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Discussion Starter · #1 · (Edited)
Here's some information I took from ClubRSX. I've been spending a few days reading their threads on turboing a car, and found this to be very interesting. Although some of this information might not apply to us, it's a good read and should be able to answer a lot of questions that come up on this site. So it's time to read!

b005t3drsx; said:
How do I build a custom turbo kit… Q&A Thread

Okay there have been a lot of questions and threads about custom turbo kits. And obviously people don’t want to search so maybe this will help. Below is a list of questions and some answers or links to sites that may help you. Please read through this before you go posting your own threads or asking stupid questions. If you disregard this and ask questions or post your own thread please be prepared to be flamed. If you do have a question please check the chat threads first. Btw if you think something needs to be added pm me and I will add it to the list.

Helpful turbo research links…
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Fuel Setup

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If you plan on running high horsepower applications then you for sure want to update your fuel setup so that you don’t max out your fuel system, and to prevent hitting fuel cut while boosting. The reason to upgrade your system is that as you put more air into the motor you need to add more fuel to compensate for the increased air (aka to keep your air to fuel ratio at a certain level). If you don’t increase your fuel capabilities then you can very well max out your injectors which can cause them to go out. The stock rsx injectors are 350cc injectors are “good” for applications up to 350 horsepower.

Fuel Pumps & Feed Lines
Most people go with either the Walbro250 or for extremely high horsepower applications they go with the Bosch fuel pump, There are debates as to if the A1000 is a good pump for our cars because some users have had problems with the a1000 fuel pump.. If you plan on running in the 500 horsepower range you can get away with a single intake walbro or even a intake and inline walbro fuel pump for more than that you can go with the Bosch Fuel Pump

The feed line is very important in the fact that it is what is responsible for delivering the fuel to the fuel rail. Without a large feed line a new fuel pump won’t do you any good, however a new feed line with a small fuel pump won’t do you any good either. I suggest either a -6an or -8an feed line. You can do either however, I would go with the -8an just because it’s like a condom it’s one of those it’s better to have it and not need it, than need it and not have it. Lol. Here are some parts you will need.
  1. You need about 8in of -8an rubber fuel line to run from the fuel pump to the top of the fuel pump assembly
  2. You need a -8an male to male hose connector with 90 degree bend.
  3. You will need about 10ft of -8an stainless steel braided line.
  4. Most all these parts can be found on summitracing.com

Fuel Pumps & Feed Line Purchase:

Fuel Filters
A Fuel Filter is “optional” in the since that if you don’t do it and something happens don’t complain cause you just asked for it. A lot of junk gets in your fuel tank. I found leaves and even sticks and stuff in mine. In order to keep this stuff from getting in you fuel lines a fuel filter is a good investment. It goes in the feed line. All you really need is the fuel filter assembly that uses a 10 micron filter, and connectors.

Links for Purchase:

Fuel Rail & Injectors
For the same reason you upgrade your fuel pump and fuel lines you want to upgrade your fuel rail and injectors. If you do the rail and injectors but not the pump and lines you haven’t helped yourself any and vice versa. All fuel rails are created equal so really it doesn’t matter which one you go with. The AEM is nice cause it’s got a cover that will hide all the wires and helps keep the engine bay looking nice. In my opinion it’s worth the extra money. Injectors however are a different story. So let’s talk about them. There are two types of injectors. Low impedance and High Impedance.

Low impedance injectors with a resistance of around 2.5-3 ohms, and high impedance injectors of around 12 ohms. This can easily be measured by a multimeter across the two electrical terminals. Early Hondas used low impedance injectors with a resistor pack. From about '92 to '96 Honda transitioned from low impedance to high impedance without a resistor pack. If you look at the specifications of the injector driver package, it indicates it can flow the amount of current required for low impedance injectors. What affects reliability is heat, which is a by product of the current flow. The greater the current, the greater the temperature. Reliability takes a long time to measure. Temperature is straightforward. Running low impedance injectors without a resistor box will substantially increase the temperature of the transistor driver IC due to the increase in current flow. The temperature increase will depend on your driving. If that temperature remains high enough for long enough the driver transistor will be damaged. So in conclusion either low impedance injectors. The only real injectors you would by that are low impedance that require the resistor box are the 1000cc injectors. Other wise you would just most likely buy 750cc or lower low impedance injectors which don’t require the injector box. In my opinion if you don’t plan on going over 500 just stick with the 750cc, installing the resistor box with the c104 junction connector is a royal pain in the ass.

Injector Purchase:

Return Line w/ Fuel Pressure Regulator
Perhaps one of the best upgrades is a fuel return line. This will allow you to keep the fuel pressure in the system at a desired amount. Even though you won’t see this when your driving it will help when you do turning. I would again recommend you go with the large -8an return line. For this you will need about 10 more feet of stainless steel braided line, and the connectors for your fuel pressure regulator and hooking the return line to the fuel rail. The ideal setting for your fuel pressure is around 40 to 50lbs.

Links for Purchase:

Fuel Setup Links:

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Turbo Manifolds

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Turbo manifolds are what replace you’re your exhaust manifold. It’s very important that you choose a manifold that fits your needs. There are two types of manifolds, there is tubular manifold and log style manifold. Tubular manifolds are known for allowing more free flowing exhaust gases while log manifolds can be more restrictive. However, you can expect up to 500 to 600 horsepower on a log style manifold. Those same power goals could be reached with a tubular manifold, but at a lower level of boost. That is the trade off of tubular manifolds vs log style manifolds.

Different types of manifolds (advantages/disadvantages log style vs. equal length)

Cast log style turbocharger manifold

Welded tubular turbocharger manifold

Manifold design on turbocharged applications is deceptively complex as there many factors to take into account and trade off
General design tips for best overall performance are to:
• Maximize the radius of the bends that make up the exhaust primaries to maintain pulse energy
• Make the exhaust primaries equal length to balance exhaust reversion across all cylinders
• Avoid rapid area changes to maintain pulse energy to the turbine
• At the collector, introduce flow from all runners at a narrow angle to minimize "turning" of the flow in the collector
• For better boost response, minimize the exhaust volume between the exhaust ports and the turbine inlet
• For best power, tuned primary lengths can be used

Log manifolds are commonly found on OEM applications, whereas welded tubular manifolds are found almost exclusively on aftermarket and race applications. Both manifold types have their advantages and disadvantages. Cast manifolds are generally very durable and are usually dedicated to one application. They require special tooling for the casting and machining of specific features on the manifold. This tooling can be expensive.

On the other hand, welded tubular manifolds can be custom-made for a specific application without special tooling requirements. The manufacturer typically cuts pre-bent steel U-bends into the desired geometry and then welds all of the components together. Welded tubular manifolds are a very effective solution. One item of note is durability of this design. Because of the welded joints, thinner wall sections, and reduced stiffness, these types of manifolds are often susceptible to cracking due to thermal expansion/contraction and vibration. Properly constructed tubular manifolds can last a long time, however. In addition, tubular manifolds can offer a substantial performance advantage over a log-type manifold.

A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds

Log manifold with a divided turbine inlet design feature

Welded tubular manifold with a divided turbine inlet design feature

The concept is to DIVIDE or separate the cylinders whose cycles interfere with one another to best utilize the engine's exhaust pulse energy.

