537
06-28-2004, 10:42 PM
Hi!
Once again I'm back to bring about awareness to the masses. In my previous article (Part II) (http://forums.yellowworld.org/showthread.php?t=16988), we briefly went over some items that can be checked off in order to improve upon a vehicle's maneuverability and driver comfort. We went over certain aspects of handling and how to negate some of their shortcomings, including braking and suspension. Today, we're going to cover the meat of the tuning industry. That's right, folks. We're going to focus on obtaining more power!
Before getting to the nitty gritty, I feel it necessary to conduct a crash course in gasoline engine dynamics and design. With that being said, let's get it started!
a. Combustion Engine Theory
For all intents and purposes, we will be focusing on gasoline combustion engines for this article.
All gasoline internal combustion engines rely on four things. Oxygen(air), Fuel, Compression, and Ignition. With the correct mixture of the above a controlled detonation results in a powerful source of energy used to conduct work. Straight from the factory, a vehicle is designed to stay environmentally friendly, yet offer adequate power. It is, in essence, the detonation that tuners attempt to modify, partially or completely stemming from changing the mixture of the above variables. The following sections will give a little more detail in this regard, appropriate to the type of engine it references.
b. Engine design
Gasoline Internal Combustion Engines (which this article will focus on because the majority of road/race vehicles are of this type!) can be roughly classified into two categories. Not surprisingly, there are differing schools of thought as to which is the better design. They are:
Conventional Piston
Rotary
Both types of engines rely on the four things indicated in Combustion Engine Theory, however approach that realization using different terms. For ease of use and for simplicity's sake, we will be approaching Stage I power modifications for these two engine types the same. It is not until you further desire more power that the avenues to do such take on different paths.
Outlined in the previous section was a term I referenced as the correct mixture of Oxygen, Fuel, Compression, and Ignition. One thing that is for sure is that automobile engineers have completed their due diligence and maintain this mixture for longevity and economical purposes. Once you modify this to deviate from OEM specifications, you can quickly deteriorate or worse yet, destroy an engine. An example of this disastrous condition would be increasing the amount of oxygen and not adding appropriate amounts of fuel to the mixture, therefore creating what is called a fuel lean condition. This generates additional heat, leads to premature detonation, and causes engine knock. This is the number one cause of melted pistons/broken rods/broken piston rings. For that reason alone, we'll be attempting to stay as true to the factory specified ratios of Air and Fuel as possible for these Stage I modifications.
If that didn't scare you into reading no further, that's great news! Nowadays, automobile engineers have also built into the vast majority of vehicles, something called a Mass Air Sensor (or air mass sensor/air density probe, etc.). This sensor takes active readings about the air such as air temperature, velocity, humidity, and altitude to determine how much oxygen the engine is about to see. This information is then sent to the vehicle's ECU where a decision is made about how much fuel is needed to create the proper air/fuel ratio. From that point, a signal is sent to the vehicle's fuel delivery system detailing how much gasoline its injectors shall inject into the cylinders, where that mass of air awaits the engine's compression cycle/stroke (physics buffs will note that combustion occurs much more easily and with more force while fuels/oxygen are pressurized). At the designated point of proper compression, the ECU then sends a signal to the engine's ignition coils to light a spark, igniting the pressurized mixture. The gases produced from the combustion are then expelled via an engines exhaust ports and eventually end up in the atmosphere via your vehicle's tailpipe. This contained explosion is the heart of all internal combustion engines, and is the singular driving force at work which ultimately propels your vehicle. Now this is an extremely high-level explanation of what goes on under your hood. But enough of this techno-babble, anyhow. Let's get on to what we're here for.
It is because of a vehicle's Mass Air Sensor (or its equivalents) that we are able to modify the amount of air the engine will 'breathe', yet maintain the proper air/fuel ratio required to keep everything in good working condition. Which leads us to....
c. Part III, Stage II modifications -- Improving Power!
