by TomB » Tue Jun 15, 2004 3:06 pm
Engine Tuning Guide to B16A's
The B16A appeared in the Japanese market for the 1989 model year. It was the first DOHC VTEC engine to hop into production. It made an immediate impact in the Civic, CRX, and Integra lines in Japan. The mighty 1.6 boasted 160hp and 111lbft of torque (Sir 167hp). Those numbers have remained, for the most part, unchanged in 11years.
Air Intakes
An air intake system is, in general, the first modification that people perform to their engine. An air intake system replaces the stock airbox with a more open-flowing design. Air intakes are generally put into 2 categories: Cold Air Intakes (CAI) and Short Ram Intakes (SRI). Opinions of which is the best design varies from person to person. Short Ram Intakes are generally cheaper than full CAI systems, but they do not produce the amount of highend power that the CAI produces. SRI's are known for providing faster throttle response than CAI because their tubing length is much shorter. They are also more popular for people in areas with good amounts of rain because the air filter sits inside the engine bay. While it stays away from water, it also sucks in hot air from the engine bay, which in turn inhibits performance and horsepower. SRI's are also well known for being louder than CAI's, once again, because of their short length. CAI's have filters that sit behind the front bumper of the car and in front of the front wheel. This positioning keeps them safe from water splash and allows for colder air to be taken into them. Colder air makes more power. CAI's also cost more than SRI's because they use a little over twice the tubing that the SRI does. Comptech's Icebox takes the best of both worlds. It takes air in from behind the front bumper, however the filter is mounted halfway up the pipe around the position that the SRI's filter is.
Popular manufacturers of CAI systems include AEM, Comptech, and Injen.
Popular manufacturers of SRI systems include: AEM, Mugen and Weapon R
Intake Manifold
An intake manifold allows the higher airflow from an aftermarket air intake to flow into the engine with more flow and in more amounts. The intake manifold is commonly overlooked as a part of the
engine to modify. However, it is vital to allow the engine push more air in, to produce more power and an intake manifold allows that to happen. There are pretty much 3 options for intake manifolds which will give you higher flow. An intake manifold off of a B18C5 (Integra Type R) engine will give you better flow. For a little more you can get even better flow with the Skunk2 Intake Manifold. It is designed like the B18C5's only it allows more flow because the runners are bored out slightly more. For still more you can pick up the Edlebrock Intake Manifold which has the design of an F2000 racer more than an OEM look.
Exhaust Headers (Manifold)
An exhaust header takes the exhaust air from your engine and sends it to the exhaust. It is crucial to have a very efficient header on a B16 because of the amount of air that it moves while in the VTEC range. Headers come in 2 varieties: 4-into-2-into-1 (4-2-1) and 4-into-1 (4-1). The difference lies within their piping design. A 4-2-1 header goes from 4 tubes right off of the head, those 4 tubes turn into 2, and then the final 2 tubes merge into 1. A 4-1 design has the 4 tubes off the head converging into 1. Ususally this occurs at the collector, or the end of the header where it meets the catalytic converter. In general 4-2-1 header designs yield good low range and midrange output. The 4-1 lacks the gains on the low range but will give good mid range and incredible high end gains. For this reason, it is recommended that for general road use, a 4-2-1 is the best way to go, as it gives a more rounded drive. A 4-1 is best for fast driving such as track days. A difference can also be found in the bend design. A header bent on a mandrel will typically yield greater gains than a basic crimp bend, due to greater flow. It appears the longer the header takes to combine into 2 tubes, the better it does in the low and midrange. DC Sports' 4-2-1 design has the header combine into 2 about 1/2 way in the design. That header gives fairly dissappointing numbers and it only bumps stock horsepower by about 4 or 5 horsepower to the ground throughout the whole powerband. However, Comptech's 4-2-1 header produces dyno graphs like DC Sports' 4-1 header. This is achieved by Comptech making their header combine into 2 about 3/4 of the way down the header. By doing this, it flows air quickly like a 4-1, but
it also combines the air more smoothly like a 4-2-1 configuration. Toda, SMSP, and Spoon use just about the same style of 4-2-1 header.
Popular 4-2-1 header manufacturers include: DC Sports, Comptech, SMSP, and Spoon.
Popular 4-1 header manufacturers include: Honda of
Japan, DC Sports, OBX and Mugen.
Exhaust
An exhaust is a personal finish to your basic upgrades on your engine. Exhausts generally come in 2.25", 2.5", and 3" varieties. The trick to picking the best exhaust is not to have the highest flow, but to have the correct flow for your application. Yoou need to keep delta pressure in the exhaust piping to allow for exhaust to flow correctly. Having too little delta pressure will make the engine backfire because the exhaust will create a reverse vacuum. Having too much delta pressure will cause exhaust gas to become too backed up to flow out in a quick enough manner. With just basic upgrades to your engine, which doesn't include any internal modifications, 2.25" exhaust is probably best for your application. It will give higher flow, but not too much flow considering your small amount of upgrades. Popular 2.25" exhausts include Apexi World Sport and Tanabe Hyper Medallion. If your B16 is running a supercharger or internal modifications like cams or pistons, you'll want to run a 2.5" exhaust system. The bigger exhaust system allows for more flow because you are now moving more air than with just basic upgrades. Popular 2.5" exhausts include Spoon N1, Apexi N1, and GReddy EVO. A 3" exhaust system is usually reserved for turbocharged B16s. The bigger exhaust allows for more horsepower because it can flow a lot of air, fast. Other exhaust options include having a custom exhaust made by a specialist like Powerflow, Blue Flame or Longlife.
Cam Gears
One of the easiest ways to tune your engine for better power is by adjusting the cam timing using cam gears. Aftermarket cam gears appear like stock cam gears, however aftermarket ones can allow the
owner to advance or retard the cams timing using marks on the gear. An advanced timing setting is used for naturally aspirated applications, while retarding the timing is used on turbo or supercharged engines. Many companies produce cam gears including AEM, Skunk2, Spoon, and Toda.
Cams and Springs
Another easy way of obtaining an increase is to replace the standard cams with those of other models. These can be from the Jap only CTR or the ITR. These will both fit a B16 and give a nice boost. It is also wise to uprate the valve springs at the same time. There are many 'wild' cams available as well. These will give huge increases but will need more modifications to give the best they can. By this I mean higher compression pistons, uprated rods and all the springs and retainers uprating.
These are made by Spoon and others.
Mix 'n' Match
It is possible to replace whole sections of the engines. A B18 bottom and with a B16 head is said to give good results. A H22 will also fit with a bit of work and will give a whopping increase. I will try to find more on these and add to later.
This has been pieced together from various sources and may not all be accurate. In general though, I think it is valid. Hope it helps in some way.
Please feel free to comment on any aspect of it, as I will not take any offense and would be pleased to know where I went wrong.
Last edited by
TomB on Tue Jun 15, 2004 5:37 pm, edited 2 times in total.
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