Below are some examples of common Turbular and Log Style Manifolds

Full Race
Full Race is a tubular manifold that is considered to be the industry best. While I have no problem with full race, I do believe that people more often pay for a name than a product. All tubular manifolds are based on the same similar design. One advantage of going with full race is that they have been around a while, and they stand firmly behind their product. They are the most expensive manifolds on the market but also considered the be the best as well. Visit Full Race

Peakboost is considered the be the new kid on the block with their tubular manifolds, but they are giving full race a run for their money. Peakboost is a cheaper priced manifold, but the price decrease did not come with any sacrifice in quality. Peakboost is a good alternative for someone who wants a tubular manifold but can not afford full race. Visit Peakboost Site

A solution for people who do not want large horsepower potential or do not want to deal with tubular manifolds , there are the more restrictive yet still very efficient log style manifolds. These manifolds are a lot cheaper compared to tubular manifolds. If you are not worried about ultra efficencey or about high horsepower applications (aka over 500 whp) then a log style manifold will work for you. The revhard manifold is considered to be the best of the log style manifolds. Visit Treadstone aka Revhard Manifolds

The last and possible least manifold is the greddy manifold. To be honest I wouldn’t recommend this is because the t25 flange on this manifold makes your choice of selecting turbos very limited. This is a log style manifold and because of the flange type I would not recommend getting it.

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How a Turbo System Works
Engine power is proportional to the amount of air and fuel that can get into the cylinders. All things being equal, larger engines flow more air and as such will produce more power. If we want our small engine to perform like a big engine, or simply make our bigger engine produce more power, our ultimate objective is to draw more air into the cylinder. By installing a turbocharger, the power and performance of an engine can be dramatically increased.

So how does a turbocharger get more air into the engine?

1 Compressor Inlet
2 Compressor Discharge
3 Charge air cooler (CAC)
4 Intake Valve
5 Exhaust Valve
6 Turbine Inlet
7 Turbine Discharge

The components that make up a typical turbocharger system are:
• The air filter (not shown) through which ambient air passes before entering the compressor (1)
• The air is then compressed which raises the air’s density (mass / unit volume) (2)
• Many turbocharged engines have a charge air cooler (aka intercooler) (3) that cools the compressed air to further increase its density and to increase resistance to detonation
• After passing through the intake manifold (4), the air enters the engine’s cylinders, which contain a fixed volume. Since the air is at elevated density, each cylinder can draw in an increased mass flow rate of air. Higher air mass flow rate allows a higher fuel flow rate (with similar air/fuel ratio). Combusting more fuel results in more power being produced for a given size or displacement
• After the fuel is burned in the cylinder it is exhausted during the cylinder’s exhaust stroke in to the exhaust manifold (5)
• The high temperature gas then continues on to the turbine (6). The turbine creates backpressure on the engine which means engine exhaust pressure is higher than atmospheric pressure
• A pressure and temperature drop occurs (expansion) across the turbine (7), which harnesses the exhaust gas’ energy to provide the power necessary to drive the compressor

What are the components of a turbocharger?

The layout of the turbocharger in a given application is critical to a properly performing system. Intake and exhaust plumbing is often driven primarily by packaging constraints. We will explore exhaust manifolds in more detail in subsequent tutorials; however, it is important to understand the need for a compressor bypass valve (commonly referred to as a Blow-Off valve) on the intake tract and a Wastegates for the exhaust flow.

Which Turbocharger is Right for Me or more affectionately known as My Turbo & Me
Selecting the proper turbocharger for your specific application requires many inputs. The primary input in determining which turbocharger is appropriate is to have a target horsepower in mind. This should be as realistic as possible for the application. Remember that engine power is generally proportional to air and fuel flow. Thus, once you have a target power level identified, you begin to hone in on the turbocharger size, which is highly dependent on airflow requirements.
Other important factors include the type of application. An autocross car, for example, requires rapid boost response. A smaller turbocharger or smaller turbine housing would be most suitable for this application. While this will trade off ultimate power due to increased exhaust backpressure at higher engine speeds, boost response of the small turbo will be excellent.

Alternatively, on a car dedicated to track days, peak horsepower is a higher priority than low-end torque. Plus, engine speeds tend to be consistently higher. Here, a larger turbocharger or turbine housing will provide reduced backpressure but less-immediate low-end response. This is a welcome tradeoff given the intended operating conditions.

Selecting the turbocharger for your application goes beyond “how much boost” you want to run. Defining your target power level and the primary use for the application are the first steps in enabling your Garrett Performance Distributor to select the right turbocharger for you.

Journal Bearings vs. Ball Bearings
The journal bearing has long been the brawn of the turbocharger, however a ball-bearing cartridge is now an affordable technology advancement that provides significant performance improvements to the turbocharger.

Ball bearing innovation began as a result of work with the Garrett Motorsports group for several racing series where it received the term the ‘cartridge ball bearing’. The cartridge is a single sleeve system that contains a set of angular contact ball bearings on either end, whereas the traditional bearing system contains a set of journal bearings and a thrust bearing

Turbo Response – When driving a vehicle with the cartridge ball bearing turbocharger, you will find exceptionally crisp and strong throttle response. Garrett Ball Bearing turbochargers spool up 15% faster than traditional journal bearings. This produces an improved response that can be converted to quicker 0-60 mph speed. In fact, some professional drivers of Garrett ball-bearing turbocharged engines report that they feel like they are driving a big, normally aspirated engine. Tests run on CART turbos have shown that ball-bearings have up to half of the power consumption of traditional bearings. The result is faster time to boost which translates into better drivability and acceleration.
On-engine performance is also better in the steady-state for the Garrett Cartridge Ball Bearing

Reduced Oil Flow – The ball bearing design reduces the required amount of oil required to provide adequate lubrication. This lower oil volume reduces the chance for seal leakage. Also, the ball bearing is more tolerant of marginal lube conditions, and diminishes the possibility of turbocharger failure on engine shut down.

Improved Rotordynamics and Durability – The ball bearing cartridge gives better damping and control over shaft motion, allowing enhanced reliability for both everyday and extreme driving conditions. In addition, the opposed angular contact bearing cartridge eliminates the need for the thrust bearing commonly a weak link in the turbo bearing system.

Competitor Ball Bearing Options – Another option one will find is a hybrid ball bearing. This consists of replacing only the compressor side journal bearing with a single angular contact ball bearing. Since the single bearing can only take thrust in one direction, a thrust bearing is still necessary and drag in the turbine side journal bearing is unchanged. With the Garrett ball bearing cartridge the rotor-group is entirely supported by the ball bearings, maximizing efficiency, performance, and durability.

Ball Bearings in Original Equipment – Pumping up the MAZDASPEED Protegé’s heart rate is a Garrett T25 turbocharger system. With Garrett technology on board, the vehicle gains increased acceleration without sacrificing overall efficiency and it has received many rave reviews from the world’s top automotive press for it’s unprecedented performance.

Power Chart

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Turbos Continued

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Air/Fuel Ratio tuning: Rich v. Lean, why lean makes more power but is more dangerous
When discussing engine tuning the 'Air/Fuel Ratio' (AFR) is one of the main topics. Proper AFR calibration is critical to performance and durability of the engine and it's components. The AFR defines the ratio of the amount of air consumed by the engine compared to the amount of fuel.

A 'Stoichiometric' AFR has the correct amount of air and fuel to produce a chemically complete combustion event. For gasoline engines, the stoichiometric , A/F ratio is 14.7:1, which means 14.7 parts of air to one part of fuel. The stoichiometric AFR depends on fuel type-- for alcohol it is 6.4:1 and 14.5:1 for diesel.

So what is meant by a rich or lean AFR? A lower AFR number contains less air than the 14.7:1 stoichiometric AFR, therefore it is a richer mixture. Conversely, a higher AFR number contains more air and therefore it is a leaner mixture.

For Example:
15.0:1 = Lean
14.7:1 = Stoichiometric
13.0:1 = Rich

Leaner AFR results in higher temperatures as the mixture is combusted. Generally, normally-aspirated spark-ignition (SI) gasoline engines produce maximum power just slightly rich of stoichiometric. However, in practice it is kept between 12:1 and 13:1 in order to keep exhaust gas temperatures in check and to account for variances in fuel quality. This is a realistic full-load AFR on a normally-aspirated engine but can be dangerously lean with a highly-boosted engine.

