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Discussion Starter #1 (Edited)
Technical Glossary (Formerly Basic Definitions for Performance Parts)

I need to change that title because it's not working for me...but we'll deal with that later.

I've noticed that we have some members on this board that are relatively new to the entire car modification thing but that may be thinking about upgrading their Sky with aftermarket performance parts. As such, I decided to try and put together a short list of different performance parts, what they do, and why people change them. I sincerely hope that those on this forum that know FAR more about automobiles will chime in here with corrections or additions to this "dictionary".

First, understand that an engine is nothing more than an air pump. As with any pump, the more you can get in and the more you can get out per pump the better (in our case faster). Every modification you do to an engine has to do with getting more air in or out of the engine and the upgrades necessary to use that extra flow.

Secondly, understand the difference between Wheel Horse Power (WHP or RWHP for Rear Wheel Horse Power) and Crank Horse Power (CHP). Our Sky's produce 177 CHP but because this power is then sent off to the transmission, drive shaft, differential and tires the actual amount of horsepower you see hitting the ground is usually less. Generally speaking, 20% of your CHP is lost by the time it hits the wheels. Most of our cars have been seeing 140-145 WHP. As such, a gain of 4 hp at the wheels will be about 5 hp at the crank.

Also keep in mind that horsepower gains ARE NOT accumulative. In other words, if you add an intake that will give you 10 hp and an exhaust that will give you 10 hp you will not have added 20 hp by doing both. You may see something like 15 hp but not 20.

Per CyaL8r's suggestion I do want to add something else in here. When adding power to your car you also want to add control. Bolting on another 100 horsepower without addressing important subsystems like brakes, suspension, and tires is foolish especially in a RWD Car as too much power can get you in trouble real quick. Remember to address things that will help you stop and control the car with that added power. As we get information on what products will do that as well as the whys/hows I'll post it.

Definitions:

60 foot - This term is a drag racing term and is the time it takes a car to go through the first 60 feet of the drag strip. The reason this time is important is based on the 60 foot time you can tell how well the car was launched. For instance, for the Pontiac Grand Prix, a FWD FI V6, on street tires a 60 foot of 2.0XX seconds is very good. However, a 60 foot of 2.2XX seconds will tell the driver he had a little bit of wheelspin. A 60 foot of 2.5XX or more tells him he had a LOT of wheelspin. Generally speaking, for every tenth (0.1) of a second you take off your 60 foot you will take two tenths (0.2) off your ET (see below). So a car that runs a 13.7 1/4 mile with a 2.2 60 foot could run a 13.3 with a 2.0 60 foot. However, it is also generally considered that the lower your 60 foot time (and consequently your ET) the slower your trap speed will be too.

Aftermarket Exhaust or Cat Back Exhaust - Stock exhausts are designed to meet the basic needs of getting the exhaust from the engine out of the vehicle without gassing the occupants while reducing exhaust noise. The factory exhaust is built with a speedy production run in mind. As such, shortcuts are taken to speed production at the expense of making an exhaust that is somewhat restrictive. After market exhausts are designed to free up these restrictions to provide more flow and thus more power. In addition, aftermarket exhausts are also designed to change the tone of the exhaust noise to give a meaner and/or louder exhaust note. Normally these systems are referred to Cat Back Exhaust systems because they attach to the car's stock catalytic converter and replace all the exhaust components from the "cat" on back. Hence Cat Back. Manufacturers will also use better materials such as stainless steel and/or nice chrome tips to reduce corrosion and improve appearance. Choosing a cat back is like picking out a new pair of shoes. So long as they fit the car "better" is only determined by the customer's personal preference. Expect a 5-10 WHP gain from an exhaust.

All Wheel Drive (AWD) - A vehicle with AWD has power going to all four wheels. This is different from 4-wheel drive in that it is constantly engaged and used not for off road travel but additional traction on paved surfaces or poor road conditions such as snow and rain. Generally speaking AWD vehicles tend to be more neutral in their handling but can experiance both understeer and oversteer.

Burn Out Box (AKA Water Box) - Drag racing term. Before you reach the staging area of a drag strip there is an area of concrete that the starters will water down. This is the Burn Out or Water box. Racers running Drag Radials or Slick tires will put their drive wheels in this water box so they can easily get their wheels spinning to warm them up before their run. Cars running street tires need to drive around the box as the treads of a street tire will hold water and spread it on the starting line area of the track (which is a bad thing).

Cam Shafts - Or just Cams. Cams control when, how long and how high your valves will open and close. The higher they open (lift) and the longer they stay open (duration) the more fuel you'll get in the car or the more exhaust you'll get out...depending on which valve you're looking at. However, too much lift or duration can cause engine damage so it is a fine line as to how much you increase these parameters. Also, valve float if you have too weak of a valve spring, can also damage your engine. We have two cams in our Ecotecs that, currently, are not offered on the aftermarket. However, changing your cam is a way to see some pretty impressive power gains.

