I/H/E Basic Information

[imported_Slick]

I found this on ClubSI.com and found it very informative for anyone new to tuning and wanted to learn the basics, anyone who wants to know of some good brands, sizing/diameters, or where to go after the basic bolt ons.

Intakes
The philosophy behind an intake system is the colder the intake charge, the better. There is a variety of Intake Systems available for the EM1; there are Cold Air Intakes (CAI), Short Ram Intakes (SRI) and Filter Box Intakes (FBI). CAI is an intake that goes from the throttle body all the way to the front of the vehicle, usually to the passenger's side inner fender-well behind the front bumper. A SRI (AKA, filter on a stick) is just a pipe from the throttle body to a forward location usually ending up above the transmission or behind the headlight. A FBI is an intake system the either retains the stock filter box, or incorporates a custom filter box. Within those 3 main categories, there are several different variables to distinguish an Intake system, those variables are Filter Element, Piping Material, Pipe Diameter, Pipe Shape, Inlet Location/Air Temperature and Box Size. Below, I listed some ways to figure out how to determine a good intake from a not-so good intake.

Inlet Location - This is an important part of the function of the intake. An intake the pulls it air from a cooler location will work the best. I have seen some SRI's that place the filter directly behind the radiator. With it there, the only air it will be taking in is hot air. Remote locations are great, or a location that blocks it from the hot air.

Filter Element - There are 3 main types of filter elements, paper, foam and the K&N type material filter. The main focus on the filter element is the restriction of air flow. Between the K&N type and foam filter there really is no difference both are very free-flowing. A paper filter is basically what comes stock and is very restrictive.

Piping Material - Since the piping is what transfers the intake charge from the inlet (filter) to the throttle body, it's good to have a material the will not transfer heat. Aluminum seems to be the most popular used, but aluminum does transfer a lot of heat through itself. Steel is sometimes found in the DIY intakes, although it takes a lot of heat in order for it to transfer through, the steel will stay warm longer than the aluminum. Plastic transfers heat and holds the heat; I don't even know why companies even use plastic. Aluminum seems to be the best material. Of course you will find some made with C/F, like the J's Racing intakes, these also seem to work very well.

Pipe Diameter - The wider the better, a lot of intakes use 2.5" diameter (i.e. AEM's infamous CAI), what seems to work the best is something that is 3" in diameter. This seems to move a lot of air and not restrict velocity.

Pipe Shape - I have seen some crazy things in my lifetime, but some of the intake shapes that I have come across completely boggle my mind. I have seen some intake that look like they are just exploding the in middle with crazy bulges and what not. They claim it increases velocity using aerodynamics, but I think that they are smoking some crack. Straight flow-through designs are efficient.

Box Size - This is for the FBI type intakes, basically, the larger the box, the more efficient.

Popular Intakes:
Manufacturer / System Type / Filter Type / Piping Material / Piping Diameter
AEM / Short Ram / SRI / K&N / Aluminum / 2.5"
Injen / Intake System / SRI / K&N / Aluminum / 3"
J's Racing / SRI / K&N / Carbon Fiber / Varies
AEM / CAI / CAI / K&N / Aluminum / 2.5"
AEM / V2 / CAI / K&N / Aluminum / 4"
Injen / Race Division / CAI / K&N / Aluminum / 2.75"
Comptech / Ice Box / FBI / Foam / ABS/Aluminum / 3"
Mugen /none / FBI / K&N / ABS / N/A

Atmospheric conditions have a direct effect on your engines output. Hotter, less dense air will do nothing for your engine, expanded air does not add more air to the mix, and it only takes up more space that could be used for more air. Cooler, denser air will allow more air to be added with the fuel. Keep in mind, that every 11 degrees F you lower your intake air temperature, you gain approximately 1% horsepower increase. So, if the under the hood temperature is 200 degrees F, and the atmospheric temperature outside is 68 degrees F and you duct the outside air in, you just bumped your horsepower from 160hp to 179.2hp.

A wonderful question often brought up about cold air intakes is, "Will a cold air intake hydro-lock my engine?" Well, to answer that question, yes and no. I personally ran a cold air intake year round, through driving rain storms and Northeastern Ohio blizzards. Never have I hydro-locked my engine. However, I have heard of stories of people hydro-locking driving through shallow puddles. Although I really do not understand how it could happen seeing how I have driven through puddles as deep as 6 inches, some precautionary tactics may want to be taken to avoid the possibilities of a hydro-lock situation. One tactic that can be used is when driving through a deep puddle, push in the clutch and let off the gas. This will eliminate the intake vacuum and lower your chances of giving your engine a drink.

To install most intakes, you'll need a 10mm socket, 12mm socket, flat head screwdriver, #2 phillips screw driver and needle nose pliers. Most CAI's require the removal of the front bumper for installation. Set aside 2 hours for installation for first-timers.

Headers
A good header will give you the most power out of the 3 basic bolt ons. The is a variety of shapes and sizes of headers, the 2 main categories are 4-2-1 & 4-1. This is referring to the how the primaries step down to the collector. There are also different sized collectors, primaries and secondaries as well. A 4-1 header is designed to give more power at higher RPMs and a 4-2-1 header will give more power at mid-range RPMs. Large primaries and large collectors are a plus, 1.5"-1.75" primaries on a 4-1 along with a 2.5" collector is the supreme choice for Supercharger equipped EM1's. Larger primaries are not as great on N/A EM1's, but the larger collector is always a plus. The other things to look for are ceramic and stainless steel. Ceramic will look dull and tends to rust fast, stainless is shiny and will bronze from heat. NOTE: a 2.5" collector will require an after-market catalytic converter to accept the collector.