Let's take a closer look. As the air-fuel mixture is ignited by the spark plug, a flame front propagates from the spark plug. The now-burning mixture raises the cylinder pressure and temperature, peaking at some point in the combustion process.

The turbocharger increases the density of the air resulting in a denser mixture. The denser mixture raises the peak cylinder pressure, therefore increasing the probability of knock. As the AFR is leaned out, the temperature of the burning gases increases, which also increases the probability of knock. This is why it is imperative to run richer AFR on a boosted engine at full load. Doing so will reduce the likelihood of knock, and will also keep temperatures under control.
There are actually three ways to reduce the probability of knock at full load on a turbocharged engine: reduce boost, adjust the AFR to richer mixture, and retard ignition timing. These three parameters need to be optimized together to yield the highest reliable power.

Wheel trim topic coverage
Trim is a common term used when talking about or describing turbochargers. For example, you may hear someone say "I have a GT2871R ' 56 Trim ' turbocharger. What is 'Trim?' Trim is a term to express the relationship between the inducer* and exducer* of both turbine and compressor wheels. More accurately, it is an area ratio. * The inducer diameter is defined as the diameter where the air enters the wheel, whereas the exducer diameter is defined as the diameter where the air exits the wheel.
Based on aerodynamics and air entry paths, the inducer for a compressor wheel is the smaller diameter. For turbine wheels, the inducer it is the larger diameter

Example #1: GT2871R turbocharger has a compressor wheel with the below dimensions. What is the trim of the compressor wheel?
Inducer diameter = 53.1mm
Exducer diameter = 71.0mm

Example #2: GT2871R turbocharger (part # 743347-1) has a compressor wheel with an exducer diameter of 71.0mm and a trim of 48. What is the inducer diameter of the compressor wheel?
Exducer diameter = 71.0mm
Trim = 48

The trim of a wheel, whether compressor or turbine, affects performance by shifting the airflow capacity. All other factors held constant, a higher trim wheel will flow more than a smaller trim wheel.

However, it is important to note that very often all other factors are not held constant. So just because a wheel is a larger trim does not necessarily mean that it will flow more.

Understanding housing sizing: A/R
A/R (Area/Radius) describes a geometric characteristic of all compressor and turbine housings. Technically, it is defined as:
the inlet (or, for compressor housings, the discharge) cross-sectional area divided by the radius from the turbo centerline to the centroid of that area

The A/R parameter has different effects on the compressor and turbine performance, as outlined below.

Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.

Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing, as it is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel. This provides increased turbine power at lower engine speeds, resulting in a quicker boost rise. However, a small A/R also causes the flow to enter the wheel more tangentially, which reduces the ultimate flow capacity of the turbine wheel. This will tend to increase exhaust backpressure and hence reduce the engine's ability to "breathe" effectively at high RPM, adversely affecting peak engine power.
Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise. The flow in a larger A/R housing enters the wheel in a more radial fashion, increasing the wheel's effective flow capacity, resulting in lower backpressure and better power at higher engine speeds.

When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband characteristic.

Here's a simplistic look at comparing turbine housing geometry with different applications. By comparing different turbine housing A/R, it is often possible to determine the intended use of the system. Imagine two 3.5L engines both using GT30R turbochargers. The only difference between the two engines is a different turbine housing A/R; otherwise the two engines are identical:

1. Engine #1 has turbine housing with an A/R of 0.63
2. Engine #2 has a turbine housing with an A/R of 1.06.
What can we infer about the intended use and the turbocharger matching for each engine?

Engine#1: This engine is using a smaller A/R turbine housing (0.63) thus biased more towards low-end torque and optimal boost response. Many would describe this as being more "fun" to drive on the street, as normal daily driving habits tend to favor transient response. However, at higher engine speeds, this smaller A/R housing will result in high backpressure, which can result in a loss of top end power. This type of engine performance is desirable for street applications where the low speed boost response and transient conditions are more important than top end power.

Engine #2: This engine is using a larger A/R turbine housing (1.06) and is biased towards peak horsepower, while sacrificing transient response and torque at very low engine speeds. The larger A/R turbine housing will continue to minimize backpressure at high rpm, to the benefit of engine peak power. On the other hand, this will also raise the engine speed at which the turbo can provide boost, increasing time to boost. The performance of Engine #2 is more desirable for racing applications than Engine #1 where the engine will be operating at high engine speeds most of the time.

For more advance reading you can visit Turbos For Expert users

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Downpipes & Exhaust

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Downpipes and exhaust systems are the manner of moving exhaust gases out of the car. With or without a turbo you will want a way to move these gases from the exhaust side of the head out the back of the car. With a turbo system you will need a downpipe to take the exhaust gases from the exhaust side of the turbo housing to the exhaust system.

A downpipe is usually nothing more than a pipe that moves the exhaust gases from the turbo housing to the exhaust system. Depending on the type of turbo you went with most people will have either 2.5 or 3 inch downpipe. You can get downpipes from most turbo shops. On the site there are plenty of members who make custom downpipes. You can pm Kracker or Fade2Black to make you a custom downpipe.

Exhaust Systems
Exhaust systems are not as important as you think. You do want one that provides some back pressure but is also free flowing. Some people don’t put an exhaust system on and just ride around open downpipe. Although it sounds cool be prepared to be targeted by the police. In all honesty going to a local muffler shop and having them do a custom 3in exhaust is the most common solution for turbo exhaust. However, here are two links where you can buy exhaust systems and exhaust mufflers. Visit Exhaust Systems or visit Exhaust Mufflers. Btw please be aware you need to contact clubrsx to talk with a member of the staff for more details about the exhaust systems or mufflers before you make a purchase.

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Intercooler Piping

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Intercooler piping is the piping that runs from the compressor side of the turbo to the manifold. It’s what delivers the compressed air into the manifold. There are three types of ic piping. One is for tubular turbo manifolds, one of log style manifolds, and the other is custom. Unless you are a professional at cutting and measuring piping I would not suggest the custom even though it is the cheapest. If you want to make a custom piping kit you will need to talk to clubrsx because it’s a very detailed process.

Because of where the tubular manifolds place the turbo you need a certain intercooler piping kit. If you go with a full race or peakboost manifold you can use a full race or peakboost kit. The same goes for log styles kits. Log manifold piping kit is only good for the log manifolds. Obviously a custom kit is made to fit and will work for any manifold. Here are some links to visit for kits and custom piping information.

Purchasing Links

Reading Links

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Wastegates are simple yet important devices. They allow you to set a maximum boost that can be achieved. It works by letting exhaust gases by pass the exhaust housing so that the exhaust fan doesn’t spin as fast and therefore too much boost is not created. This amount of by passed boost is controlled by the spring in the in the wastegate. When the pressures from the gases exceed the pressure created by the spring the spring gives and opens a valve it was holding shut. This allows the gases to escape and by pass the turbo housing. There are two general size of wastegates. There are the 38 and 44mm wastegates. The size you get is determined by the manifold you choose. For example the treadstone manifold uses a 38mm wastegate. Please check with the store to confirm which wastegate your manifold supports.

Also wastegate springs measure resistance pressure in bars instead of psi. So to help you out I have placed a bar to psi conversion table.


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Blow Off Valves

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Blow off valves are essential to keeping a healthy turbo. They are also one of the main reason people love turbos is for the cool sounds the blow off valve makes. But it has a practical use as well. The compressor housing pushes compressor air through the intercooler piping into the intake manifold. This is good as long as the throttle body is open, but when you let off the gas the compressor air has no where to go and the pressure continues to build and can eventually start to push back against the blades of the compressor housing. To prevent this compressor surge the blowoff valve releases that pressure in the piping when the throttle body is closed. It uses a vacuum connection on the intake manifold to control when to release the pressure. Basically when the throttle body is closed and the last of the air in the manifold is sucked out it creates pressure inbalance. At this point there is more pressure in the piping than in the intake manifold. This pressure indifference is what causes the blow off valve to go into actions. Because there is more pressure pushing on the valve on the piping side than air from the manifold side, the valve opens up releasing that in the piping until the pressure is balanced once again. All blow off valves are the same it’s all dependent on what you want, and what sound you like.


