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duminică, 25 decembrie 2011

Your Cars Electrical System

Your Cars Electrical System

by: Kevin Schappell


When the automotive industry was in its infancy, it used electricity only to ignite the fuel inside the engine. By the late 1920's, the electric starter replaced the hand crank, electric headlights made acetylene lamps obsolete and the braying of the electric horn drowned out the squeak of the hand-squeezed air horn. Today, an automobile requires an elaborate electrical system of circuits just to produce, store, and distribute all the electricity it requires simply for everyday operation.


The first major component in the electrical system is the battery. The battery is used to store power for starting, and for running auxiliary devices such as clocks, radios and alarms when the engine is off. The next major component is the starter motor, which is used to start the engine. The third component is a charging device powered by the engine, known as the alternator. It powers the electrical system when the car is running, and restores the charge within the battery. With these basic components, the car maintains its supply of electricity. A device called the voltage regulator keeps the power level stabilized, and the fuse box keeps minor problems from becoming major ones.
Many different auxiliary electrical devices are used in modern cars, such as: radios, cellular phones, rear window defrosters and electric door locks, as well as a vast array of motors powering everything from the moon roof on down.
The above information is directly from the Auto Insight program, which you can buy online from AutoEducation.com.
Common Problems:

The battery is usually the first part of the system to wear out. Most batteries last between 3 and 7 years depending on brand and design. Batteries can be fine on minute, and dead the next. More on this later.
Blown fuse: Is one part of the electrical system not working like the interior lights or dash lights? The first thing to check is the fuses. Look for the fuse panel under the dash, in the glove box, or even in the engine compartment in some cars. Most fuse boxes will be labeled by circuit. Modern cars use a blade type fuse which is rectangular in shape and transparent. Look for the wire, which runs through the fuse, and see if it is burned through. Any discoloring of the fuse is a good sign the fuse has blown. If you have doubts, replace with a new fuse and test the system, which is not working.
Alternator: Does your car start ok, but your headlights dim when idling. It could be a bad alternator. When the alternator cannot produce enough electricity to keep the electrical systems running and the battery will have to be used to take up the slack. This will eventually wear down the battery and not allow your car to start.

Troubleshooting:
I don't think there is a tougher system to troubleshoot on your car than the charging/starting system. This is due to the fact that there are many things that can go wrong and it's tough to test some components without special equipment. Let's go over some possible situations and their possible causes.

Car won't start, all I hear is a click but the engine does not turn.

First check all battery cables for corrosion as this will keep power from flowing freely to the starting system. If they are dirty, clean with a wire brush and reattach. Apply a light coat of grease to the top of the terminals to prevent further corrosion.
Battery could not have enough power stored in it to spin the engine. This can be caused by a bad cell in the battery or from a bad alternator not charging the battery when the engine is running. If you can get the car to a mechanic, have him or her test the battery and charging system with a special tester. This tester places a load on the battery and can tell the condition. They can also check to see if the alternator is working to it's full potential.
Starter or solenoid could be bad. If you can not jump start the car and all of the battery cables are ok then suspect the starter.

Car won't start, I hear nothing.

Check battery cables as above.
Have the battery tested. There could be a bad cell causing a short. You can try jump-starting but often the car will not stay running.

Car won't start, all I hear is a horrible grinding noise.

Grinding noises point to the starter not properly meshing with the flywheel. This can be caused by a bad solenoid or a bad spot on the flywheel.
I have also seen starters loosen up so they no longer contact the flywheel at the proper distance. While not common, it is something to keep in mind.

Car starts but my headlights are dim at low engine speeds.

Look to the alternator for problems. Take the car to your mechanic to have the alternator checked for proper operation.
Check for loose wires going to the alternator. Also check for corrosion, as this will inhibit the alternator from charging properly.
Check the tension on the alternator belt. If it is too loose, the belt may slip and not drive the alternator properly.


As you can see there are plenty of things to go wrong with the charging system and it is always best to take the car to your mechanic and have it tested before you go replacing parts blindly.
Preventing problems with your electrical system:

Replace your battery every 4 years as a safety measure. It will save allot of headaches down the road.
If your battery is not a sealed unit, check fluid levels in each cell. Only fill with distilled water and be careful around the acid, which is in the battery.
Check your alternator belt frequently for cracks and tension. Replace per your cars manufacturers recommendations.
Clean your battery connections at least once a year. Parts stores sell a handy terminal cleaner which is basically a round wire brush, which works wonders. Once you reattach the terminals, coat with a layer of heavy grease or special purpose grease sold at parts stores. This layer will block the air from reacting with the connectors and creating corrosion.