Improving a vehicle's 'breathing' capability is the one thing that tuners look to first to create more horsepower (Turbos, superchargers, nitrous, etc are all related to this, but remember, we're taking baby steps here!). In the tuning world, initial improvements can be made without manually modifying fuel delivery, adding ignition power, or changing compression. An engine's breathing capability can be closely tied to three components, which are:
'Intake' (Air Intake)
'Header' (Exhaust Header)
'Exhaust' (Cat-back Exhaust)
The Intake is where air is drawn into the engine through an air cleaning element. Typically this air cleaner is housed inside a restrictive plastic housing which serves two purposes...to silence the sound of the engine as you step on the accelerator, as well as keep it isolated from the intense high temperatures that live under the hood. Performance can be freed by installing a high quality air cleaner that is less restrictive, as well as using proper tubing to relocate it away from the engine bay. Intake systems such as these can be referenced as 'Cold Air Intakes'. Be careful of those CAI systems that relocate the filter too close to the ground, as this can spell bad news if ever submerged in water (or any liquid for that matter). If your engine breathes in water, it will become hydrolocked and will, quite literally, drown. Quality CAI systems provide a type of bypass valve to prevent this situation. Look for a CARB EO number stating that it is legal to use on public highways.
The next step to freeing up an engine's breathing capability is by improving upon its exhaust header assembly. Now before you turbocharged drivers get your panties all up in a bunch, remember your exhaust manifold is also an exhaust header, but there's just so much you can do to that. We'll get to that in another article, shall we? Anyhow, installing a properly designed header will grant you even more breathing capability. Look for one that bolts directly up to the OEM catalytic converter if your vehicle is a street car, and look for one that completely replaces the catalytic converter if your vehicle is a race vehicle. Look for a CARB EO number stating that it is legal to use on public highways.
The last step in this installation is to install an aftermarket Exhaust system. More commonly known as a 'Cat-back', exhaust systems usually consist of a free flowing muffler, and piping to hook up to an OEM catalytic converter. Quality systems are lightweight, are engineered out of durable long lasting materials (of which the more expensive ones are constructed out of Magnesium or Titanium, or an alloy of both), and brag about boasting a throatier, deeper growl. Make no mistake, noise does NOT equate to power, so do your research carefully and search for a proper flowing system that will compliment your vehicle. Look for a CARB EO number stating that it is legal to use on public highways.
With these components explained, I do have to say that they work together in the equation, and installing just an intake or header or exhaust will most likely waste your time. If you are looking for any type of gain, the three components really need to be chosen carefully to work with each other.
That about does it for this article, please stay tuned for my next article which will look even further into creating more horsepower, as well as further improving handling and brakes!
Once again I'm back to bring about awareness to the masses. In my previous article (Part II) (http://forums.yellowworld.org/showthread.php?t=16988), we briefly went over some items that can be checked off in order to improve upon a vehicle's maneuverability and driver comfort. We went over certain aspects of handling and how to negate some of their shortcomings, including braking and suspension. Today, we're going to cover the meat of the tuning industry. That's right, folks. We're going to focus on obtaining more power!
Before getting to the nitty gritty, I feel it necessary to conduct a crash course in gasoline engine dynamics and design. With that being said, let's get it started!
a. Combustion Engine Theory
For all intents and purposes, we will be focusing on gasoline combustion engines for this article.
All gasoline internal combustion engines rely on four things. Oxygen(air), Fuel, Compression, and Ignition. With the correct mixture of the above a controlled detonation results in a powerful source of energy used to conduct work. Straight from the factory, a vehicle is designed to stay environmentally friendly, yet offer adequate power. It is, in essence, the detonation that tuners attempt to modify, partially or completely stemming from changing the mixture of the above variables. The following sections will give a little more detail in this regard, appropriate to the type of engine it references.
b. Engine design
Gasoline Internal Combustion Engines (which this article will focus on because the majority of road/race vehicles are of this type!) can be roughly classified into two categories. Not surprisingly, there are differing schools of thought as to which is the better design. They are:
Conventional Piston
Rotary
Both types of engines rely on the four things indicated in Combustion Engine Theory, however approach that realization using different terms. For ease of use and for simplicity's sake, we will be approaching Stage I power modifications for these two engine types the same. It is not until you further desire more power that the avenues to do such take on different paths.
Outlined in the previous section was a term I referenced as the correct mixture of Oxygen, Fuel, Compression, and Ignition. One thing that is for sure is that automobile engineers have completed their due diligence and maintain this mixture for longevity and economical purposes. Once you modify this to deviate from OEM specifications, you can quickly deteriorate or worse yet, destroy an engine. An example of this disastrous condition would be increasing the amount of oxygen and not adding appropriate amounts of fuel to the mixture, therefore creating what is called a fuel lean condition. This generates additional heat, leads to premature detonation, and causes engine knock. This is the number one cause of melted pistons/broken rods/broken piston rings. For that reason alone, we'll be attempting to stay as true to the factory specified ratios of Air and Fuel as possible for these Stage I modifications.