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Intake Manifolds

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Intake manifold may seem like a non turbo mod but it can be a very helpful mod for our turbo cars. Honda actually makes a very efficient manifold, however they did not put it on the rsx. The manifold is called the RBC manifold. Most turbo users who want to get the most out of their system spend the extra money, to get the better free flowing manifold. If you decide to go with the manifold there are two parts you should go with. First is the manifold it’s self, and the second is the hondata intake manifold gasket. The manifold gasket is made to conduct less heat, and heat is the enemy of engines and power. You may ask your self why would you want to put the money into a new manifold, and the answer is you want to provide the best air for flow your engine. Imagine with the PRB manifold (stock rsx) your car has asthama, the rbc will fix that. It allows the car to breath better, and for a better air flow and air deliverence.


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Map Sensors

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Map sesnors are very important because they allow your ecu to read larger intake air pressures which are associated with boosted setups. Map sensors are pretty straight forward. Just besure you follow the installation guides because if you don’t you will destroy your mapsensor and you will have to buy a new one.


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Gauges are a debatable modification. Some people say that gauges are a ricers toy while others vouch for their capability to give the driver access to vital information about the car. There are a lot of different gauges out there. Below I have listed some of the most important gauges. You will need to choose how many gauges you want to run and then choose a piller pod to put the gauge in.

There are two types of boost gauges. One is an electrical gauge which measure the boost and then sends a signal to the gauge cluster that is correlated into a reading, the other is mechanical which has a hose which runs to the gauge from a vacuum source and displays the reading. Electrical is more accurate, but also more expensive. It is up to you as to which type you go with, and which manufacturer. You can see all the gauges that clubrsx sales here. If you want more help don’t be afraid to ask, or to call the store for help.

AEM Wideband EUGO Gauge
One of the most common gauges used by boosted car is the air to fuel ratio gauge. This gauge measure the ratio of the amount of air vs the amount of gas going into the motor. This gauge is important just to give you an idea of if your running rich or lean. To little gas and you won’t get the power you want, and to much gas you can hurt your motor by having to hot of an explosion. However most standard air to fuel gauges don’t have a wide enough range to boosted applications. This problem is overcome by the wideband eugo gauge. It gives the user the ability to measure lower a/f ratio values. You can get more information about the gauge, and purchase the gauge here AEM Wideband EUGO Gauge

Boost Gauge
This is without a doubt the most common gauge of all, however that doesn’t make it the most useful. This gauge is really more for appearance than anything else. It’s good for seeing your boost levels however, your boost is controlled by your boost controller. If want some examples see here Boost Gauge Showoff Thread

Fuel Pressure Gauge
Fuel Pressure is not one you see often. Most people ignore this one because they can get an idea of how their fuel system is acting by their a/f gauge. That is not true because you could have an air leak which will affect you’re a/f gauge, but your fuel system is fine. It’s totally up to the user to choose which gauges. They want. If you use your gauges for practicality then a fuel pressure gauge is important, if they are just for looks then not so much.

Oil Pressure Gauge
Last but not least is the Oil Pressure Gauge. This gauge is important because it’s important to keep a right amount of oil in your car. Without enough oil you motor will seize up. Because the turbo uses oil as well you often need more than the 5 quarts that is suggested by the user manual. As a result the gauge is a good way to measure how much oil is in the system.

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Vacuum Box

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An important part of a turbo system is having an adequate vacuum source for all your devices like boost gauge, boost controller, wastegate, map sensor, bov, etc… Because of this it’s hard to find adequate vacuum sources for all these devices. So there is a simpler way to handle all of this. The easiest way is to run one hose from the intake manifold to a vacuum box and from the vacuum box to the other devices. All you need to make it work is hoses, the block, and t fitting. You can get all of that here at the Forced Induction Accessories Page You will have to determine on your own how many slots you need and if you need to block any off. If you have any question about Vacuum Box’s please use the chat threads because these answer are usually pretty short and easy to resolve, so theres no need to waste server space with a new thread.

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The weakest part of this whole endeavor will be the part you probably planed on moding the least. The transmissions in the rsx were not mean to hold powers over the 300 to 350 range, 400 really pushes the trannies to their limits. Because of this you need to be prepared to do tranny work. Until recently there was no way except to do constant gear replacements. However, Bullhead gears recently came out with a gear set they say is strong enough to hold up to the pressures demanded by a boosted rsx. The best person to speak with on the forums is fade2black. He can also be reached at the crsx store. He has rebuilt enough transmissions that he could probably do it in his sleep. If you have any questions you would get the best results by directing your questions to him

Bullhead Gears
As I stated above the only recourse we had was to do yearly gear rebuilds on our transmissions. However, clubrsx has introduced Bullhead Gears. They were the first to use these gears, that are imported all the way from Australia. If you want more information on the bullhead gears please visit the two links below, or you may contact fade2black as he tested them personally.

Transmission Rebuilds and work
If you do end up needing transmission work done you might consider having clubrsx do they work. They do a very good job, and have tons of experience working on rsx transmissions. They are also very well priced. If you have any questions just visit here for more information.

Limited Slip Differentials
One of the important aspects of boosting a car is dealing with how to get the power to the ground. One problem you will face is that with the stock differential you will often spin out of control if you just try to punch it, especially in a lower gear. One way to prevent this is to swap out the stock differential with a limited slip differential. Again this work can be done through the clubrsx store if you wish and they even sell the lsd’s. Just contact fade2black for more information.

Clutches are a very important part of the build. You don't really have a choice to upgrade the clutch. If you leave the stock clutch in it won't last very long at all. Based on what horsepower level you want determines what clutch you should go with. The most common clutch upgrades go with either stage 3 or stage 4. For the really high horsepower applications you can go with the twin disc clutches, but those put a lot of stress on the transmission. Visit the store for more informaiton. Clubrsx Store - Clutch Section

One thing most people upgrade as well is the flywheel. The stock flywheel is very bulky and heavy. Most people opt to go with a lighter flywheel. This will give you smoother shifting and help with your shifting time, which is important when racing. Notice i said help with your shifting time. The shifting time is still mostly affected by the capabilities and expierences of the driver.

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ECU Management

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Perhaps the most important investment you will make outside of the turbo and manifold it’s self is the ecu management. For our cars there is no competition, Hondata is absolutely the best for ecu management software. However, they come at a price. You may see threads about others like AEM or Emanage. While AEM has it’s advantages it doesn’t hold a candle to Hondata. But as far as emanage goes don’t waste your money. If you are stupid enough to buy emanage, or crazy enough to buy AEM please don’t worry about posting because you will just be :laughat: relentlessly. The best thing for you to do is to invest in Hondata Kpro. Kpro gives you the ability to modify you ecu setting. This is what is done when you get a tune done. If you don’t get a ecu management system you car will suck and not perform as you want. If you have any questions about kpro just ask them in the chat thread. However most other ecu questions should be directed at the ECU and Tuning Forum. One thing to consider before you purchase KPRO. Kpro is different for the 05+ Rsx because it requires a new Adapter Harness. Also below is a Kpro Instructional DVD, the DVD is very good for learning the basic and history of KPRO


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Engine Rebuilds

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One of the most important things to decide is to choose if you are going to upgrade your motor internals. The stock rsx has been show to hold 350 whp without much problems. However anything about that you take a lot of risk of damaging or destroying your motor. Just take a qucik brouse through the turbo forum and most likely you will find quite a few "Help: I blew my motor" threads. Engine Rebuilds are the most work intestive parts of the build process. The most important thing to understand about the rebuild stage is compression ratios. The stock rsx has 11.0:1 compression ratios. This ratio is good for naturally aspirated motors, but with a boosted car you want to go with a lower compression in order to prevent premeature detoniation (aka knock). Knock happens when the gases inside the motor explode on thier own, without a spark from the spark plug. This happens because the air and gas are compressed to the point where they spontaneously combuste. Most turbo cars run a 9:1 to 10:1 ratios. The lower the compression ratio the more you can advance the fuel and ignition tables (which are what give you power). However, the draw back is that the lower the compression the less exhaust gases you have, so the longer it takes to spool your turbo. It's all a matter of give and take.