CARB Certified - CARB (Clean Air Resources Board...IIRC) is a California Smog regulatory branch of the government that certifies parts as being smog legal in CA. Any part that is not CARB Certified should not be installed on a car that is to be registered in CA as technically the part would make the car fail smog automatically. This limits the modifications most CA owners can legally do to their cars. (Sucks to be us...)

Christmas Tree - This is a drag racing term. The Christmas Tree is the tower of lights at the starting line of a drag strip. At the top of the tree are a pair of yellow lights on each side. This is the Pre-stage light. When the car approaches the start line this light comes on. The next set of lights down look exactly like the pre-stage lights and are the staging lights. These lights come on when the car is at the starting line. Once both cars are Staged in the Staging lights the starter will start the tree. The next three lights down on the tree are all yellow. If you are running a "Pro tree" all these lights will come on at once. If you're running a three light tree, these will come on in succession from top to bottom with about a half-second delay between each light. Once the last yellow light comes on the next light is the green go light. Below the green go light is a red light. If this red light comes on it means the car left the line before the green go light had illuminated (see Red Light below).

Cold Air Intake (CAI) - A Cold Air Intake is an aftermarket part that will replace your stock air box. Your stock air box is the black plastic part that begins with the box that holds your air filter and continues up to the throttle body on the engine. The stock air box and intake is usually fairly efficient at bringing in air to the engine but an aftermarket CAI will do a better job and free up some horsepower (about 3-10 horsepower at the wheels). However, not all CAIs are actually Cold Air Intakes at all but rather just a better flowing intake. A TRUE CAI will draw air from a location that will have cooler air than what the stock air box would have brought in such as a fender (called a Fender Well Intake or FWI) or lower grill opening. The intakes for the Sky currently are not true CAIs but are described as such anyway since they do improve air flow into the engine.

Crank HorsePower (CHP) - This is how much horsepower an engine produces at the crankshaft. This is the number that is quoted by car makers when talking about the power ratings of their vehicles. For instance, the Sky has 177 CHP. While this is useful when comparing cars, it is useless in real world applications since the transmission and drivetrain rob about 20% of this number before it gets to the wheels. This is why Wheel Horse Power (WHP) is less than CHP.

Detonation (also see Knock) - Detonation is caused by a number of different factors and is death for your motor:

1. Lean condition, (you aren't burning enough fuel) The less fuel that is burned the hotter the explosion inside the cylinder becomes. The air/fuel mixture burns hot when all the fuel is being used up and being burned. This sounds like a good thing but what happens is that when it gets too hot you will get a hot spot that develops in the cylinder that acts like a glow plug. This hot spot preignites the fuel before the spark plug sparks. So what happens is the firing order is disrupted and the cylinder will bang against the cylinder wall. This preignition sucks up horsepower because it unbalances the motor while igniting the fuel at the wrong moment. It also blows holes in pistons too. The problem with preignition is that it is easier to do the more it happens. That little bit of burnt aluminum on the piston will heat up faster to create a hot spot again. The lean condition can happen for a number of reasons: #1 too much air from forced induction, you need to keep the air/fuel ratio consistent. #2 Dirty injectors, not injecting enough fuel. #3 The intake air is too hot and as air heats up it expands and takes up more space and this can throw off the air/fuel ratio as well.
Also a lean condition also leads to high exhaust gas temperatures (EGT); the exhaust will actually start to melt the aluminum engine block if it gets out of hand.

2.Timing, if you adjust the timing to far advanced on the motor the spark plug will ignite too fast as the piston is compressing the air. So with more compression you get a bigger "pop" that creates hot spots in the cylinder and they will start igniting the fuel faster then the spark plug. When the computer "hears" knock through the knock sensors it automatically pulls timing or retards timing. This will happen when you try and run 85 octane fuel for example, the computer backs off the timing to allow the slower igniting fuel to ignite when it should and you lose horsepower and mileage. If it's really hot and the air is expanding.
When you add forced induction you must find a way to pull timing with the higher compression because with the higher compression it's easier to detonate.

3. Octane Level.
Running a higher octane level will allow the motor to run more timing which means more power. Also, forced induction requires a combination of less timing and a higher octane. That's why race gas has a higher octane (100 octane, 110, even 120 octane!) so the competitor can run more timing for more power. You'll hear old guys talking about using "airplane fuel" because in the old days there wasn't readily available race fuel so they used aviation fuel which has a higher octane rating then automotive fuel.

4. Air Fuel Ratio.
You need a 12:1 air/fuel ratio to prevent detonation at full throttle. Your car actually switches from continuous loop 17:1 to 12:1 going from idle/cruising to full throttle. 8:1 is way too rich which will "wash out" the cylinders -there ends up being so much fuel that it washes the oil off of the cylinder walls and you end up with the piston rings scraping the cylinder walls.