How to jump start your car:
Jump-starting your car does not have to be a hard task. First lay out the cables on the ground between the two cars. Make sure that the cable is not tangled and none of the end clamps are touching each other. The car with the good battery should be running.
Step 1: Take the positive (red) clamp closest to the car with the good battery and hook it to the positive terminal of that car. The positive terminal will have a + sign on it and usually a red wire running to it.
Step 2: Repeat this step on the car with the bad battery, hooking up the positive clamp to the positive terminal on the battery. Make sure the clamps are contacting well and can not fall off.
Step 3: Take the negative cable (black) closest to the car with the good battery and hook it to the negative terminal of the battery. The negative terminal will have a - sign and usually a black wire running to it.
Step 4: This is the last step and the most important. Take the negative clamp closest to the car with the bad battery and attach it to a bare metal part of the engine. DO NOT hook it to the batteries negative terminal as there maybe hydrogen gas present from the battery and a spark from the connection could cause an explosion.
That's it...... turn the key on the dead car and the car should start. If it does not, try revving the engine on the good car to boost the charge coming from the alternator. If this does not work, try wiggling the cables to assure you have a good connection. GOOD sets of jumper cables are a necessity. I have had cheaper sets not jump-start a dead car. I actually had to double up two cheap sets to get enough current to start my car. The cheaper sets will have thinner cables, which cannot carry enough amperage to start some stalled cars. I would suggest buying a cable, which has 4,6 or 8-gauge wire.






About The Author


Kevin Schappell maintains http://www.carbuyersclub.com where he gives advice on buying, selling, insurance, and financing. A mechanical engineer and car guy, Kevin has decided to spend his online time helping others learn about automobiles. To learn more about how your car works, Kevin has created http://www.mycarwizard.com.
kevin@schappell.com






This article was posted on December 23, 2004

Your Fuel System

Your Fuel System

by: Kevin Schappell


The fuel system feed your engine the gasoline/diesel it needs to run. If anyone of the parts in the system break down your engine will not run. Let's look at the major parts of the fuel system,


Fuel tank: Basically a holding tank for your fuel. When you fill up at a gas station the gas travels down the filler tube and into the tank. In the tank there is a sending unit, which tells the gas gauge how much gas is in the tank.
Fuel pump: On newer cars the fuel pump is usually installed in the fuel tank. Older cars have the fuel pump attached to the engine or on the frame rail between the tank and the engine. If the pump is in the tank or on the frame rail then it is electric and is run by your cars battery. Fuel pumps mounted to the engine use the motion of the engine to pump the fuel
Fuel filter: Clean fuel is critical to engine life and performance. Fuel injectors have tiny openings, which clog easily so filtering the fuel is the only way to prevent this. Filters can be before or after the fuel pump, sometimes both.
Fuel injectors: Most domestic cars after 1986 and earlier foreign cars came from the factory with fuel injection. Instead of a carburetor to mix the fuel and air, a computer controls when the fuel injectors open to let fuel into the engine. This has resulted in lower emissions and better fuel economy. The fuel injector is basically a tiny electric valve, which opens and closes with an electric signal. In the picture below you can see the injectors towards the outer part of the intake. By injecting the fuel close to the cylinder head the fuel stays atomized ( in tiny particles ) so it will burn better when ignited by the spark plug.
Carburetors: A carburetor takes the fuel and mixes it with air without computer intervention. While simple in operation, they tend to need frequent tuning and rebuilding. This is why most newer cars have done away with carburetors in favor of fuel injection.
Common Problems:
I would say the most common problem is a clogged fuel filter. Make sure you follow your manufacturers recommendations as to when you should change the fuel filter. This information should be in your owner’s manual. Symptoms include sputtering at high speeds or engine not starting at all. Always check the ignition system first, if that's ok then the next suspect is the fuel filter.
Next most common problem is the fuel pump failing. Most modern electric fuel pumps can be heard when you turn the key on. If you don't hear the pump running and your car will not start, it could be your fuel pump. The first thing a mechanic will check is the relay, which sends power to the pump. If this is operating correctly then the pump will have to be replaced.
Last but not least are dirty injectors. While the fuel filter does a good job of filtering the fuel, it's not perfect. Over time deposits and tiny particles lodge themselves in the injectors. This can clog and injector and prevent it from delivering the fuel the engine needs. It can also cause an injector to stick open and send too much fuel into the engine. A regular addition of fuel system cleaner like STP Injector Cleaner, or Techtron fuel system cleaner can help keep your injectors clean. Most gas stations, department stores and all automotive parts stores will have a good cleaner available. Add it to your empty tank right before you fill up and it will clean as you drive. I recommend doing this every 3 months to keep your injectors performing like new. Mechanics also offer a cleaning service where they actually disconnect the fuel line and flush cleaner through the engine. This is only necessary when you let your injectors get to a point where they can not be cleaned by a store-bought product. Regular use of a good in-tank cleaner will keep you from having to pay for this service.
Where do you buy your gas?
Believe it, or not, it can make a difference. Always buy from a well know national brand service station. Gas stations, which are not affiliated with one brand of gas, tend to get whatever is left at the end of the day from the delivery truck. One day them might get Texaco, and Exxon another. Also water mixed with gas will cause problems with your engine. The engine will not run right, plus the water will promote rust in the fuel system. I have experienced this when I purchased gas at some no-name gas stations. Your car will feel sluggish and sometimes refuse to run if there is enough water in the gas.
Octane rating tip!!!!
Putting super in the tank will not get you any more performance or gas mileage unless specifically recommended by your cars manufacturer. If your owners manual says put in 87 octane...... DO IT. You are throwing money out the window if you are filling up on Super or Premium and you only need Regular.






