Want more power? (Naturally aspirated)

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Naturally Aspirated

Note: The following list is ordered from simple to complex methods depending on how far you want to go with your vehicles performance.

Air Filters

The first and fastest way to get more power out of any engine is to get more air into the engine and more exhaust out. A high-flowing, low restriction air filter setup is the way to start. Perfornace air filters are available for almost any application. Horsepower gains vary, but you can expect a 5-10 horsepower gain in most applications.

Exhaust Systems

The stock exhaust system found in most vehicles is a soruce of great flow restritcion. By replacing the exhaust system, you will discover a dramatic increase in power. The simple, and most popular method to gain some power is to install a cat-back exhaust system, which replaces the stock exhaust from the catalytic converter to the tailpipe. These systems incorporate a high-flow muffler and often use larger-than-stock diameter tubing, which is mandrel-bent to eliminate crimping when the tubes are bent. Several manufacturers produce cat-back exhaust systems specially made for each model.

There are a few important things to consider when choosing a system for your truck. The material used in a cat-back system is usually aluminized steel. Aluminized steel exhaust systems are cheaper, but they won't last as long as stainless steel. For maximum durability, and if you can afford it, choose a stainless steel exhaust.

Exhaust systems vary greatly in exhaust tone, in-car noise, and fit. Keep those things in mind when deciding on your exhaust system. Another consideration is the exit location of the exhaust. Several manufacturers offer rear or side exit systems. You may also have the choice between single or dual-exhaust outlets. If you plan on installing your own cat-back system, remeber that although the new exhaust may be a simple bolt-on operation, removal of your old system may require cutting.

If a cat-back system isn't available for your application, you can purchase a high-flow muffler and fabricate your own system using larger-than-stock tubing, or have your muffler shop build one for you. A good cat-back exhaust or high-flow muffler can add up to 15-20 horsepower to your engine, and may also help with fuel economy.

For a mild boost of power, start with a high-flow air filter and a cat-back exhaust system.

Computer Chip Upgrades

If your engine is controlled by a computer, chances are you can gain power and performance by installing a computer upgrade. Most vehicles can use a replacement PROM (Programmable Read Only Memory) chip. These chips can alter the air/fuel ratio, idle speed, and spark timing of your engine depending upon different operating conditions. Most changes occur at or near wide open throttle. Most chips sold by large manufacturers are made for stock or near-stock engines. Examples include ADS, Z Industries, Hypertech, and JET. If your engine has been heavily-modified, you will need a chip which has been programmed for your application, some chip manufacturers, such as Z Industries, allow you to specify parameters and can make custom chips, or change a chip's settings.

Some systems make changes easy, and they can control ignition timing, fuel injection performance, and even automatic transmission shifting points.

Computer chips and reprogrammers can add up to 20-30 horespower, especially if you have already added a cat-back exhaust system and performance air filter. Some chips and reprogramming units require the use of premium gasoline, which may be an important consideration if you want to keep your fuel costs down.

Underdrive Pullies

Underdrive pullies usually consist of crankshaft and alternator pullies. These increase horsepower by reducing accessory drag. Pullies can benefit almost any engine, large or small. Installation is a snap, but there are a few disadvantages to underdrive pullies. Because the alternator is turning slower, it won't be able to produce the current needed to keep the battery charged when running at idle. If you leave your vehicle on idle for extended periods of time, you may want to only install the crankshaft pulley. An underdrive pulley set can add up to 15 horsepower to your engine and can also improve fuel economy.

Exhaust Headers

Aftermarket headers can be bolted in place of the stock cast-iron headers. Small block headers usually use 1-5/8-inch primary tubes and big-block headers use 1-3/4-inch tubes. An important consideration when choosing headers is quality of materials. Header tubing vary in thickness, but a good quality header should use between 18-gauge and 14-gauge tubing. The metal used in the header is also important. Some headers are mild-steel, which will rust and corrode over time. Headers can be coated, either with a ceramic coating or a high-temperature paint. Using 100% stainless steel construction eliminates the need for coatings, but it is usually out of many buyer's budgets. When headers are shipped, they sometimes come painted. Be aware that this coating is only for rust prevention during shipping, and the paint will not hold up to the heat once the header is installed. When headers are added along with a cat-back exhaust and high-flow catalytic converter, you can usually gain 20-30 horsepower over stock.