With any engine customization and especially forced induction you will need the following: Pyrometer-measures your EGTs, if your EGTs get too hot you know that you're running too lean. Wideband 02 gauge-this is a special oxygen that is installed before the cat sensor. This reads the oxygen in the exhaust to determine what the air/fuel ratio is. There are wideband gauges that you can install that will give a constant digital read out. A Wideband is an extremely useful tool that everybody should have that has forced induction. The "pyro" is great too but by the time your EGTS get too hot you have already done the damage.

Double Wishbone Suspension - A specific type of SLA suspension (see below) where both upper and lower control arms are shaped like an "A" in plan view, and the bushings are mostly between the two bushings.

Drag Radials - A type of drag racing tire. Drag radials are tires that still have some form of "tread" on them and generally are still "street legal" meaning you can drive with them on the car on the street. Drag radials will give better traction than regular street tires but will not be as grippy as a Drag Slick.

Drag Slicks - A type of drag racing tire that has absolutely no tread on the tire. They are used to acheive maximum traction at the drag strip. Some believe that a car with drag slicks on it can run up to a half-second faster in the 1/4 mile than if it was equipped with regular street tires. Drag slicks are NOT street legal tires.

Drift - Holding a car in a oversteer condition (a skid) using throttle in order to negotiate a turn.

ECM Reset - See ECM Retune below.

ECM Retune - The Engine Control Module, or ECM, is the computerized brains of your car. Technically it is one of them since you may have a TCM (Transmission control Module), PCM (Power train Control Module which does both engine and trans), and BCM (Body Control Module which controls other various functions like ABS or Air Conditioning settings). The ECM though is what most deal with in performance applications (other than Auto Trans cars which will deal with the TCM/PCM too). There are two things you can do to an ECM, reset it and reflash it. Resetting it does nothing more than clear the information that the ECM tracks as you drive. After you drive for a while the ECM will relearn this information and will be back to the way it was before the reset. An ECM reset will only help if something else was changed on the car (such and an intake, exhaust, or changing from regular to premium fuel) and the ECM needs to relearn the way the engine will now run with the new part. Even then, the ECM would eventually learn the change over time, usually a few days to a week. An ECM reset will only speed up that learning process.

Reflashing the ECM, also known as reprogramming, will actually change the way your ECM manages your car. These changes are permanent (unless you reflash new settings into the ECM) and will not vary once the ECM starts relearning (usually when the ECM is reflashed it will also be reset to learn the new settings). Things such as fuel injector rates, fueling tables, and sensor ranges as well as rev limiters and top speed limiters can all be changed through reprogramming. With our cars, GM incorporated what are being called Nanny Controls that restrict engine power under certain situations. By removing these controls through reprogramming, anywhere from 10-15 WHP is being gained.

Elapsed Time (ET) - ET is a drag racing term and is the amount of time in seconds that it takes a car to go from a dead stop at the starting line to the finish line. It is important to note the length of the track when discussing ET as there are 1/8th mile tracks and 1/4 mile tracks. Also, most tracks will give ETs for distances of 60', 1/8th mile (on a 1/4 mile track) and 1,000' (also for 1/4 mile tracks).

Forced Induction (FI) - This term refers to the addition of a power adder such as a turbo or super charger to force more air into the engine than what the engine would normally draw. FI engines can produce far more power than their Normally Aspirated versions.

Front Wheel Drive (FWD) - A car who's drive tires are up front. Traits that are common to FWD cars is a tendency to PUSH (understeer) when applying too much power or braking too hard into a turn because so much weight is over the front tires which are trying to do multipul tasks at once.

Fuel Injectors - Generally the only time you upgrade your fuel injectors is when they can no longer deliver enough fuel for your engine's current setup. With normally aspirated engines this usually isn't an issue but when you switch over to a power adder such as a turbo, supercharger, or nitrous then you may need to upgrade your fuel injectors to keep up with the additional air (or oxidation in the case of N2O) these power adders provide.

Heads - The heads, technically head with our cars since we only have one, is where your valves and spark plugs are located on your engine. It is here where the intake and exhaust passages to the cylinders are. They are the caps that cover the pistons and cylinders and are responsible for making sure the fuel air charge, and combustion, all take place in the engine where they belong too. Too much boost and the heads can get blown off damaging their gasket. Not a cheap fix to that problem. Heads can be ported and polished to allow better flow and major gains can be had here especially if the valve size is enlarged. Currently I know of no vendor offering Port and Polished heads for our cars.

High-End Power - Basically a generic term for horsepower. If a car accelerates quickly after it is moving and high in it's RPM range it is said to have good High-End or Top-End power.

Horsepower - Ah yes, the all mighty Horsepower. But what exactly is horsepower? In a nutshell, horsepower is the engine's rated ability to keep a load moving at speed. For instance, when you're cruising on the freeway up a hill (not towing) and maintaining your speed, that's horsepower. When you are accelerating at freeway speeds, this is also a matter of horsepower. For details on Crank Horse Power (CHP) or Wheel Horse Power (WHP) please see those respective deffinitions. Horsepower is also commonly refered to as Top End power. To simplify (thanks to Devil Dog for this), Torque gets you moving, horsepower keeps you moving.