If that didn't scare you into reading no further, that's great news! Nowadays, automobile engineers have also built into the vast majority of vehicles, something called a Mass Air Sensor (or air mass sensor/air density probe, etc.). This sensor takes active readings about the air such as air temperature, velocity, humidity, and altitude to determine how much oxygen the engine is about to see. This information is then sent to the vehicle's ECU where a decision is made about how much fuel is needed to create the proper air/fuel ratio. From that point, a signal is sent to the vehicle's fuel delivery system detailing how much gasoline its injectors shall inject into the cylinders, where that mass of air awaits the engine's compression cycle/stroke (physics buffs will note that combustion occurs much more easily and with more force while fuels/oxygen are pressurized). At the designated point of proper compression, the ECU then sends a signal to the engine's ignition coils to light a spark, igniting the pressurized mixture. The gases produced from the combustion are then expelled via an engines exhaust ports and eventually end up in the atmosphere via your vehicle's tailpipe. This contained explosion is the heart of all internal combustion engines, and is the singular driving force at work which ultimately propels your vehicle. Now this is an extremely high-level explanation of what goes on under your hood. But enough of this techno-babble, anyhow. Let's get on to what we're here for.
It is because of a vehicle's Mass Air Sensor (or its equivalents) that we are able to modify the amount of air the engine will 'breathe', yet maintain the proper air/fuel ratio required to keep everything in good working condition. Which leads us to....
c. Part III, Stage II modifications -- Improving Power!
Improving a vehicle's 'breathing' capability is the one thing that tuners look to first to create more horsepower (Turbos, superchargers, nitrous, etc are all related to this, but remember, we're taking baby steps here!). In the tuning world, initial improvements can be made without manually modifying fuel delivery, adding ignition power, or changing compression. An engine's breathing capability can be closely tied to three components, which are:
'Intake' (Air Intake)
'Header' (Exhaust Header)
'Exhaust' (Cat-back Exhaust)
The Intake is where air is drawn into the engine through an air cleaning element. Typically this air cleaner is housed inside a restrictive plastic housing which serves two purposes...to silence the sound of the engine as you step on the accelerator, as well as keep it isolated from the intense high temperatures that live under the hood. Performance can be freed by installing a high quality air cleaner that is less restrictive, as well as using proper tubing to relocate it away from the engine bay. Intake systems such as these can be referenced as 'Cold Air Intakes'. Be careful of those CAI systems that relocate the filter too close to the ground, as this can spell bad news if ever submerged in water (or any liquid for that matter). If your engine breathes in water, it will become hydrolocked and will, quite literally, drown. Quality CAI systems provide a type of bypass valve to prevent this situation. Look for a CARB EO number stating that it is legal to use on public highways.
The next step to freeing up an engine's breathing capability is by improving upon its exhaust header assembly. Now before you turbocharged drivers get your panties all up in a bunch, remember your exhaust manifold is also an exhaust header, but there's just so much you can do to that. We'll get to that in another article, shall we? Anyhow, installing a properly designed header will grant you even more breathing capability. Look for one that bolts directly up to the OEM catalytic converter if your vehicle is a street car, and look for one that completely replaces the catalytic converter if your vehicle is a race vehicle. Look for a CARB EO number stating that it is legal to use on public highways.
The last step in this installation is to install an aftermarket Exhaust system. More commonly known as a 'Cat-back', exhaust systems usually consist of a free flowing muffler, and piping to hook up to an OEM catalytic converter. Quality systems are lightweight, are engineered out of durable long lasting materials (of which the more expensive ones are constructed out of Magnesium or Titanium, or an alloy of both), and brag about boasting a throatier, deeper growl. Make no mistake, noise does NOT equate to power, so do your research carefully and search for a proper flowing system that will compliment your vehicle. Look for a CARB EO number stating that it is legal to use on public highways.
With these components explained, I do have to say that they work together in the equation, and installing just an intake or header or exhaust will most likely waste your time. If you are looking for any type of gain, the three components really need to be chosen carefully to work with each other.
That about does it for this article, please stay tuned for my next article which will look even further into creating more horsepower, as well as further improving handling and brakes!