About The Author


Kevin Schappell maintains http://www.carbuyersclub.com where he gives advice on buying, selling, insurance, and financing. A mechanical engineer and car guy, Kevin has decided to spend his online time helping others learn about automobiles. To learn more about how your car works, Kevin has created http://www.mycarwizard.com.
kevin@schappell.com






This article was posted on December 23, 2004

Auto HVAC

Auto HVAC

by: Kevin Schappell


Not only do we depend on our cars to get us where we want to go, we also depend on them to get us there without discomfort. We expect the heater to keep us warm when it's cold outside, and the air conditioning system to keep us cool when it's hot.


We get heat from the heater core, sort of a secondary radiator, which is part of the car's cooling system. We get air conditioning from the car's elaborate air conditioning system.
Despite its relatively small size, the cooling system has to deal with an enormous amount of heat to protect the engine from friction and the heat of combustion. The cooling system has to remove about 6,000 BTU of heat per minute. This is a lot more heat than we need to heat a large home in cold weather. It's good to know that some of this heat can be put to the useful purpose of keeping us warm.
Air conditioning makes driving much more comfortable in hot weather. Your car's air conditioner cleans and dehumidifies (removes excess moisture), the outside air entering your car. It also has the task of keeping the air at the temperature you select. These are all big jobs. How do our cars keep our "riding environment" the way we like it?
Most people think the air conditioning system's job is to add "cold" air to the interior of the car. Actually, there is no such thing as "cold," just an absence of heat, or less heat than our bodies are comfortable with. The job of the air conditioning system is really to “remove” the heat that makes us uncomfortable, and returns the air to the car's interior in a "un-heated" condition. Air conditioning, or cooling, is really a process of removing heat from an object (like air).
A compressor circulates a liquid refrigerant called Refrigerant-12 (we tend to call it "Freon," a trade name, the way we call copy machines "Xerox" machines). The compressor moves the Refrigerant-12 from an evaporator, through a condenser and expansion valve, right back to the evaporator. The evaporator is right in front of a fan that pulls the hot, humid air out of the car's interior. The refrigerant makes the hot air's moisture condense into drops of water, removing the heat from the air. Once the water is removed, the "cool" air is sent back into the car's interior. Aaaaaah! Much better. Newer cars have R-134 as the refrigerant, but work in the same way as R-12.
Sometimes we worry when we catch our car making a water puddle on the ground, but are relieved to discover that it's only water dripping from the air conditioning system's condenser (no color, no smell, and it dries!).
Note: Refrigerant is extremely dangerous. Many special precautions must be taken when it is present. It can freeze whatever it contacts (including your eyes), it is heavier than air and can suffocate you, and it produces a poisonous gas when it comes in contact with an open flame.
The above information is directly from the Auto Insight program, which you can buy online from AutoEducation.com.
Common Problems:

From time to time the A/C system needs to be recharged to bring it back up to maximum efficiency. Sometimes a leak may cause loss of refrigerant and will need to be fixed before refilling. It's difficult to tell if a leak is present without specific test equipment so let it up to a professional.
Corrosion will cause the heater core (secondary radiator) to leak. This will manifest itself by leaving steam into the passenger compartment and fogging your windows. You will know there is a leak by the sweet smell coming from your vents. Unfortunately changing the heater core is usually not the easier job in the world, as engineers tend to squeeze them into some pretty tight spaces under the dash.