Intercooler (I/C) - An intercooler is used only in FI applications. When air is compressed, it heats up. A hot intake charge increases your chances of getting knock to the point where it is a certainty. The more you compress it (more boost) the hotter it gets and the more likely your engine will die. An intercooler goes between the turbo or super charger and the intake manifold. Hot compressed air out of the IC or S/C flows through the Intercooler which cools down the charge as it is on its way to the intake manifold.

There are two types of Intercoolers, Air to Air and Water to Air. And Air to Air I/C will pass the charge through a heat exchanger on the front of the car and allow cool air passing over it to cool it down. A Water to Air I/C will take the hot intake charge and pass it over a series of coils filled with water. This cools the intake charge rapidly before it goes into the engine. Usually, Air to Air I/Cs are found on turbo units while Water to Air I/Cs are usually found on S/C applications. Of the two, Water to Air I/Cs are more effective but heaver and can leak or have a water pump failure rending the I/C useless. I/Cs don't necessarily give you power but rather allow you to run more boost without getting knock thus getting you more power.

Independant Rear Suspension (IRS) - No, it's not tax season. IRS means the car has completely independant rear suspension components for each rear tire. Older muscle cars had one solid rear axle (and most trucks still do) that didn't allow truely independant rear suspensions. Generally, these solid rear axle suspensions are better for drag racing because they transfer power to the ground and manage chassis flex better. IRS rear suspensions are better for handling corners as each tire can react to road conditions independantly of the other and thus maintain a better contact patch under varying conditions.

Knock (KR for Knock Retard, the ECM's way of fighting Knock. Also see Detonation above.) - KNOCK IS BAD. I put it here because as you increase your power your chances of getting knock increases too. To get rid of knock is to allow the engine to breath better, reduce boost, increase fueling, or cool the intake charge/cylinder. Once you start making big changes, scanning for KR becomes a must. There are a couple very expensive tools out there at the moment that will do this but I imagine more and less expensive options will come out as more people modify these cars. For every degree of timing you gain about 5 hp. So if KR is taking away 3 degrees, you're loosing about 15 WHP from KR.

Long Tube Headers - Headers, any kind of headers, will replace your stock exhaust manifold. Like the exhaust itself, the stock exhaust manifold is built to be easily and quickly produced with little concern over flow. Headers are used to rectify this issue. One of the major things with the exhaust manifold part of the exhaust system is timing. Yes, timing. While the engine is running, no two pistons are firing at the same time. As such an Exhaust Pulse is sent into the exhaust system for each cylinder after it fires. This exhaust pulse should arrive at the cat (since we are talking a single cat, single pipe exhaust system) alone. With the stock exhaust manifolds, two exhaust pulses can reach the cat at the same time thus causing more back pressure in the exhaust system than is optimal (a little backpressure is actually a good thing as it keeps raw fuel coming into the cylinder for the next firing cycle from slipping out the exhaust port un-burnt thus causing a lack of power and excessive fuel consumption). Headers are thus built with all of their tubes being equal in length from the exhaust port on the engine's head to the header's collector, the part where all the exhaust pipes on the header all come together (four in our case...one for each cylinder). By being equal length, this helps to make sure only one exhaust pulse hits the cat at any given time.

Also, the stock exhaust manifold is not very smooth and does not allow exhaust gasses to flow freely out of them. Headers, on the other hand, use pipes that are uniform, smooth, and free of any sharp angles or bends to allow the exhaust gasses to flow freely.

Long Tube headers are headers where the tubes leave the engine and the collector is under the car. The stock Cat needs to be removed and replaced with an aftermarket cat mounted in a location further down the exhaust system. In some states, it is illegal to relocate the cat in this manner for smog purposes and doing so will result in an automatic fail on your smog test. Most will tell you though that there is more power to be gained using long tube headers and a relocated cat than using short tube headers and the stock cat. Power gains from Long Tube headers are in the 8-15 WHP range.

Low-End Power - This is a generic term for torque (see below). Basically if a car can accelerate from a low speed very well it is said to have good low-end power.

Normally Aspirated (NA) - An engine that does not have a turbo or supercharger but rather just sucks air into the throttle body on it's own is said to be Normally Aspirated. The standard Sky is a NA car while the Redline would be considered a Forced Induction (FI) car because of the turbo charger.

Oversteer (Loose) - Oversteer is when the front tires have traction but the rear tires have lost traction and the car is entering a spin. If the driver is able to maintain the skid and prevent it from becoming a spin it is called a Drift and can be used to negotiate turns especially in poor traction conditions. Oversteer is often refered to as being "loose".

