional installation is recommended as access to a lift is necessary.

Upgrade the vehicle's air intake system with an aftermarket system designed to increase the flow of air into the engine. Aftermarket air intake systems increase horsepower and fuel economy by increasing the flow of cool air into the engine. This is accomplished by shortening the path of the air into the engine and through using less restrictive air filters.

Install an aftermarket performance chip into the vehicle's electronic control unit. The performance chip will alter the engine's computer management software to produce not only more horsepower but also improve the overall performance of the vehicle.

Items you will need

  • Aftermarket exhaust system

  • Performance chip

  • Air intake system

 How to Increase the Horsepower in a Honda

Install a cold air intake. Modern Hondas feature restrictive air boxes that prevent the engine from getting the proper amount of air. A cold air intake (CAI) replaces the air box with a larger diameter intake that is fed air through a large free-flow air filter. To install a CAI, unbolt the existing air box and disconnect the intake from the engine. Install the new intake according to the directions, which will vary depending on the brand you are using. Make sure the filter is positioned where it can get fresh air, away from the heat of the engine to realize the best results.

Install a performance computer chip or reprogrammed ECU. This will reconfigure how much fuel, spark and air the engine gets and in turn will increase horsepower. On older Hondas, it may be relatively straightforward to install a new chip, but current versions will need more advanced automotive diagnostic equipment for optimal results.

Replace the stock exhaust system with a larger diameter exhaust. Original equipment exhaust systems are smaller than optimal in diameter and prevent spent exhaust gases from exiting the motor as quickly as possible. A larger diameter exhaust system will allow the motor to run more efficiently and therefore allow it to produce more power. Exhaust system installation requires special equipment such as a lift, welding tool and metal-cutting tools and should be done at a professional exhaust shop by a technician experienced in installing exhausts.

Replace the manifold with a tubular header. This is a great complement to the larger diameter exhaust system. A tubular header helps get exhaust gases out of the engine more efficiently and allows the engine to make more power than the stock exhaust manifold, which has smaller than optimal internal passages with rough surfaces that restrict the flow of air. To install a header, unbolt the stock manifold from the head at the top end and the exhaust at the other end. The header bolts on in the same place as the manifold.

Supercharge or turbocharge the engine. Forced induction is a very common way to get big power out of a Honda. Both of these methods use a compressor, mounted on the intake side of the engine with a supercharger and on the exhaust it if is a turbo, to force more air into the motor. Both of these are quite complicated to install. This should be done at a shop or by a technician who is familiar with this type of conversion.

Items you will need

  • Socket set and ratchet

  • Specialty automotive tools

 How to Increase the Horsepower in a 53L Engine

Unbolt the stock exhaust system from your car or truck by first removing the bolts securing the exhaust to the catalytic converter. Use the socket set to continue unbolting the exhaust from the frame, including the exhaust hangers. Use a reciprocating saw to cut the exhaust tube so that it can be more easily removed from underneath the car or truck.

Install the dual exhaust system by first routing the exhaust pipes over the rear axle, then aligning them to the stock exhaust hangers. Application-specific exhaust kits will include exhaust hangers which fit into the existing stock exhaust hangers. Bolt the exhaust flange to the catalytic converter flange using the supplied hardware and the socket set to complete the installation.

Open the hood and remove the stock air filter and intake runner from the engine of the vehicle. The air box is bolted to the frame and core support, while the upper section of the intake runner is held in place with a compression band fitting attaching the air intake duct to the throttle body. Remove the mass air flow sensor and the intake air temperature sensor and lay them aside. Remove the air intake system from the vehicle.

Install the cold-air intake system by first fitting the intake "hat" over the throttle body and using the compression band with a screwdriver to tighten it into place. Then, install the intake air temperature sensor into the hole in the upper intake tube with the supplied rubber grommet. The mass air flow sensor is next, fitting into place with rubber compression boots and metal compression bands which are installed with screwdrivers. Finally, install the air filter cone into place at the end of the intake runner and near the core support of the vehicle.

Remove the negative terminal from the battery, then locate the engine management computer. The wiring harness is screwed into the computer to prevent accidental removal. Remove the screw, then pull the wiring harness straight out from the engine computer. The performance chip installs into the computer, then the wiring harness installs into the performance chip. Replace the screw and carefully tighten it down to secure the wiring harness in place.

Items you will need

  • 3/8 inch drive socket set

  • Reciprocating saw

  • Dual-exhaust system

  • Screwdrivers

  • Cold air intake

  • Reprogrammed computer chip

 How to Increase Horsepower in a Jeep 4.0

Replace the Jeep cold air intake with a performance aftermarket cold air intake. Performance aftermarket cold air intakes increase horsepower by enhancing the flow of cold air into the engine. They are relatively simple to install without professional assistance and are one of the least expensive performance upgrades available for Jeep vehicles. They may slightly increase engine noise, but are generally free from drawbacks when installed correctly.