About The Author


Kevin Schappell maintains http://www.carbuyersclub.com where he gives advice on buying, selling, insurance, and financing. A mechanical engineer and car guy, Kevin has decided to spend his online time helping others learn about automobiles. To learn more about how your car works, Kevin has created http://www.mycarwizard.com.
kevin@schappell.com






This article was posted on December 23, 2004

Auto And Trucks

The Cooling System

by: Kevin Schappell


The purpose of the engine's cooling system is to remove excess heat from the engine, to keep the engine operating at its most efficient temperature, and to get the engine up to the correct temperature as soon as possible after starting. Ideally, the cooling system keeps the engine running at its most efficient temperature no matter what the operating conditions are.
As fuel is burned in the engine, about one-third of the energy in the fuel is converted into power. Another third goes out the exhaust pipe unused, and the remaining third becomes heat energy.




A cooling system of some kind is necessary in any internal combustion engine. If no cooling system were provided, parts would melt from the heat of the burning fuel, and the pistons would expand so much they could not move in the cylinders (called "seize").
The cooling system of a water-cooled engine consists of: the engine's water jacket, a thermostat, a water pump, a radiator and radiator cap, a cooling fan (electric or belt-driven), hoses, the heater core, and usually an expansion (overflow) tank.
Fuel burning engines produce enormous amounts of heat; temperatures can reach up to 4,000 degrees F when the air-fuel mixture burns. However, normal operating temperature is about 2,000 degrees F. The cooling system removes about one-third of the heat produced in the combustion chamber.
The exhaust system takes away much of the heat, but parts of the engine, such as the cylinder walls, pistons, and cylinder head, absorb large amounts of the heat. If a part of the engine gets too hot, the oil film fails to protect it. This lack of lubrication can ruin the engine.
On the other hand, if an engine runs at too low a temperature, it is inefficient, the oil gets dirty (adding wear and subtracting horsepower), deposits form, and fuel mileage is poor-- not to mention exhaust emissions! For these reasons, the cooling system is designed to stay out of the action until the engine is warmed up.
There are two types of cooling systems; liquid cooling and air cooling. Most auto engines are cooled by the liquid type; air cooling is used more frequently for airplanes, motorcycles and lawnmowers.
Liquid cooled engines have passages for the liquid, or coolant, through the cylinder block and head. The coolant has to have indirect contact with such engine parts as the combustion chamber, the cylinder walls, and the valve seats and guides. Running through the passages in the engine heats the coolant (it absorbs the heat from the engine parts), and going through the radiator cools it. After getting "cool" again in the radiator, the coolant comes back through the engine. This business continues as long as the engine is running, with the coolant absorbing and removing the engine's heat, and the radiator cooling the coolant.
A cooling system pressure tester is used to check the pressure in the cooling system, which allows the mechanic to determine if the system has any slow leaks. The leak can then be found and fixed before it causes a major problem.
The above information is directly from the Auto Insight program which you can buy online from AutoEducation.com.
Common Problems:
Let's look at the common problems cars have with the cooling system.

Broken hose. Hoses wear out and can leak. Once the coolant has left the system it can no longer cool the engine and it overheats.
Broken fan belt. The water pump is driven by the engine through a belt. If the belt breaks the water pump can not turn and coolant will not be circulated through the engine. This will also lead to engine overheating.
Faulty radiator cap. The radiator cap is designed to hold a certain pressure in the coolant system. Most caps hold 8 - 12 PSI. This pressure raises the point in which the coolant will boil and maintains a stable system. If your cap does not hold pressure, then the car could overheat on hot days since the system never becomes pressurized.
Water pump failure. Most commonly you will hear a screeching noise and will be able to see coolant leaking from the front of the pump or under the car. Early signs are small spots of coolant under the car after being parked overnight and a strong coolant odor while driving.
Head gasket... have large amounts of white smoke flowing out of your exhaust? Could be a head gasket. The head gasket seals the cylinder head to the engine block and also seals the coolant passages. When this gasket fails coolant can enter the cylinder and it will be turned to vapor as the engine fires. Head gaskets most often fail after the engine has experienced an overheating situation. When super hot, the cylinder head can warp and allow the gasket to fail.

Preventive Maintenance:

Check all belts and hoses regularly. (at oil change is a good time)
Look out for coolant leaks underneath the car, they could be signs of trouble to come.
Change your coolant every 2 - 3 years depending on the manufactorers recommendations.
Inspect your radiator cap for deterioration of the rubber seal. Replace if you think it is worn. $5 - $10 is cheap insurance.
Have your coolant system flushed every 5 years. It gets all the corrosion which has built up out of the system.

What to discuss with your mechanic:

Let your mechanic know when your overheating problems occur. Overheating when idling points to a different problem than overheating at highway speeds.
Ask your mechanic if it's worth changing the timing belt or chain while he is replacing your water pump. Many times the timing belt turns the water pump so it has to be removed anyway to access the water pump.

WARNING: Never open your radiator when the engine is hot. The pressure in the system can cause hot coolant to splash out and burn you.