Reaction Time (RT) - This is a drag racing term. It is how quickly you get your car moving after the green light comes on at the Christmas Tree. Usually most racers anticipate this light and "go" on the third yellow. The reason for this is that the time it takes for your mind to react to what your eye is seeing then send the proper signals to your foot to do it's thing added to the length of time it takes the car to react to the gas being pressed takes about the same time as it does for the tree to go from that third yellow to green. Some racers can "cut a perfect light" which means they can go at the exact time the light comes on (a .000 light) but really anything under a tenth of a second (0.100) is pretty good. If you go too soon though you "Red light" and automatically loose the race unless the other car red lights too.

Rear Wheel Drive (RWD) - The drive tires of the vehicle are in the rear. The Sky/Solstice are RWD. Handling traits of a RWD vehicle include a propensity for Oversteer (Loose--see below) when power is applied. In most situations this only happens when turning but can happen during launch with high horsepower vehicles. However, if the oversteer condition can be controlled with throttle application the car can be "drifted" through the turn.

Red Light - A drag racing term. If you "red light" it means your car started to leave the starting line before the green light illuminated on the Christmas Tree. A red light is an automatic loss so long as the car in the other lane did not also red light.

Short-Long Arm (SLA) Suspension - A type of suspension which consists of two basic linkages, called control arms, creating a front-view 4-bar kinematic linkage of the wheel/tire to the body. It consists of a shorter, triangular shaped upper control arm and a longer lower triangular shaped control arm to provide camber changes of the wheel during suspension travel. The arms in plan view may be shaped like an "A" (also called a "wishbone") where the ball joint is between the two bushings (like the kappa front upper control arm), or they may be more "L" shaped (like the kappa front lower control arm) where the ball joint may be more in line with one of the bushings for decoupled handling and ride control. SLA suspensions are sometimes called "Double Wishbone" but in many cases is not technically accurate if one of the control arms is really an "L" arm.

Short Tube Headers - (for a definition on headers in general, please see Long Tube Headers above) Short tube headers work like long tube headers with one major difference. Short tube headers bolt up to the stock cat in the stock location and thus allow the stock cat to remain in the stock location. This makes short tube headers more smog friendly come registration smog check time. The drawback to short tube headers is that they do not produce as large of power gains that long tube headers will. (The exception to this is if the stock cat is replaced with a straight tube. However, this set up is also not legal for smog and kind of defeats the purpose of short tube headers to begin with since pricing is so similar between the two setups.) For those that live in smog conscious states and don't want to swap out their entire exhaust come smog test time, short tube headers are probably the way to go. Power gains for short tube headers with the stock cat is around 4-8 WHP.

Slicks - See Drag Slicks

Staging Lanes - This is where you line up and wait for your turn to make a pass at a drag strip. Not to be confused with the Staging area at the starting line, the staging lanes are usually assigned in pairs to different classes that will be using the same track on the same day. When a class is to start racing, their staging lane number(s) is called and only cars in that lane (or lanes if there are a pair for the class) are allowed to proceed to the water box and staging area of the track.

Super Charger (s/c) - A super charger is a power adder that forces more air into the engine than the engine can draw in on its own. There are three types of super chargers: Roots, twin screw, and centrifugal. All are driven by the engine using a belt. Because the engine powers these super chargers, some of the engine's horsepower is used to accomplish this feat. This is called parasitic drag and can be 40-60 hp on some applications. However, the power added by the super charger is usually MUCH more than this and well worth the parasitic drag loss. With super chargers, the smaller the pulley you use on them the faster the rotors spin and the more boost you produce at the expense of having a Higher intake air charge temperature.

A roots blower is just that, a blower. Incoming air is pushed into the engine to create boost. The air colliding with the intake manifold causes the incoming air to "stack" since more air is being blown in than the engine take in at a time and this stacking is seen as boost since the pressure of this air is greater than the outside air pressure. The problem with the roots blower is that it is very inefficient and generates a lot of heat.

A twin-screw supercharger looks very similar to a roots blower. However, the two impellers inside a Twin Screw is compressed before it is blown into the engine. The result is a cooler air charge than a roots blower and more power since it is easier for the engine to turn a twin screw than a roots thus less parasitic drag loss.

A Centrifugal Super Charger (CSC) uses a turbine instead of rotors to compress the air going into the engine much like a Turbo Charger would. This makes it smaller than a roots or twin screw. Also, they are generally easier to install on a car that was normally NA than a roots or twin screw as well. However, these CSC generate a lot of heat and because of their need to be spun by a belt are not as flexible in installation options as a turbo.

Installing a super charger, depending on the engine and the type of super charger, can net big WHP gains of around 100+ whp.