Compression ratio with boost

Before discussing compression ratio and boost, it is important to understand engine knock, also known as detonation. Knock is a dangerous condition caused by uncontrolled combustion of the air/fuel mixture. This abnormal combustion causes rapid spikes in cylinder pressure which can result in engine damage.

Three primary factors that influence engine knock are:

Knock resistance characteristics (knock limit) of the engine: Since every engine is vastly different when it comes to knock resistance, there is no single answer to "how much." Design features such as combustion chamber geometry, spark plug location, bore size and compression ratio all affect the knock characteristics of an engine.

Ambient air conditions: For the turbocharger application, both ambient air conditions and engine inlet conditions affect maximum boost. Hot air and high cylinder pressure increases the tendency of an engine to knock. When an engine is boosted, the intake air temperature increases, thus increasing the tendency to knock. Charge air cooling (e.g. an intercooler) addresses this concern by cooling the compressed air produced by the turbocharger

Octane rating of the fuel being used: octane is a measure of a fuel's ability to resist knock. The octane rating for pump gas ranges from 85 to 94, while racing fuel would be well above 100. The higher the octane rating of the fuel, the more resistant to knock. Since knock can be damaging to an engine, it is important to use fuel of sufficient octane for the application. Generally speaking, the more boost run, the higher the octane requirement.
This cannot be overstated: engine calibration of fuel and spark plays an enormous role in dictating knock behavior of an engine.

Compression ratio is defined as:

CompressionRatio = Displacement Volume + Clearance Volume
Clearance Volume​

CR = Vd + Vcw

CR = compression ratio
Vd = displacement volume
Vcv = clearance volume

The compression ratio from the factory will be different for naturally aspirated engines and boosted engines. For example, a stock Honda S2000 has a compression ratio of 11.1:1, whereas a turbocharged Subaru Impreza WRX has a compression ratio of 8.0:1.

There are numerous factors that affect the maximum allowable compression ratio. There is no single correct answer for every application. Generally, compression ratio should be set as high as feasible without encountering detonation at the maximum load condition. Compression ratio that is too low will result in an engine that is a bit sluggish in off-boost operation. However, if it is too high this can lead to serious knock-related engine problems.

Factors that influence the compression ratio include: fuel anti-knock properties (octane rating), boost pressure, intake air temperature, combustion chamber design, ignition timing, valve events, and exhaust backpressure. Many modern normally-aspirated engines have well-designed combustion chambers that, with appropriate tuning, will allow modest boost levels with no change to compression ratio. For higher power targets with more boost , compression ratio should be adjusted to compensate.

There are a handful of ways to reduce compression ratio, some better than others. Least desirable is adding a spacer between the block and the head. These spacers reduce the amount a "quench" designed into an engine's combustion chambers, and can alter cam timing as well. Spacers are, however, relatively simple and inexpensive.

A better option, if more expensive and time-consuming to install, is to use lower-compression pistons. These will have no adverse effects on cam timing or the head's ability to seal, and allow proper quench regions in the combustion chambers.

Now if you decide to upgrade your motor these are the things you will need to consider.

1. Will you be doing the work yourself? This is important to decide cause engine work is very expensive and time consuiming. Just know that if you decide to work on it go ahead and make a budget and time line. Then multiply the budget by at least too, and the timeline by at least 3 in order to get realistic goals. I know that may be hard to believe but believe me ask anyone on the board **** happens. To explain this here are some of the things that you will have to consider.

Tapping the Oil Pan
One of the ways the the bearing says lubricated is by running oil through it. You have a feed line which comes off of the engine block, and then is drained from the turbo back to the oil pan so the oil can be reciruculated.

Crank Bearings & Polishing
One thing that needs to be check carefully is the crank. Due to problems with the crank no being 100% balanced or knock the rod ends can wear unevenly on the crank. Because of this the crank may need to be polished. Don't take this to lightly. Even the best of the best (aka fade2black) had taken to much off of a crank and had a couple grand paper weight. Even if you don't polish the crank you will need to determine what bearing to get for the crank. Anytime you do engine work it's a good idea to replace the bearings. To replace them you will have to look at the color code that corresponds to the bearings and to the crank journal. To do this will require alot of thinking and preperation

First you need to get the bearing codes off the block. These are the Crank Bore Codes

Now you need to get the codes off of the crnak it's self. These are the Main Journal Codes

Now that you have the two codes you can use the chart below to determine what bearing to go with.

2. Rods & Rod Bearings
This is the most important upgrade of the engine build. If any part of the engine gives it's most likely gonna be the rods. And when a rod goes it will destroy your engine. I saw a rod punch a hole in a block where i could put my fist through. I went with manly rods, and everyone has thier own opinion about what rods to go with. You can see all the rods ther store sells here at Crsx - Engine:Rods

I am going to post some more information later about Rod Bearings. I have some pictures but I currently over the limit of 10 pictures per post so I will have to talk to a mod or admin about changing that for this post. In the mean time if you have any question just visit the chat thread.

3. Piston and Piston Rings
Of course one of the most important upgrades is the Piston and Piston rings. Even if you don't upgrade the piston you need to always upgrade the piston rings. As the piston rings wear down they they can damage the piston walls. This is what causes the uneven wear on the cylinder walls we will talk about later. The rings are very difficult to install, and they are easy to break, so be extra careful when installing the rings, and making sure that none of the gaps in the rings line up. So there are a couple of things you need to consider when choosing a pistions

The Compression ratio
You need to choose what compression ratio you want to go with. Again this depends on what your goals are. Most boosted apps stay between 9:1 and 10:1. If you want more information on this just ask.

Piston Size
This is a very hard thing to calculate. The stock piston size is 86mm. However, if you polish the cylinder walls or bore them out you will need to use a digital caliper to measure the diamaeter of the clyinder wall. Because every engine is different there is no standard here, and it's up to you to determine what you need. If you need more help just hit one of us up in the chat threads.

For more information or purchasing infromation just visit the store at CRSX Store - Engine Pistions Section

4. Sleeve and cylinder Walls
One week point in engines is the cylinder walls. It's hard to understand unless you look at what the cylinder walls undergo. If you look at the stresses enduced by the combustion cycle you will get a better understanding of how it affects the cylinder walls.

Intake. During the intake stroke, the piston moves downward, drawing a fresh charge of vaporized fuel/air mixture. The illustrated engine features a 'poppet' intake valve which is drawn open by the vacuum produced by the intake stroke. Some early engines worked this way, however most modern engines incorporate an extra cam/lifter arrangement as seen on the exhaust valve. The exhaust valve is held shut by a spring

Compression. As the piston rises the poppet valve is forced shut by the increased cylinder pressure. Flywheel momentum drives the piston upward, compressing the fuel/air mixture.

Power. At the top of the compression stroke the spark plug fires, igniting the compressed fuel. As the fuel burns it expands, driving the piston downward.