Replace the Jeep exhuast system with a performance aftermarket exhaust system. Performance aftermarket exhaust systems increase horsepower by enhancing the flow of hot air out of the engine. They typically require professional installation as access to the underside of the vehicle is needed. They substantially increase engine noise, although many Jeep owners find the louder, more aggressive engine note desirable. However, they also increase emissions and may result in your vehicle losing street legal status in some states. Consult state regulations before performing this upgrade.

Install a forced induction kit onto your Jeep 4.0L engine. Forced induction kits increase horsepower by forcing large amount of air into the air/fuel mixture within the engine itself. They are relatively difficult to install and can be extremely expensive. They also reduce fuel economy, drastically in some situations, and increase overall wear and tear on your Jeep. However, they can more than double the horsepower of your Jeep depending on the size of the turbocharger that you install.

Install a nitrous oxide injection kit. Unlike other performance modifications, nitrous oxide injection kits do not permanently change the functioning of your car. They allow the driver the inject a shot of nitrous oxide into the fuel system with the push of a button or the pull of a level, which provides a large but temporary boost to available horsepower. Such kits are typically designed for straight line racing, and like forced induction kits they will increase overall wear and tear on your Jeep when activated.

 How to Increase the Horsepower of a Northstar

Modify the electronic control unit controlling the Northstar engine's functions by attaching an aftermarket performance chip. The performance chip will alter the software that controls the engine so that more horsepower is produced. Many chips will also improve overall performance by altering the fuel and ignition maps and raising the rev limit.

Replace the existing air intake filter with an aftermarket model designed to improve the flow of air into the engine. In addition to allowing for more horsepower output, the less restrictive aftermarket filter will improve the vehicles fuel economy.

Install an aftermarket exhaust system in place of the factory system. The aftermarket system will improve the flow of exhaust gases away from the engine and also reduce the overall back pressure in the exhaust system. Both changes will result in an increase in horsepower output.

Items you will need

  • Aftermarket air intake system

  • Performance exhaust system

  • Aftermarket performance chip

 How to Increase Horsepower in a Corvette

Purchase and install a performance aftermarket cold-air intake system. The Corvette's cold-air intake system is responsible for cooling and directing air into the engine. Performance aftermarket cold-air intakes are designed for maximum airflow, whereas the stock cold-air intake is fairly restrictive to reduce engine noise. Installing a performance aftermarket cold-air intake typically results in a boost of 5 to 20 horsepower, according to manufacturer claims, depending on the model and year of Corvette.

Purchase and install a performance aftermarket exhaust system. Exhaust systems allow warm air to flow out of the engine to maintain a lower engine operating temperature. As with cold-air intake systems, stock exhaust systems are fairly restrictive to minimize engine noise and emissions. Installing a performance aftermarket exhaust system can provide a power increase of roughly 10 to 40 horsepower, based on manufacturer claims. Note that doing so will typically make the engine louder and will increase the Corvette's emissions. Make sure to consult the automotive regulations for your state before installing an aftermarket exhaust system, as you may inadvertently cause your Corvette to lose its street-legal status.

Purchase and use a handheld flash tuner. Tuners can only be used on Corvettes that have an onboard computer. General Motors began putting onboard computers in its Corvettes in the early 1980s, depending on trim line. Tuners reprogram the vehicle's onboard computer, which can provide a moderate horsepower boost to a stock Corvette. More importantly, a tuner will maximize the horsepower gains of any aftermarket modifications you make to your Corvette. A Corvette with an onboard computer should be tuned after each installation of a performance aftermarket component.

Items you will need

  • Automotive tool kit

 How to Increase Horsepower on a Nissan Xterra

Replace the stock air filter with a quality aftermarket unit. Air filters are specifically designed to filter microscopic particles from the outside air before the air is drawn into the engine. Unfiltered, these particles can damage an engine over time. The disadvantage of an air filter is that it restricts the engine's ability to withdraw air. The Xterra's stock air filter adequately filters the air, but is restrictive. Aftermarket air filters are available that can filter the air just as well, if not better, than the Xterra's stock filter. The advantage to a quality aftermarket air filter, however, is that it is not nearly as restrictive as the stock filter. This means the engine does not have to work as hard to withdraw air. As a result, the Xterra's engine is able to produce more horsepower with an aftermarket air filter than with the stock filter.