About The Author


Kevin Schappell maintains http://www.carbuyersclub.com where he gives advice on buying, selling, insurance, and financing. A mechanical engineer and car guy, Kevin has decided to spend his online time helping others learn about automobiles. To learn more about how your car works, Kevin has created http://www.mycarwizard.com.
kevin@schappell.com






This article was posted on December 23, 2004

The Exhaust System

The Exhaust System

by: Kevin Schappell


Your car's exhaust system carries away the gases created when the fuel and air are burned in the combustion chamber. These gases are harmful to humans and our environment. A frequent check of your exhaust system is a must to provide for you and your family's safety. Make sure there are no holes in the exhaust system or in the passenger compartment where exhaust fumes could enter. Let's begin by listing the parts of the exhaust system and their functions.
Exhaust manifold: The exhaust manifold attaches to the cylinder head and takes each cylinders exhaust and combines it into one pipe. The manifold can be made of steel, aluminum, stainless steel, or more commonly cast iron.




Oxygen sensor: All modern fuel injected cars utilize an oxygen sensor to measure how much oxygen is present in the exhaust. From this the computer can add or subtract fuel to obtain the correct mixture for maximum fuel economy. The oxygen sensor is mounted in the exhaust manifold or close to it in the exhaust pipe.
Catalytic converter: This muffler like part converts harmful carbon monoxide and hydrocarbons to water vapor and carbon dioxide. Some converters also reduce harmful nitrogen oxides. The converter is mounted between the exhaust manifold and the muffler.
Muffler: The muffler serves to quiet the exhaust down to acceptable levels. Remember that the combustion process is a series of explosions that create allot of noise. Most mufflers use baffles to bounce the exhaust around dissipating the energy and quieting the noise. Some mufflers also use fiberglass packing, which absorbs the sound energy as the gases flow through.
Exhaust pipe: Between all of the above mention parts is the exhaust pipe which carries the gas through it's journey out your tail pipe. Exhaust tubing is usually made of steel but can be stainless steel (which lasts longer due to it's corrosion resistance) or aluminized steel tubing. Aluminized steel has better corrosion resistance than plain steel but not better than stainless steel. It is however cheaper than stainless steel.
Common Problems:
Well the worst enemy of your exhaust system is corrosion.... or more commonly known as rust. Rust is caused by moisture reacting with the iron in the steel and forming iron oxide. Moisture, or water vapor is present in the exhaust as a by-product of combustion and the catalytic converter. Moisture can also come from the outside in the form of rain.
Short trips in your car can shorten the life of your exhaust system. When you shut down your engine whatever water vapor is in the pipes condenses and turns back into a liquid. On a short trip the water never has a chance to get hot enough to turn back into water vapor and just stays in the system and rusts away the pipes. If you drive for short distances consider replacing your exhaust system with stainless steel when the plain steel one rusts through. If you drive more than 15 miles at a time then you should not have to worry about this.
If you live in an area, which uses salt on the roads in the wintertime, make sure to wash the underside of you car with water every few weeks. Salt speeds up the corrosion process and getting it off as soon as possible will help stop the corrosion. Make sure you run the engine after washing to drive off all of the water on the pipes.
Noticing a decrease in your gas mileage? Your oxygen sensor could be going south on you. As time goes on the oxygen sensor begins to wear out and becomes less accurate. This sometimes results in a rich fuel mixture where your engine burns more fuel than is needed. Most of the time your check engine light will come on and alert you to a failing oxygen sensor. I suggest changing the oxygen sensor every 60,000 miles just to be safe. Even though your check engine light might not be on, you could be using more gas than is needed. Pay a few bucks and change the sensor, your wallet will thank you when you have to buy less gas down the road.
The next part in line to go is the muffler. Most of the time mufflers rust through and need to be replaced. There are allot of options out there for replacement mufflers. Some cheap and some expensive. It holds true... you get what you pay for. If you plan on keeping your car for any period of time, spend the extra cash and get an OEM muffler or a high quality name brand muffler.
On rare occasions the catalytic converter will become clogged and need to be replaced. Symptoms include loss of power, heat coming from the floor of your car, glowing red converter or a sulfur smell. Never let a mechanic tell you that you can do without the catalytic converter. Removing this component is illegal in most states and can lead to a hefty fine to the government if you are not careful.
That's about it for the exhaust system; just remember that rust is the biggest enemy to your exhaust system. Take the above-mentioned steps and your exhaust system will last a long time





About The Author


Kevin Schappell maintains http://www.carbuyersclub.com where he gives advice on buying, selling, insurance, and financing. A mechanical engineer and car guy, Kevin has decided to spend his online time helping others learn about automobiles. To learn more about how your car works, Kevin has created http://www.mycarwizard.com.
kevin@schappell.com






This article was posted on December 22, 2004

FAQ on Modifying the Toyota Supra

What does BPU™ stand for? (BPU™ is a trademark of SupraStore.com)Basic Performance Upgrades. These modifications are: A full length three inch down-pipe (with or with-out high flow cats), 3” (75mm) or bigger cat-back exhaust system, raised boost....