Throttle body (TB) - The throttle body replaces the carburetor in a fuel injected car (along with the fuel injectors of course). The throttle body is where the intake connects to and regulates how much air is coming into the car. When you press on the gas pedal you are opening the throttle body. A larger throttle body can allow you to get more air into the car and can be more beneficial on FI cars than NA cars. The Sky/Solstice have a "Drive by Wire" throttle body. This means that rather than a physical cable going from the gas pedal to the throttle body that there are sensors and motors that will control how the throttle body opens in relation to the gas pedal position.

Top-End Power - See High-End Power.

Torque - Everyone knows about horsepower but few understand that torque is just as important, and sometimes more important, than horsepower. Torque, in a nutshell, is the force used to accelerate your car from a stop. (It is also important for towing purposes but we're not driving trucks here.) For instance, the Sky has 166 ft/lbs (read that as foot pounds) of torque. You'll note that the number is fairly close to the horsepower rating of 177. This is important. Many manufacturers will tune a car to have high horsepower numbers but very little torque. For instance, the 2006 Honda Civic Si has an impressive 197 HP. But then look at it's torque...139 ft/lbs. This is why acceleration in some cars that have impressive horsepower numbers seem to accelerate kind of weak until they get higher up in their RPM range. Torque is your low end power and the more of it you have the faster you can accelerate from a stop. To simplify (thanks to Devil Dog for this), Torque gets you moving, horsepower keeps you moving.

Trap Speed - Another Drag Racing term. When a car runs down a drag strip there are a set of lights at the finish line that calculates how fast the car is going at that point. That speed is called the car's Trap Speed (or just Trap for short...ie: "My car trapped at 104 mph"). Most 1/4 mile tracks will also have a trap speed at the 1/8th mile mark too.

Turbo Charger - Who hasn't heard of this. A turbo charger has two fans connected by a shaft inside of a round housing. When one fan is turned by the exhaust gasses passing through it, it spins the shaft which turns the turbine fan into a big air compressor. The turbine compresses the incoming air and makes boost. The potential of turbos is nearly limitless. However, they have their drawbacks. First they do make a lot of heat. Second, if not properly controlled a turbo can build more boost than the engine can handle very quickly. Also, this is a bit of a lag between when the driver mashes the gas and when the turbo reacts to the increased exhaust gas and the time it takes to get the turbine moving faster. However, a smaller turbo producing less power (of course) will spool up much faster than a large turbo. This is why there are twin turbo applications...to get the most boost out of the car with no turbo lag. Also, turbos are more flexible as to where they can be installed. Again, properly tuned turbos can get 90 WHP and up depending on the application and what size turbo you get.

Understeer (Tight or Push) - When the rear tires have traction but the front tires do not we call this Understeer. This only happens when the vehicle is attempting to turn whereas oversteer can happen due to an overabundance of power while accelerating in a RWD (and sometimes AWD) vehicle. Understeer is usually a desireable trait to have in a car when driven by novice drivers as it is easier to detect and correct in time to prevent major accidents than oversteer. FWD cars are notorious for displaying understeer handling traits.

Valves and Valve Springs - Valves are what let air in the cylinder (intake valve) or exhaust out (exhaust valve). Valve springs close the valves and are critical in making sure the valve is fully closed before the piston reaches the combustion part of it's stroke. By increasing the size of your valve (which also requires head work) you can get more air in and out of your engine. However, if you have a cam with a big lift you need to make sure you have strong valve springs to prevent valve float (valves staying open longer than they should because the spring can't close them fast enough) and a damaged engine. Currently I know of no aftermarket valves for the 2.4L ecotec.

Water Box - See Burn Out Box.

Wheel HorsePower (WHP) - This is how much horsepower the car is actually putting to the ground. Manufacturers will use Crank HorsePower (CHP) in their specifications but how much power is reaching the ground is much less. For instance, the Sky is rated at 177 CHP but will usually put down about 145 WHP. When people talk about dyno numbers, they are refering to WHP, not CHP. There is about a 20% drop from CHP to WHP because of the transmission and drivetrain so an increase of 10 WHP is roughly equal to a 12 CHP increase.



This is the basics that I can think of at the moment. I'm getting tired and need to walk away from the computer for a bit. Please feel free to correct or add any information to this list and I'll update it next time I'm around.

Hope this helps some of you novices out there...(not that I'm an expert or anything...certainly not...)
 

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Thanks -- I enjoied this very much!

Helps to interpret when car-peeps are talking:lol:
 

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Excellent post. Great info for those new to aftermarket modifications. One thing I might add is a section on what to do with WHP once you get it.

Those with the stock sky's don't have to worry about wheel spin, but once you start getting into forced induction (i.e. the sky redline) managing wheel spin becomes your next problem... Adding 100whp to your stock suspension, wheels, tires, and brakes is a good way to lose control of your car...and that happens to all the time. :nono: All significant performance mods should include upgrades to these components to compensate for the additional power, acceleration, and speed the car will now attain. Driver skill and experience also figure into the equasion. :thumbs:
 

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Thanks, I was just about to start a thread asking for this exact information.
 

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Woof! Woof!

(That's my other dog imitation.)
 