Exhaust. At the bottom of the power stroke, the exhaust valve is opened by the cam/lifter mechanism. The upward stroke of the piston drives the exhausted fuel out of the cylinder.

Inorder to combat the huge stress's that are a part of the combustion cycle, we put sleeves around the cylinder walls to help with the pressure. You can look at the store for sleeve pricing. You will also need to contact a shop to push the sleeve in. If you are intrested clubrsx can do it. Contact fade2black for pricing information.

5. Headgasket
There are some debates as to if aftermarket headgaskets are worth the money. I will leave the decision up to you, but i will say this. I use a stock OEM headgasket. There are two things to consider when thinking about headgasket. You can get a thinner or thicker headgasket. What you need to know is that with a thicker headgasket you lower the compression, and with a thinner headgasket you help to raise the compression. It doesn't affect it to much but it does have some affect on the cr. Just keep that in mind when choosing a headgasket.

6. HeadWork
Head work is not as important as other modifications but it is still important to consider. Head work usually involves cleaning of the head, and potential replacement of valves, springs, and retainers. If you have any questions just ask in the chat thread or contact the clubrsx store.

This is by now means a complete list it's a very simplified overview of what needs to be done but hopefully it will help you in deciding how you want to approch handling your engine rebuild.
Well.. since my stuff never gets sticky!! And this has some great information I will add my stuff to this thread.

What is a fuel systems job?

A fuel systems job is mainly to maintain a proper fuel demand throughout the system that will eventually be sprayed from the fuel injectors into the intake stream and into the combustion chamber.

What does a Fuel System Consist Of?

This depends on if it is a return or return-less fuel system. If it is a return fuel system, it has a fuel tank, fuel pump, sending fuel lines (from the pump to the fuel rail), a fuel rail, fuel injectors, fuel pressure regulator and returning fuel lines to the fuel tank. If it is a return-less fuel system, it has the same items but no fuel pressure regulator and return fuel lines.

How does a return fuel system work?

A return fuel system first starts out in the fuel tank. Everyone knows you go to the gas pump and put fuel into your gas tank, so that’s where it originates. Typically, the fuel pump is located inside the fuel tank. The fuel pump sends the fuel from inside the fuel tank through the fuel lines (sending lines). This fuel being sent is sending a high pressure to the fuel rail. As it enters the rail, fuel tries to either be sent back to the fuel tank or into the fuel injectors themselves. What keeps all the fuel from going back to the fuel tank? The fuel pressure regulator. The fuel pressure regulator will determine the amount of fuel being returned or staying inside the fuel rail. Also, by restricting the fuel line, it’s increasing the pressure inside the rail which effects the amount of pressure inside the fuel injectors and how much fuel is being sprayed out during the injectors cycle. After this, fuel that is not being used is now sent back to the fuel tank via fuel return lines (which were attached to the fuel pressure regulator). Fuel returns to the fuel tank and the cycle of fuel starts all over.

How does a return-less fuel system work?

Very similarly to a return fuel system except fuel is not sent back to the fuel tank if it’s not being used, hence, it doesn’t have an fuel pressure regulator to “regulate” fuel being sent back to the fuel tank. There are a couple of ways that fuel is maintained. On a return fuel system, fuel being sent from the fuel pump is sent at a constant rate, on some fuel systems, the fuel pump fluctuates depending on the voltage sent to the fuel pump from the computer. The computer decides when more fuel should be sent and it also determines when there should be less fuel sent. Other return-less fuel systems have a valve inside the fuel pump itself that can change the flow rate of the fuel pump.

What is every items job specifically?

1. Fuel Tank – To store fuel a certain capacity of fuel (gasoline)
2. Fuel Pump – To send the fuel towards the fuel rail via fuel lines (sending lines)
3. Sending Fuel Lines – To carry the fuel that was sent from the fuel pump to the fuel rail
4. Fuel Rail – Fuel rail is the central area where fuel comes to from the fuel sending fuel lines. The fuel that ends up here either gets pressurized into the fuel injectors or (on a return fuel system) gets sent back to the fuel tank.
5. Fuel Injectors – Fuel injectors job is to open and close at certain times on a 4 stroke engine (during the intake stroke). As it opens, it sprays fuel into the air intake stream which will get carried into the combustion chamber. Throughout the rest of the strokes, it remains closed.
6. Fuel Pressure Regulator – It is a device that is on the end of your fuel rail. On most units, there is a vacuum reference line that is connected to the intake manifold. As vacuum pressure drops (nearing towards atmospheric pressure), a spring inside the fuel pressure regulator tightens against a diaphragm which will start to restrict fuel from returning to the fuel tank. As it restricts fuel, it is also raising the pressure inside the fuel rail. Fuel pressure rises and drops according to the vehicles condition, whether it would be idle, cruising or wide open throttle. This item is only found on return fuel systems, NOT return-less fuel systems.
7. Fuel Return Lines – Carries fuel back to the fuel tank which the cycle of fuel starts over again. Once again, this item is only found on return fuel systems, NOT return-less fuel systems.

When should I change my fuel injectors?

You only change your fuel injectors when they are starting to exceed a certain duty cycle. The industry standard is 80% - 85% duty cycle maximum that a fuel injector should flow. Anything higher, you run the risk of overheating from the kinetic energy that they produce which will cause them to not open/close efficiently or just plain failure.

What is duty cycle?

Duty cycle is referring to the time that an fuel injector is open divided by the time that it can possibly be open during two complete engine revolutions.

Ok, I want to build up my car but I’m not sure what size fuel injectors to get. How do I find out what size I need?

This is a very common question asked. First, understand the point of changing your injectors is to maintain a certain demand of fuel to your engine from your fuel system as efficiently and reliably as possible.

When shopping for fuel injectors, understand that fuel injectors are also rated by fuel pressure. Fuel is being sent as high amounts of pressure which are typically measured by PSI. Lets use for example, you find fuel injectors that are 42 lbs/hr rated at 40 PSI of fuel pressure. Your car might run it’s highest at 50 PSI of fuel pressure. If you were to put these 42 lbs/hr injectors are going to be spraying more lbs/hr than the original rating just because of the increase in fuel pressure on your vehicle compared to their original rating. This might or might not what you would be aiming for depending on what you’re using to control the injectors throughout idle, cruising speeds and wide open throttle but this is what you would have to shop for.

NOTE: Industry standard for fuel injector rating is about 45 PSI of fuel pressure (3 BAR of fuel pressure)

Now, what size do you need? There is a very good calculation that you can use to give yourself a good accurate answer:

Flow Rate = (Horsepower x BSFC) / (# of Injectors x Max Duty Cycle)

Ok, you’re probably thinking “what the hell is BSFC?”. BSFC stands for brake-specific fuel consumption which are rated in pounds per hour. The average for naturally aspirated engines is about 0.45 and for turbocharged engines about 0.55 at full throttle (It could normally be anywhere from 0.4 to 0.6). Like said, these are estimations but it will give you a good idea.

Lets use an example:

Say you have a Honda Civic 2.0 and you’re looking to turbo-charge it but you want to know the proper size injectors to get. Your goal is 300 Horsepower (flywheel horsepower). It’s a 4 cylinder engine, so it has 4 injectors and the max duty cycle I’m looking to ever go to is 80%. So lets do the math…

Flow Rate = (300 HP x 0.55) / (4 x .80)
Flow Rate = (165) / (3.2)
Flow Rate = 51.5625

So I just figured out that if I wanted an estimate of 300 flywheel horsepower and don’t want to exceed 80% duty cycle, I would need fuel injectors that are about 51.5 lbs/hr and this is also understanding 51.5 lbs/hr at whatever given rating of the fuel pressure.

What is the difference between low and high impedance injectors?