FAQ on Modifying the Toyota Supra

by: Stuart B


What does BPU™ stand for? (BPU™ is a trademark of SupraStore.com)
Basic Performance Upgrades. These modifications are: A full length three inch down-pipe (with or with-out high flow cats), 3” (75mm) or bigger cat-back exhaust system, raised boost (18psi), and the required boost cut eliminator (GReddy BCC) needed to achieve that boost without activating the factory fuel cut-off at 14-15psi. These are the modifications that have proven to provide the best HP-to-$$$ ratio.
What does the + mean when someone says BPU™+? And what is APU?
That stands for any additional power producing modifications other than the basic BPU™ modifications. One "+" refers to Adj. Cam Gears and under-drive pulleys, the second "+" refers to a Fuel controller, ECU upgrade, etc. For instance, a Supra with the BPU™ modifications, plus a front-mount intercooler, would be called BPU™+. If you added cam gears to that, it would be BPU™++, and so on. The "BPU™" term is used until you have an upgraded turbo(s). Then it is referred to as APU, advanced performance upgrades. This designation pretty much covers every modification that can be performed.
What are the first engine modifications I should perform?
I recommend starting with raising the boost of the stock turbos to roughly 18psi. This will require a quality boost gauge and a boost cut eliminator (GReddy BCC). You will achieve 15 or so PSI with the stock Down Pipe in place. This will provide an addition of approximately 30rwhp. After those modifications are completed, it would be a logical next step to install the Down Pipe and Cat-Back Exhaust at the same time. You will now be at full BPU™.
What do all the various "Free Mods" do?
There are many different "free mods" for the Supra TT. I will cover just a few of them here. The ones I will cover fall into three categories, boost control, EGR disabling, and TTC or True Twin Conversion.
Three of the boost control mods are: Bleeder-T Mod, Clamp Mod, and the VSV Bypass Mod. Each of these modifications raise boost levels without the use of a boost controller. But you have to keep a close eye on your boost gauge, and make sure they are not allowing the turbos to boost too high (18psi is a safe level).
The next mods, are the true twin conversion mods (or TTC). This modification disables the Sequential twin turbo operation, and causes the turbos to run constantly in parallel (both on at the same time). This is supposed to allow for slightly better mid-range power (before the secondary turbo would normally come online) and allows for a smoother power band, without the abrupt boost increase caused by the transition from primary to secondary operation. However, this does noticeably decrease low-end power, and increases exhaust noise levels, and therefore may not be desirable on the street. Two types of the TTC mod are, the traditional TTC mod which includes 2 methods, wiring the actuators, or installing a one way valve, and the Electronic TTC mod (ETTC).
The last mod I will discuss is the EGR mod. This disables the Exhaust Gas Recirculation system, which is meant for emissions, and therefore, this modification is for off-road use only. This mod is supposed to prevent the super heating of the number 5 and 6 cylinders, which may cause burnt valves.
How much power will my car make at BPU™?
It varies from car-to-car, and the conditions as well as tuning. Most BPU™-only Supra Twin Turbos, dyno between 370 and 410 horsepower at the rear wheels. This is usually achieved with moderate temperatures, a reset ECU (to erase anything bad the ECU may have learned), and often a little bit of high-octane un-leaded race fuel. On the street, power will be reduced, especially in poor weather, but at least 90 percent of the power should be retained.
What kind of 1/4 mile ETs and trap speeds should I run at BPU™-only?
It varies WIDELY depending on driver skill. As well as track conditions, elevation above sea level, ambient temperatures, humidity, and pre-race preparation. But most fall between 12.3 to 12.9 ets with 112 to 119mph trap speeds on street tires. Times can drop well into the 11s with drag radials, a good driver, and good conditions, as well as proper pre-race preparation.
What is a BPU™'d Supra TT's top speed?
Speeds in the mid-high 180mph range should be achievable. Once the speed-limiter is disabled, by pulling the "TRAC" fuse of course.
Will the life of my Engine and Drivetrain be adversely affected with the BPU™ mods?
Yes, but not by a significant amount. If the car is maintained properly, and the car is treated with some respect for the components, you should maintain much of the power train’s life. Which considering the fact that the Supra is by far one of the most reliable and durable sports cars, it will last longer than most well maintained STOCK sports cars. The only Drivetrain components that will see a significantly shortened life will be the stock clutch. It will more than likely not last much longer than 8-10k miles once at BPU™. This especially holds true if the car is making repeated high speed runs using 5th and 6th gear at wide open throttle. If your stock clutch has high mileage on it, or is already starting to slip, you will need to plan on a new high-performance clutch. Also the stock turbos will be subject to a somewhat shortened life span (how short will depend on how you drive and maintain the car, as well as how much boost you will run)
