All Motor modifications explained "What should my next mod be?"

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For Naturally Aspirated Set-ups

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

Air Filter/Intakes

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. Performace air filters are available for almost any application. K&N is the undisputed leader in the aftermarket high flow air filter business, and make a high quality filter for virtually every Honda on the market.

The next step towards improving the breathing of your engine is a full replacement of the stock intake system. There are many companies that manufacture aftermarket intake systems, and everyone has their own opinion of which one is best. Most aftermarket intakes that do include a filter with the purchase of their intake, that filter is made by K&N.

Exhaust Systems

The stock exhaust system found in most vehicles is a source of great flow restritcion. By replacing the exhaust system, you will discover a mild increase in power. The simplest, 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 use larger-than-stock diameter tubing, which is mandrel-bent rather than crush-bent to eliminate crimping where the tubes are bent, which allows for smoother and faster exhaust flow. Several manufacturers produce cat-back exhaust systems specially made for each model.

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. You also have the choice between single or dual tipped mufflers.
The #1 item that determines exhaust tone and volume is, of course, the muffler. There are 3 different internal construction styles of mufflers; chambered, straight through, and twin loop. Each one has it's own advantages/disadvantages, picking which combination of advantages vs. disadvantages is best for your car is your desicion, based on what tone you like, what volume you want to put up with, and your budget.
Here are the 3 styles:
-Chambered: This is the stock method of muffler construction for nearly every car on the road. There are many baffles and chambers inside the muffler to absorb as much sound as possible before allowing the exhaust to escape out the tailpipe. The downside to this method is all these obstacles stunt exhaust flowspeed, particularly in the upper RPM's. There are a few aftermarket manufacturers that use this style of muffler, such as Apexi (the WS line only), and RS*R. Although they are chambered, their design is not as restrictive as a stock muffler.
-Straight through: The majority of aftermarket exhausts use this style of muffler. There are no restrictions to exhaust flow inside the muffler, it's a straight unimpeded shot out the exhaust tip. The downside to this style is a higher volume exhaust tone. How much volume depends on the size of the canister and what type of material it is packed with.
-Twin Loop: Also called "twin pass". These mufflers are a straight through style muffler internally, but the exhaust passes through the muffler body twice to further absorb sound, at no sacrifice to flow speed. You get the quieter tone of a chambered muffler, with the flow ability of a straight through, without the extra noise. It's the best of both worlds, but these mufflers tend to be the most expensive on the market.

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.

Computer "Piggyback" Systems/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. If your engine has been heavily-modified, you will need a chip which has been programmed for your application, using systems such as Hondata, AEM EMS, or Uberdata. These systems make changes easy, as they can control ignition timing, fuel injection performance, air/fuel ratio, VTEC point, redline/fuel cutoff, and even automatic transmission shifting points.

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.

Piggyback systems are not a reprogramming of the ECU, as the above systems are. A piggyback system works by altering engine sensor inputs to the ECU, to "fool" the ECU into believing the engine requires more or less fuel, air, or spark. The most popular piggyback system for B series Honda engines is the Apexi AFC (for non-VTEC engines) and V-AFC (for VTEC engines). Tuning with a piggyback system cannot compare to the preciseness of tuning ECU chips/reburns provide, and engines with more advances modifications cannot perform to their potential, or may not be able to run at all, using a piggyback system.

Underdrive Pullies

Underdrive pullies usually consist of crankshaft and alternator pullies. These increase horsepower by reducing power robbing parasitic 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.

Exhaust Headers

Aftermarket headers can be bolted in place of the stock cast-iron headers. An important consideration when choosing headers is quality of materials. Header tubing varies 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.

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 such as Magnaflow, OBX and Random Tech. 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 most owners building a naturally aspirated engine experience little or no difference with a new ignition system, others find mild gains in fuel economy and power. The stock Acura Integra ignition system (as long as in good condition) is more than capable. There are 10 second B series motors using the stock ingnition.

Intake Manifold 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, Skunk2 or Blox), blue-printed throttle bodies, or TBI spacers.

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 new cams. Roller camshafts offer a smoother idle, a broad power range, and strong top end, but they are 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.

Thank you
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