The amount of voltage an injector needs to open. High impedance basically means it needs a higher amount of voltage sent to the injector to have it open fully and properly. Lower impedance injectors are just vice versa. High impedance injectors as far as voltage go need anywhere up to 12 Ohms, low impedance are around 3-5 ohms but of course, this depends on the vehicle and engine management system.

Do I need to upgrade my fuel system if I run a nitrous kit? (wet or dry kits)

Not to get too off topic but a brief description of how each kit works and why you would or wouldn’t need to upgrade with either one. I am assuming that you already know how nitrous affects an engine as well:

A wet nitrous kit basically means that as nitrous is being injected into your air intake stream it is also spraying fuel to keep a well balanced air fuel ratio inside your combustion chamber. Depending on how this kit is installed and the vehicle you’re using, you can either tap into the fuel line or the fuel rail for a source of fuel.

Do you need to upgrade your fuel system on a wet kit? Depends. Your fuel injectors, no you don’t need to upgrade them because the fuel that you are supplying along with the nitrous is coming from an outside source and not being sprayed through your fuel injectors. Your fuel pump, maybe. Depending on the stress that is made on the fuel pump to keep a certain demand of fuel (GPH), it might need to be to keep from starving the fuel injectors as well as keeping your “wet line” supplied with enough fuel.

Do you need to upgrade your fuel system on a dry kit? Yes (or at least I suggest it). With a dry kit, you’re just spraying nitrous alone and now you’re taking the fuel management side into your own hands by relying on your fuel system for fuel supply during nitrous injection. Same rules apply as far as overworking your injectors or fuel pump. It’s all about maintaining a proper fuel supply and demand. When things are off balanced and over looked, bad things will start to happen which typically results in lean air/fuel mixtures if it’s not adequate enough during a dry shot injection.

Some cars have return-less fuel systems and some have return fuel systems. Why is it like this? What’s better for performance?

Return-less fuel systems were created, for one, help the computer control more of the amount of fuel being sent to the fuel rail and to also reduce on the likeliness of fuel leaks by reducing the amount of lines used.

What’s better for performance? Return fuel systems are. They are better for performance in the aspect that all fuel that is entering the rail is entering the fuel injectors at an about equal rate and they are getting an about equal amount of fuel. What typically happens with return-less fuel systems is that as fuel is coming in from one side of the fuel rail, it might be starving the farther injector(s), so they aren’t getting sufficient amount of fuel into the injector(s), hence, not supplying the proper amount of fuel into the combustion chamber which could result in lean mixtures that cause detonation & possible engine damage. Now, this is of course speaking from a high performance point of view and not necessarily in a stock or near stock situation.

What are rising-rate fuel pressure regulators?

Rising rate fuel pressure regulators basically do the same job as your stock (OEM) fuel pressure regulator. Your stock fuel pressure regulator raises fuel pressure as vacuum pressure drops. It has a line that connects from the fuel pressure regulator to the intake manifold to read the air pressure inside the manifold, which helps determine the desirable fuel pressure inside the fuel rail.

On an OEM unit for a naturally aspirated engine, if you were to turbo-charge the engine, as you’re increasing above atmospheric pressure (boost pressure), it will rail fuel pressure inside the fuel rail on a 1:1 ratio (for every pound of boost, it will raise the fuel pressure 1 PSI inside the fuel rail).

On an rising rate fuel pressure regulator, depending on the unit, it will raise the fuel pressure higher than the OEM 1:1. It can be anywhere from 6:1 to 12:1 ratio of fuel pressure to boost pressure.

Increasing fuel pressure will also increase the amount of fuel going through the fuel injector every time it opens but also understand that too much fuel pressure on an underrated fuel injector can cause that fuel injector to not operate properly from internal damage. Another thing to look out for is your fuel pump (which will be explained) as it is also rated to send a certain amount of fuel to your fuel rail. As you’re increasing pressure by restricting the amount of fuel returning to the fuel pump, you’re also slowing down the amount & speed of the fuel to travel from the pump to the fuel rail. Basically, as you’re increasing pressure, you’re also decreasing the rating on the fuel pump.

I want to get a new High Flowing Fuel Pump, which one should I get?

Once again, changing the fuel pump is to keep up with the demand of the rest of the fuel system. Your fuel pump is rated typically either by lbs per hour or gallons per hour.

As you shop for a fuel pump, you will run into different descriptions of the fuel pump, which will refer to: Capacity (lbs/hr or gph), Voltage & Fuel Pressure (PSI). The fuel pressure part is referring to the amount of fuel pressure that in the fuel system that your fuel pump has to constantly supply towards.

The equation to figure out what fuel pump you would need is as follows:

Flow Rate = Horsepower x BSFC
Flow Rate = X lbs/hr

So lets use an example:

Say you have your, once again, Honda Civic 2.0. Your goal is 300 Flywheel Horsepower with a turbo-charger, you’re assuming 0.55 BSFC, and your constant fuel pressure is 50 PSI.

Flow Rate = 300 x 0.55
Flow Rate = 165 lbs/hr

Now, if your fuel pump you’re shopping for is rated in gallons per hour (GPH), then you take that number and divide it by 6. Your answer is 27.5 GPH.

What happens if I don’t provide enough fuel for my engine?
Your engine is basically meterd by a certain amount of air to fuel. You basically need air in order to burn fuel. If there isn’t enough fuel being supplied, this can cause it to run into what is called a lean condition. Lean conditions can cause improper combustions to knocking (detonation) and quite possibly engine damage depending on how bad the condition is.

Can I use fuel injectors from another car?

Yes. The most common fuel injector is the Bosch pintle type injector, if you’re able to find larger injectors that are the same style as your vehicles, you should be able to use those injectors.

If I wanted brand new injectors, what manufacturers can I buy from?

Bosch, Accel, RC Engineering for starters.

If I wanted to buy a new fuel pump, what manufacturers can I buy from?

MSD & Walbro are bigger name companies. You can check them out and see if they have a fuel pump that is rated for your application’s fuel system needs.

How do I convert flow rates? What’s the calculation?

To convert from CC/Min to Lbs/Hr

CC/MM = lbs/hr x 9.71

To convert from lbs/hr to cc/min

Lbs/hr = cc/min x .103

Gallons Per Minute = (lbs/hr) / 369.8

This illustration should give you the basis of a fuel return system.

A typical vapor return schematic diagram is shown below:

Note that the fuel return must go to the top of the tank above the surface of the fuel. If the return is positioned below the surface of the fuel, then the return line must include a one way check valve preventing unfiltered fuel from entering the TBI.

Thanks to PanamaSi2007 for the PICS!
What are the main differences between Superchargers and Turbochargers


There is almost no question that we get more than, “what are the main differences between Superchargers and Turbochargers, and which one do we recommend for each application. They both have obvious similarities, like the fact that both are air compressors, but what are the main differences between the two.

Very simply put, one of the biggest differences between a turbocharger and a supercharger is in what provides it with its power. There has to be a power source to run the air compressor. A supercharger has a belt that connects directly to the engine while a turbocharger receives its power from the exhaust stream.

But, more about that later, first lets talk about more of what both do. Both superchargers and turbochargers are forced induction systems and use compressors to increase the amount of air forced into the engine. One of the simplest ways to increase the horsepower of an engine is to increase the amount of air and fuel that it can burn. Normal engines will experience reduced power at high altitudes because for each stroke of the piston, the engine will receive a smaller amount of air. Both superchargers and turbochargers allow an engine to burn more air and fuel. By compressing more air into the cylinders this allows more fuel to be added. This creates more power from each explosion in the cylinder, in turn leading to more horsepower. The typical boost produced by these units is 6 to 10 pounds per square inch (psi). Normal atmospheric pressure is 14.7 psi at sea level, so you are getting about 40 to 50 percent more air into the engine. From this, you can expect around a 40 to 50 percent increase in horsepower.