Replace the stock exhaust manifold with an exhaust header or headers, depending on the particular engine. Whereas the engine must withdraw air through the air filter, it must expel the spent gases through the exhaust system. The Xterra is produced with either a four- or six-cylinder engine. The four-cylinder engine uses a single exhaust manifold to rout the exhaust gases away from the engine, while the six cylinder uses two exhaust manifolds. These manifolds severely restrict the Xterra's ability to dispose of the exhaust gases, due in part because the manifold pushes the gases from each cylinder together. This pushing force reduces the engine's power. An exhaust header provides each cylinder with its own exhaust pipe, which substantially eliminates the amount of power the engine must use to expel the exhaust gases, translating into an increase in horsepower.

Replace the engine's computer chip with a high-performance computer chip. The Xterra's engine is controlled by a computer chip, which controls the power produced by the engine. Replacing the computer chip may seem like an intimidating task, but the replacement process is actually quite simple, provided the manufacture's instructions are carefully followed. The high-performance chip is specifically designed to allow the Xterra's engine to produce more horsepower by altering the Xterra's timing and fuel supply.

Items you will need

  • Air filter

  • Exhaust header(s)

  • Computer chip

 How do I Increase Horsepower on a 440 Dodge Engine?

Send your engine to a machine shop to have it disassembled, cleaned and checked for cracks. Have the machine shop perform any required machine work, including (but not limited to) cylinder boring, align boring, cam boring, and block and cylinder head decking. Of these, cylinder boring and decking (milling the block and cylinder head mating surfaces flat) are the most crucial for this application.

Choose a supercharger-specific camshaft with a wide 114-degree lobe separation. You'll want to use a split-pattern camshaft with about 0.080-inch more lift and about 4 degrees more duration at 0.050-inch lift on the exhaust side than the intake. For a street engine with a stock crankshaft, purchase a cam designed to deliver power in the 3,500 to 5,500 rpm range. If you don't want to use a supercharger-specific cam, use a standard cam with 1.5-to-1 roller rocker arms on the intake valves and 1.7-to-1 rockers on the exhaust valves.

Purchase a set of 4340 steel I-beam connecting rods and forged pistons intended to deliver between 8.5 and 9.0 to one compression with your stock cylinder heads. Have the machine shop balance the rotating assembly (crankshaft, rods and pistons). If you're already having the block machines and the assembly balanced, you might as well pay the machine shop to assemble the long block (block and heads) for you. This will probably only add a few hundred dollars to the overall cost--a price well-justified by the peace of mind that a warranty brings. Have the machine shop install the mains with chrome-moly studs and the heads with Cometic gaskets and chrome-moly head studs.

Bolt the supercharger-specific lower intake manifold to the heads and bolt the supercharger to the manifold. Superchargers in this class are rated as either 6-71, 8-71 or 10-71; this rating system hearkens back to the days when hot-rodders took their superchargers from massive six, eight and ten cylinder diesel engines. Each of the engine's cylinders displaced 71 cubic inches, thus the rating system. A 6-71 blower will work for this application, but you'll probably be better off with an 8-71. Install the supercharger as per the kit instructions.

Top the engine off with a pair of 450-cfm, vacuum-secondary carburetors, an aftermarket distributor and coil, an ignition box with provisions for boost-regulated timing retard and a set of 2-inch primary headers.

Items you will need

  • Basic hand tools

  • Roots-Type Supercharger Kit

 How to Increase the Horsepower of an Acura MDX

Install a performance aftermarket cold-air intake system to replace the factory cold-air intake system. The cold-air intake system sucks in air from the environment, cools it, and directs it into the air/fuel mixture within the engine. Performance aftermarket cold-air intake systems engage this process more efficiently. This results in an increase of roughly eight to 15 horsepower, depending on the manufacturer of the cold-air intake system and which version of the MDX it is installed into. Cold-air intake systems typically cost between $100 and $200 and can be installed at home.

Install a performance aftermarket exhaust system to replace the factory exhaust system. Exhaust systems direct airflow out of the engine bay and out of the vehicle itself. Factory exhaust systems restrict airflow in order to minimize engine noise and emissions. Adding a performance aftermarket exhaust system will enhance airflow from the engine. This results in an increase of about 10 to 15 horsepower in the Acura MDX. Aftermarket exhaust systems typically increase engine noise, so be aware that your vehicle may sound louder if you opt for this upgrade.

Install a nitrous oxide injection system. Nitrous oxide systems inject nitrous oxide into the fuel system when a button or lever is pressed by the driver. Adding nitrous oxide to the fuel system provides a tremendous boost of horsepower, but only for a brief period of time because it is quickly used up. Nitrous oxide injection systems are typically designed with straight line performance, with activities such as drag racing in mind. Nitrous oxide systems can also be very hard on your vehicle if used frequently or improperly.

Items you will need

  • Automotive tool kit (if performing any upgrades yourself)

About the Author

This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Runs, contact us.