What's the reliability of a 600hp Supra Turbo?
Chassis, electrical, and suspension components should see little effect on reliability on street driven Supras. The stock 2JZ-GTE engine should hold up pretty well to this power level. Just how long depends on maintenance, and how hard you drive it, and how often. But typically Supras can go for years at this power level. The transmission reliability will depend on whether it's an Automatic or Manual. A stock automatic will not hold this much power, a built transmission will be required, and it's reliability will depend on it's design and construction. The 6spd Manual should hold up just fine, as well as the rear differential and axles.
The only real reliability concerns at these low power levels would surround the actual modifications you perform. Excluding installation short-comings, the components utilized, even very high quality ones, may fall short of factory component reliability, as the built in compromises that exist in everything, would lean more towards the side of ultimate performance, than of ultimate reliability (Keep in mind we are talking about a Toyota here, whose reliabilty standards are exceptionally high) This may include fuel system components, turbo components, and especialy electronic wizardry. Basically a set-up that is either VERY well concieved, or utilizes OE components as much as possible, without over burdening them, would posses *near* stock reliability. And tuning of the components, and component selection, and matching, would play a HUGE role in this.
What are the power limits of the various factory components (Differential, Transmission, Motor, etc.)?
There have really not been enough failures to really pin point a limit for the various power-train components. The motor could fail at factory power levels if it was running dangerously lean. But when well tuned, the motors internals (Pistons, Rods, Crank, Head Gasket etc) are reliable to 700rwhp. But of course at these power levels, if the engine is not set-up and tuned properly, it is literally a bomb waiting to go off, however this would be just as true with a built motor. Some owners have pushed their stock internals to the limit and have well exceeded 800rwhp, and even approached 900rwhp. I still don’t understand how such an over built motor made it past the bean counters at Toyota Corporate.
The 6-speed Getrag is ridiculously strong for an OE transmission. Its limit’s will be affected greatly by driving technique, such as launching, and whether or not power shifting is used. Even driven hard, the Getrag should hold up reasonably well with 700RWHP. If you treat it with some respect, it should be able to handle around 800RWHP or more, although great care and respect will need to be practiced at those levels.
Differential, axle, CV Joint, and drive shaft failures are a VERY rare occurrence. So I don't have much info on their failure limits. On street tires, it would be almost impossible to break any of these components at ANY power level. The tires would spin before they would put the driveline under that kind of strain. The tires act sort of like a circuit breaker. If you run drag slicks, this does not hold true of course, yet they have proven themselves to be 10 and even 9 second capable.
Will drivability, interior noise levels, and low-end power be adversely affected with the BPU™ mods?
Drivability is not adversely affected. Interior noise level depends on the exhaust system you choose. Some will make it far louder; some will actually make it quieter. But most are just a little bit louder than stock. But the added dBs are also combined with a MUCH sweeter exhaust note, so it's definitely worth it. And the interior of the Supra is pretty quiet anyway, so on the highway, it will be VERY livable. As far as low-end power goes, the down-pipe will greatly decrease Turbo Lag. So low-end power and response is much improved over stock.
Will emissions be adversely affected by the BPU™ mods?
As long as a high-flow cat is used, emissions should not be effected, and you should still pass visual inspection. If you run without catalytic converters, you are doing so at your own risk, and you would not pass visual or emissions testing.
Will fuel mileage be adversely affected by the BPU™ mods?
If driven calmly, as in light throttle, mileage should not be significantly affected. Mileage will greatly decrease during however, if you drive “vigorously”, more power equals more burned fuel I am afraid.
Should I install an "Intake" (Open Element Filter)?
This is a bit of a yes and no answer. The stock filter assembly is a flow restriction, and an open element intake would increase potential flow. However, it will also draw in more heated engine compartment air, which can hurt performance. My advice is to either modify the stock filter box, or install a cool air induction box, like the Max Air. An added bonus of the open element filters, is that they allow you to easily hear the primary turbo and by-pass valve.
What about the stock intercooler?