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Discussion Starter #8
CyaL8r said:
Excellent post. Great info for those new to aftermarket modifications. One thing I might add is a section on what to do with WHP once you get it.

Those with the stock sky's don't have to worry about wheel spin, but once you start getting into forced induction (i.e. the sky redline) managing wheel spin becomes your next problem... Adding 100whp to your stock suspension, wheels, tires, and brakes is a good way to lose control of your car...and that happens to all the time. :nono: All significant performance mods should include upgrades to these components to compensate for the additional power, acceleration, and speed the car will now attain. Driver skill and experience also figure into the equasion. :thumbs:
Your absolutely right. My issue is that all my information on this is limited to FWD drag racing which is WAY different than an IRS (Independant Rear Suspension) Rear Wheel Drive car. That and all my launch experiance has been with an Auto Trans, not a manual. (Just got into drag racing a little over a year ago)

Now there are the obvious things that transfer over such as grippier tires but other than that I'd be at a loss. Hence why I know there is a LOT more to add to this and rely on those that have done it to share their experiances.

Not only that my my "Modding Principles" theory is for another thread. LOL ie, how you need to make sure that with added power comes added control and whatnot.
 

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What you realy need to know and understand before any forced induction

Detonation (Knock):
Detonation is caused by a number of different factors and is death for your motor:

1. Lean condition, (you aren't burning enough fuel) The less fuel that is burned the hotter the explosion inside the cylinder becomes. The air/fuel mixture burns hot when all the fuel is being used up and being burned. This sounds like a good thing but what happens is that when it gets too hot you will get a hot spot that develops in the cylinder that acts like a glow plug. This hot spot preignites the fuel before the spark plug sparks. So what happens is the firing order is disrupted and the cylinder will bang against the cylinder wall. This preignition sucks up horsepower because it unbalances the motor while igniting the fuel at the wrong moment. It also blows holes in pistons too. The problem with preignition is that it is easier to do the more it happens. That little bit of burnt aluminum on the piston will heat up faster to create a hot spot again. The lean condition can happen for a number of reasons: #1 too much air from forced induction, you need to keep the air/fuel ratio consistent. #2 Dirty injectors, not injecting enough fuel. #3 The intake air is too hot and as air heats up it expands and takes up more space and this can throw off the air/fuel ratio as well.
Also a lean condition also leads to high exhaust gas temperatures (EGT); the exhaust will actually start to melt the aluminum engine block if it gets out of hand.

2.Timing, if you adjust the timing to far advanced on the motor the spark plug will ignite too fast as the piston is compressing the air. So with more compression you get a bigger "pop" that creates hot spots in the cylinder and they will start igniting the fuel faster then the spark plug. When the computer "hears" knock through the knock sensors it automatically pulls timing or retards timing. This will happen when you try and run 85 octane fuel for example, the computer backs off the timing to allow the slower igniting fuel to ignite when it should and you lose horsepower and mileage. If it's really hot and the air is expanding.
When you add forced induction you must find a way to pull timing with the higher compression because with the higher compression it's easier to detonate.

3. Octane Level.
Running a higher octane level will allow the motor to run more timing which means more power. Also, forced induction requires a combination of less timing and a higher octane. That's why race gas has a higher octane (100 octane, 110, even 120 octane!) so the competitor can run more timing for more power. You'll hear old guys talking about using "airplane fuel" because in the old days there wasn't readily available race fuel so they used aviation fuel which has a higher octane rating then automotive fuel.

4. Air Fuel Ratio.
You need a 12:1 air/fuel ratio to prevent detonation at full throttle. Your car actually switches from continuous loop 17:1 to 12:1 going from idle/cruising to full throttle. 8:1 is way too rich which will "wash out" the cylinders -there ends up being so much fuel that it washes the oil off of the cylinder walls and you end up with the piston rings scraping the cylinder walls.

With any engine customization and especially forced induction you will need the following: Pyrometer-measures your EGTs, if your EGTs get too hot you know that you're running too lean. Wideband 02 gauge-this is a special oxygen sensor that is installed before the cat sensor. This reads the oxygen in the exhaust to determine what the air/fuel ratio is. There are wideband gauges that you can install that will give a constant digital read out. A Wideband is an extremely useful tool that everybody should have that has forced induction. The "pyro" is great too but by the time your EGTS get too hot you have already done the damage. Robotech did you have either when you blew your motor up?
 

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Thanks for the input guys...and I will be changing the name I think since the scope is growing. :)

As for your question brady, no I wasn't. The Grand Prixs are notorious for "chipping" pistons. What happens is they get just a little too hot and our rings expand. The end gap will close and the ring will expand into the cylinder. When it does, it gets stuck at the top of the stroke and tries to lift up as the piston travels down. The material in the piston above the ring is so thing that the piston will actually chip off as the ring lifts. (Always occures right at the 2:00 position it seems.) We really don't get detonation per se. In my case the piece that chipped off didn't clear the engine clean and a piece hung up the exhaust valve. Not pretty.