Popular Headers:
Manufacturer / Design / Collector Size / Material
DC Sports / 4-1 / Stock / Ceramic/Stainless
DC Sports / 4-2-1 / Stock / Ceramic/Stainless
DC Sports / JDM 4-1 / 4-1 / 2.5" / Ceramic/Stainless
'98 Spec JDM ITR / 4-1 / 2.5" / Mild Steel
Comptech / none / 4-2-1 / Stock / Stainless
APEXi / GT / 4-2-1 / Stock / Stainless
Kamikaze / 4-1 / 2.5" / Ceramic
GReddy / none / 4-2-1 / Stock / Stainless
Mugen / none / 4-1 / Stock / Stainless

if completely wild, big gains is what you're looking for, look into the Erik's Racing headers for equal length priaries.

You will need 10mm, 12mm, 14mm sockets, and 19mm open wrench (for O2 sensor). Allow 3 hours for first-timers.

Exhausts
Cat-Backs are the Cat's ass. Exhausts are generally sold as cat-backs, tail-sections and universal mufflers. A cat-back system goes from the catalytic converter all the way to the muffler tip. A tail section (AKA, axle back) goes from the axle to the muffler tip. A universal muffler? is just a muffler. The most important thing to look for in an exhaust is 60mm or 2.5" piping from the cat-back for N/A and 3" for boosted cars. You don't want to go too small on the piping because it will be too restrictive. Too large of a piping will and your exhaust gases will loose velocity. Retaining the stock piping gets you no gains. The muffler is not a factor on performance, the only thing to look for in a muffler is your sound preference and make sure it is a free flowing muffler.

Popular Cat-Back Exhausts:
Manufacturer / Style / Piping Diameter / Piping Material / Muffler Material
APEXi / N1 / 60mm / Aluminized / Stainless
APEXi / WS / 60mm / Aluminized / Stainless
GReddy / EVO / 60mm / Aluminized / Stainless
Thermal R&D / Classic / 2.25" / Stainless / Stainless
Thermal R&D / Stealth / 2.25" / Stainless / Stainless
Thermal R&D / Turbo / 3" / Stainless / Stainless
Mugen / TL / 60mm / Stainless / Stainless

You will need 12mm and 14mm sockets. Allow 4 hours for installation and be prepared for broken bolts.

A high flow cat or test pipe will compliment your 3 basic bolt ons rather nicely.

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Which intake makes the most horsepower?

Look through the posts, look at the dyno's, the intake that usually makes the most hp is a short ram. For some reason the DC-Sports and Injen short ram usually come out on top.

Before everyone hops on and starts talking about how this intake dyno'd more gain than this intake, keep in mind a dyno is usually done with the hood OPEN, and a generally cold temperatures in the engine bay. When your hood is closed, it gets very, very hot.

Thus, a CAI will provide more gains. Also look at material of the intake, does it conduct heat well? Although originally mandrel metal bends, the AEM and most intakes have special coatings against heat.
Other things to make your intake charge cooler: Hondata Intake Manifold gaskets. Your engine heats up, and heats up your manifold, the oem gasket doesnt deflect heat transfer at all. Coolant from the engine also heats the manifold up. Hondata used to make manifolds with the "race" option, to keep all coolant out of the manifold, but has since changed their design to only let the coolant flow in. I believe ANR makes a similair gasket for less cost, but different material.

If you want my personal opinion, it's just an intake. All arguements are over a difference of 2-3whp. So above all, what may matter to most, is throttle response. In the world of throttle response, an AEM CAI would be dead last, and something with a very big airbox, like the ARC piece, or the J's racing intakes.

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Throttle Body
After the intake, the next thing the air passes through is the throttle body; a larger throttle body will help increase the volume of air traveling to the engine. But keep in mind, bigger may be better, but biggest is not the best. Too large of a throttle body and you will loose the velocity of the intake charge. A good size for most natually aspirated B16's is 62mm. 65mm is good if the IM is modified and some head work. 70mm is for all out raging fun. It is highly recommended to port-match the intake plenum to the TB for excellent results.

Popular Throttle Bodies
Manufacturer Size
Integra Type R 62mm
Spoon 70mm
Inline Four 70mm

Intake Manifold
After the throttle body, the air is moved through the intake manifold. The stock intake manifold on the EM1 is great, but there is always room for improvement. Air flows like water, to the path of least resistance. Straight, rounded passage ways allow for faster flow of air. A square shape passageway will allow a greater amount of air to flow. But if either of those passageways has to have a bend in it, the air flow begins to tumble, creating turbulence and causing restriction. The funny thing is, with a hybrid shape of round and square, you get a D shaped passageway. What happens there is you get volume and velocity, and if a bend occurs and you have the rounded portion on the radius side, you limit the turbulence. An intake manifold can be improved upon further by cleaning up the walls and smoothening some of the corners of the bends out. The IM can be Extrude-Honed, which is a process of forcing a heavy liquid with a cutting median in it. The liquid will form passage ways to allow ideal flowing conditions without removing too much material.

An intake manifold from an Integra Type R bolts directly up and offers a mild polish. This design is so good, that Skunk2 decided to copy it and resell it as their own intake manifold. There are a handful of other companies out there that make manifolds, basically what you are looking for is a larger plenum and straight runners.

Popular Intake Manifolds
USDM Integra Type R
JDM Integra Type R
Skunk2
Venom
JG
RPS

All credit here goes to http://www.clubsi.com for this write up.