The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which in turn spins a compressor forcing air into the cylinders. The turbine is connected to the compressor by a shaft. The compressor pressurizes the air going into the cylinders. The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin. On the opposite end of the shaft that the turbine is attached to, a compressor pumps air into the cylinders. The compressor is a type of centrifugal pump in which it draws air in at the center of its blades and forces it outward as it spins.

In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power supply. This means more overall power from the same amount of boost. Another advantage to turbochargers is the incredible number of units available. This means the size of the turbo can be easily matched to the demands of the engine. This can allow instant boost, and peak levels over thirty pounds of boost.

On the other hand, a turbocharger causes some amount of backpressure in the exhaust system and tends to not create immediate boost when you accelerate. It takes a second or two for the turbine to spool up before boost is produced. This results in a feeling of lag when you accelerate, and then the car lunges ahead when the turbo spools up. This surge cannot only be damaging to the engine, but it can create loss of traction and a loss of drivability. A supercharger is connected directly to the crank pulley, so you are able to produce boost without the lag time. The root and screw type superchargers are able to create boost at an even lower rpm range. The supercharger does not create backpressure because it has no interference with the exhaust system.

The supercharger is bolted directly to the intake manifold or on the side of the engine by the means of a bracket. The supercharger drive pulley is attached to the internal impeller by a shaft. The drive pulley is attached to the engines crank pulley via a belt. As you increase the rpm’s of the motor, the supercharger’s internal impeller spins faster. This allows the supercharger to compress air inside of its casing before it forces it into the engines air intake. The speed at which the impeller spins, determines how much boost can be produced. Changing the drive pulley is a simple way to increase or decrease your boost.

Superchargers are far easier to install and maintain than a turbo because they have fewer parts. A turbo requires far more engine modifications and have a greater number of parts than a supercharger making them far more difficult to install and tune.

One can determine that both turbochargers and superchargers are a simple way to create large amounts of horsepower through a single part. Superchargers on average tend to better suited for the average driver, however turbochargers will always remain a favorite for those guys that desire insane amounts of boost.

Cost is relative between a supercharger and turbo chargers. Both versions have their kits that range from $3000-6000 dollars depending on Brand name and WHP output. Have to make the determination to which will fit your need.

Tuning has been the issue in the past and present but the future looks better. Hondata, AEM and Haltech are bringing newer technology in the coming months that will give broader range of tuning.

Hope this helps. Do a search and you can compare cost between S/C and Turbo kits on the market and relative information on total cost that can be excepted in the long haul. When boosting or N/A just remember things will break so remember to have extra $$$ around for repairs.
Boost Spike vs. Boost Creep


Since these two terms are very commonly used in describing turbo/engine behavior, yet they are not always understood correctly, I wanted to attempt to clear them up.

People often mix the two up, or even interchange them, when they are in fact two VERY different things.

Boost Spike: Boost spike is when the boost level initially "spikes" up to higher than the preset boost setting, and then quickly settles back down to where it should be. As most people with turbos know, once the boost pressure in the intake starts to rise, the rate at which it rises quickly increases until the pressure is increasing at a phenomenal rate. This means that, if your boost is set at 12 psi, when it reaches that point it will be increasing so quickly that it will go higher than 12 psi and then drop back down once the boost control system can correct it, which is within a half second or so.

Some causes of spike are bad boost controllers (only ball-and spring type MBC's should be used, and only proven electronic boost controllers should be used), long boost source or wastegate activation hoses, and the lack of any boost controller at all. It's basicially an effect a t slow response time of the boost control system.

Boost Creep: While boost creep also refers to an unwanted rise in manifold pressure, its cause and effect are totally different from those of spike, as is the way it manifests itself.

As you know, boost pressure is controlled by the wastegate, which allows exhaust gasses to bypass the turbine wheel. In effect, it creates an alternate route for the hot exhaust coming out of the motor to take, which means that any gas passing through it will not spin the turbine wheel.

Now, if this wastegate cannot flow enough to bypass the required amount of exhaust, then that means that too much of the gasses are going to go through the turbine wheel, meaning that it will have too much energy imparted on it (it will be spinning too fast). As the excess exhaust gas amount gets greater and greater, the turbine wheel spins faster and faster, and the boost level rises.

Creep happens ANY time when the wastegate cannot bypass enough exhaust gas to keep the boost under control. This can happen when the wastegate is too small in diameter, or when the design of the wastegate doesn't allow it to open enough, or when the wastegate simply doesn't have a good enough flow path to divert a lot of exhaust. It can also happen when you increase the amount of exhaust coming out of a motor (running more boost/airflow, making more power).

Since this tends to get worse and worse as the engine speed rises (more cycles per second is more conducive to more exhaust gas, to a point), that means that one will see the boost climb to the preset level on the boost controller, and then it will gradually creep up past that line to a "minimum" given the circumstances.

That minimum can be 2 psi above the set boost level, or it can be over 30 psi, depending on how the wastegate is designed, how big it is, the car's setup, and more.

It is also important to not that you certainly can have spike AND creep at the same time, which would result in the boost level jumping up, settling to the preset level, and then slowly climbing back up again as you approach redline.

8,668 Posts
Bad ass post even though you didn't write it. I got a lot of reading ahead of me. One thing I saw that didn't jive was the "stock RSX 350cc inj are good to 350 hp" I don't think so. But on the whole it looks good.

42,510 Posts
Discussion Starter · #6 ·
Bad ass post even though you didn't write it. I got a lot of reading ahead of me. One thing I saw that didn't jive was the "stock RSX 350cc inj are good to 350 hp" I don't think so. But on the whole it looks good.
You will get a lot of information out of this. As far as the stock injectors, it seems like they have tried it. Remember they have K-Pro, and that might allow them to use the stock injectors up to those numbers. Also, if I'm not mistaken the Greddy Kit for the RSX doesn't come with an intercooler, so who knows if they even supply injectors for that kit. On the Si, Greddy supplies 370cc Injectors, so who knows, I guess they can be pushed up to 350hp but I'm sure the duty cycle on them is close to being 100%

42,510 Posts
Discussion Starter · #13 ·
The RSX guys are getting some rediculous horespower numbers, are they building their internals or is that just because they have kpro?
With K-Pro, you are basically playing with the whole car so thanks to that they can get more power out of the engine without doing internals. Since we only have the E-Manage or any other piggybacks, which don't allow us to do full tuning, then we have to be really careful, thats why you only see a max of 300hp or so without doing internals.

As soon as you do internals, well, your possibilities are endless, but without a full standalone, it won't be as "reliable" as the RSX guys.

I've been reading and it seems some of them are pushing close to 450hp on a stock motor. Would I do it? No. Can the motor handle it? Seems like it can.

42,510 Posts
Discussion Starter · #18 · (Edited)
Here's a post about the NST Pulleys

Ouch, that sucks. But I can't say I didnt see that coming.

RE: Pulley discussion earlier in this thread.

I want to see one of these pulley's in person. I'm willing to bet that the edges don't have a .032 radius. Without at least a .015 radius on all edges harmonics will destroy a machined part. .032R would be best for all edges especially on something with such a broad harmonic range...hence the demise of the pulley.
Here's what I wrote in another thread regarding the TBS:

Regarding the NST pulley's, dump them. The benefits (or lack thereof) are not worth the cost of vibration/balancing.
The motor is not internally balanced. The rotational assembly is not balanced with in +/- .5g. The crank pulley is built in with a harmonic damper, and its 60% weight reduction reduces its harmonic reduction. This will cause runout in your mains.

4,552 Posts
wow thats alot of great info. most of it i knew cause its all about theory of how a tubo works but still awesome thread for reference and i learned some new things.

i like how most of the options they give for certain things the 300whp is at the low end lol. all i want is 300hp. even if k pro came out.
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