I was scanning my car at the time though (we can read what the computer is doing through the ODBC II port) and what the main cause of the damage turned out to be a chain of events.

The blower I have (new Whipple) drew in a lot more air than we had hypothosized. With a 3.75" pulley it was SUPPOSED to be making between 13 and 15 lbs of boost. At 60% throttle it was over 14.7 (stock 2-bar Manifold Air Pressure or MAP sensor tops out at 14.7) and the Mass Air Flow, or MAF, sensor maxes at 11,500...and I saw 11,600. Over 11,500 the fueling system doesn't know what to do and shuts down injectors. When it went over 11,500 the narrow band O2s dropped to as low as 25 (900 is about where they SHOULD be) so we know it was a seriously lean condition that caused mine but it happened so quickly we had not idea it was going to happen. 1 second is all it took...
 

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How much power could be added to a stock Sky before the handling characteristics changed noticably? If I understand correctly, when starting at 177hp, adding about 20whp through CAI and cat back is approximately a 10% power increase. Would this impact handling mandating suspension changes?

Also, where would the extra power be felt? For example, would there be more power starting from a full stop, or accelerating from 40 to 80?

M Sky zips along, but I would not mind a bit more power. I'm not sure it needs the additional 83hp the turbo in the Redline adds, but a little more would be nice. How much power would need to be added to make a noticable difference?

This is a GREAT thread, thanks!
 

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jarcher said:
How much power could be added to a stock Sky before the handling characteristics changed noticably? If I understand correctly, when starting at 177hp, adding about 20whp through CAI and cat back is approximately a 10% power increase. Would this impact handling mandating suspension changes?

Also, where would the extra power be felt? For example, would there be more power starting from a full stop, or accelerating from 40 to 80?

M Sky zips along, but I would not mind a bit more power. I'm not sure it needs the additional 83hp the turbo in the Redline adds, but a little more would be nice. How much power would need to be added to make a noticable difference?

This is a GREAT thread, thanks!
It would be pretty difficult to feel 20 horsepower but teh car will feel a bit snappy. Most people just perceive the added noise as more power though.
 

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Discussion Starter #16 (Edited)
:agree:

20 hp is virtually inperceptable to the "butt dyno" for most. As far as where the power would be, that all depends on the modification to get it and then you look at your dynos. Usually stuff like exhaust and intake will give it to you across the board but some have been known to see more drastic changes in low end torque with these modifications as well (not Skys...just in general).

As for power and handling, really there are only a couple things that power does to affect handling. First, is how quickly the rear tires will break loose under heavy acceleration. More power means it is easier to break those rear tires loose when cornering. This is where throttle control comes in. Secondly would be weight transfer. Harder acceleration and a more responsive throttle can cause more weight to transfer faster to the rear wheels. Lastly, corner entry speed can be changed too when you increase power since you may be able to accelerate to a faster speed before entering the next corner. This is more of a change in driver technique though than handling changes.

Also, I added Crank HorsePower, Wheel HorsePower, Horsepower, Torque, Low-End power, and High (or top)-end power to the list too.
 

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Robotech said:
:agree:

20 hp is virtually inperceptable to the "butt dyno" for most.
Okay, thanks for the posts folks! If I were interested in being able to accelerate more quickly when I'm already up to about 50, so I could pass more quickly, how much power would need to be added to make a difference? The RL only adds about 80hp, which is about 33% over the Sky, but people talk as if that makes it a rocket.
 

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Discussion Starter #18
jarcher said:
Okay, thanks for the posts folks! If I were interested in being able to accelerate more quickly when I'm already up to about 50, so I could pass more quickly, how much power would need to be added to make a difference? The RL only adds about 80hp, which is about 33% over the Sky, but people talk as if that makes it a rocket.
Well, 20 hp more will allow you to pass "more quickly"...just not a lot more. I'd say you'll definately feel 40 horses. Those of us who are really in tune to our cars will feel 20...but it is a very minor change really.

The Sky takes the quarter in about 15.7...on a really good day.
The Redline does it in about 13.9 seconds. (Don't forget the Redline has different gear ratios than the base Sky. It is quicker to accelerate because of this.)

Now, just under 2 seconds doesn't sound like much but go stand next to a busy highway who's speed limit is 65 mph and, when a car passes you, count off two seconds and see how far down the road it is. And that's at 65. A 13.9 usually results in a trap speed in the 90 mph range. 80 hp is a very big difference.
 

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Robotech said:
Now, just under 2 seconds doesn't sound like much but go stand next to a busy highway who's speed limit is 65 mph and, when a car passes you, count off two seconds and see how far down the road it is. And that's at 65. A 13.9 usually results in a trap speed in the 90 mph range. 80 hp is a very big difference.
Sorry for the stupid question, but what is "trap speed" ?
 
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