Catalytic Converters

When installing headers, you should add a monolith-style catalytic converter to replace the stock unit. Old or plugged pellet-style converters should also be replaced. Federal and state laws do allow the replacement of catalytic converters, but removal is illegal, and can actually harm your stock engine's performance. High-flowing performance catalytic converters are available from many companies. Be sure the catalytic converter you buy is made for your engine size, installing a 4-cylinder converter on a V8 will have a negative impact on exhaust flow. Another consideration is the material used in construction. The body of a catalytic converter is usually made of stainless steel, but the inlet and outlet tubes are often made of mild or aluminized steel. If you care about the longevity of your exhaust system, find a high flow catalytic converter that has stainless steel inlet and outlet tubes.

Ignition Systems

Ingition systems are also another source of added power. A performance iginition control can increase spark output over the whole power range. A complete ignition system upgrade should include new wires, and the spark plug gap may need to be increased to take advantage of performance ignition system. Older vehicles usually benefit more than newer ones. Although some owners experience little or no difference with a new ignition system, others find mild gains in fuel economy and power.

Intake Upgrades

Most late-model vehicles with electronic fuel injection use a TBI (throttle body fuel injection) system. TBI engines can benefit from the addition of a high flow intake manifold (such as those produced by Edelbrock), blue-printed throttle bodies, or TBI spacers. Companies such as Turbo City, Arizona Speed and Marine, and others offer several Chevy Small Block and Big Block TBI upgrades. For an even greater increase in power, a tuned port fuel injection system swap is available for those with TBI.

Cylinder Heads and Camshafts

Free-breathing cylinder heads are a good source of power. An alternative to expensive performance head replacements is to have your stock heads extrude-honed. This process will smooth out the intake and exhaust ports and will greatly improve flow characteristics, at a fraction of the cost of new heads.

Camshafts can also greatly improve your engine performance. There are many things to consider when installing a new cam. Roller camshafts offer a smoother idle, a broad power range, and strong top end, but they are much more expensive than standard flat tappet cams. A standard hydraulic cam is still a good choice, and proper planning will reward you with strong and reliable power. For a daily-driver, with compression between 9.5:1 to 10.0:1, 215 degrees is about the maximum .050-inch duration. With a lower compression engine, below 9.5:1 no more than 210 degrees of intake duration should be used.

Source: http://www.howstuffworks.com

DISCLAIMER: The contents of this article are not necessarily the official views of, nor endorsed by, the owner of HondaClub(com).

[TJ213]

Are these HP gains accurate?

The ratings more basic mods seem very optimistic

[AP1fun]

You forgot ITB's.


Also, in one of those things it says for your truck. Thats where I think the HP numbers are kinda leaning off a little.

[TJ213]

ITBs, that stands for intaking trash by-air, right
(I thought they were bad because its easy to get debrie into the engine)

[AP1fun]

There is a screen to filter out most debris but you could get small matter in the motor. If your serious into racing it may be worth it.

[racer crx]

what about a webber carb?

[AP1fun]

Originally Posted by racer crx

what about a webber carb?

That would be Honda's pre 1992 and most of those have swaps or aren't making huge power numbers. Many swap to fule injection intake manifolds.

[Manny720]

the HP gains seem accurate, however that doesnt equal what you get to the wheels. 14 HP gains translate to like six wheel HP. Also he forgot about Upgrading your clutch and flywheel. Also dont forget your tires. Whats the point of having all that power if your riding on bald tires!

[popseekel]

i would like to do a modification to my 96 180i for extra power at a low cost. what would be the best option and where can i get the chips in south africa referred to in the article

[8695Beaters]

For underdrive pulleys, they usually come with the alternator and water pump pulleys, and you have to buy a separate crank pulley. That ends up adding like 3 hp to the wheels. And if oyur car is old, then it is truly a pain to remove the old ones. Most Hondas, and all current Hondas, use multi-port EFI, not throttle body. Losing a cat converter will add power, but only 2 or 3 hp, and is not worth the smogging hassle. Remember, we all have a responsibility wirth our cars. If you need the hp, then your car is really a turd. On 4 and 6 cylinder engines, especially Hondas, the power gains from individual parts is almost always in the single digits. Honda does a pretty good job building and deigning their motors, so the gains are just a bit here and there. Was this article copied from some V8 site? The Detroit V8s never moved out of the muscle car days, so they suck, which is why they always get big power gains. That and they move way more air. The engines are just poorly designed. Honda, build us a DOHC V8 from the F1/Indy/ALMS program! Show Detroit what technology can do!