The stock intercooler does a decent job up till about 17psi on the stock turbos, after that you would probably notice a significant gain, especially in warmer temperatures, with a nice front mount intercooler. However, keep in mind it will block some of the airflow to the radiator, as well as decreasing response slightly.
Should I replace the factory rubber Intercooler hoses with aftermarket metal hoses?
It wouldn't hurt. But it won’t help a lot either. At the most you may slightly increase throttle response, but at least it will look nicer.
What about the fuel system, are the stock injectors and fuel pump large enough for BPU™?
Yes, the stock fuel system is very safe and reliable to 450RWHP, although I would recommend a fuel pulsation damper bypass. Anything over that, and I would highly recommend having the car dyno’d, and using a wide-band O2 sensor (not a cheap A/F gauge connected to the stock O2) to check the fuel ratio at your high boost setting. 11.5:1 would be a safe fuel ratio.
What are the stock injectors rated at?
540cc/min
Would the Supra benefit from a fuel controller?
BPU™'d Supras run a little on the rich side as far as fuel ratios go. This hurts power. What it does do is provide a safety margin that makes engine damage through detonation unlikely. If you get a fuel controller, and tune it properly (on a dyno, with an accurate EGT gauge, and a high band O2 (The Stock O2 sensors are not accurate), then you should be able to gain a noticeable amount of power. One of the most popular electronic fuel controllers is the A’PEXi S-AFC. The Fields SFC is good too.
What should I use to increase my boost level, an Electronic Boost Controller, or a Manual BC?
Using an EBC is the safest way to raise boost, it will prevent spiking and over-boosting. But it really comes down to your budget. If you can afford an EBC, get one. If you can't, go with a MBC. And always keep an eye on that boost gauge. And whatever you are using to control boost, remember to not get carried away, I don't recommend going regularly over 18psi.
What is the best Electronic Boost Controller?
There really is no BEST. Although the A’PEXi AVC-R is a nice unit, it provides much more control over boost than other EBCs, but it is also more complex to install, and tune. The new Blitz unit is also nice. Most of the large manufacturers make decent units. Just avoid fuzzy-logic equipped models if you still have the sequential stock turbos, they will become "confused" by the unnatural behavior of the sequential system.
When installing my EBC, do I connect it to both of the Turbo's Wastegates?
The Primary Turbo is the only one with a wastegate. When in full twin turbo mode, the boost of both Turbos is regulated by the primary turbo's wastegate. So, only connect it to the Primary's.
Some people say I need to replace my ECU with a reprogrammed one, instead of just using a boost controller. Do I?
Reprogrammed ECUs for the Supra TT are VERY $$$. They are in the $1200 range. And they have not been proven to provide a significant increase in performance or safety on BPU™ level cars. Their merit shows itself on cars with upgraded Turbo(s). Just be sure you buy your ECU, or have it reprogrammed by a reputable shop that knows what they are doing. And have it tailored to your particular car (Driving habits, and Mods). And I would also recommend taking a look at the AEM Programmable system.
What is a safe boost level to run at BPU™?
The general consensus is 17-18psi. Some people have taken it higher, but I don't recommend it if you don’t have the money for a turbo replacement/upgrade.
Which Down-Pipe is recommended?
The RMM (or Rod Millen Motorsports) Cat-less Downpipe is the most commonly used. However many other brands exist. Some down-pipes, such as the Random Technology DP, feature an emissions legal high-flow catalytic converter.
Will a high-flow cat hurt performance?
It will have some effect on power output, but not a lot. Its exact effect on HP is not clear, but it probably costs a few hp at the most, maybe 5-15hp at BPU™ power levels.
What is a Down-Pipe?
It is the section of the exhaust system that connects the outlet of the Turbocharger's Turbine section to the "Cat-Back" exhaust system. The Downpipe is also where the two catalytic converters are located, as well as the O2 sensor (or sensors in OBD-II cars).
I have an OBD2 car. Can I still install a Down-Pipe?
Yes. But unless the DP has a Catalyst and a second location for an O2 sensor, you will trip your check engine light, unless you get one of those O2 “black boxes”.
Which Exhausts are the loudest?
The Tanabe Racing Medallion, and HKS Hiper Titanium seem to be the two loudest systems.
Which Exhausts are the quietest?
The Tanabe Hyper Medallion, the discontinued Tanabe G-Power Medallion and the GReddy (SP) Street Performance seem to be the quietest. At anything less than full throttle, they are no louder than stock. But at full throttle they seem to “wake up” a bit.
What are some recommended exhaust systems?
It depends on your personal preferences. Below I will break down some of my recommendations based on certain combinations of preferences.
Subtle Styling / Very Low Cost:

-Random Technology (75mm, full stainless steel)
Subtle Styling / Low Sound Level / Moderate Cost:

-GReddy Street Performance (80mm)

-Tanabe Super Hyper Medallion (80mm, full stainless steel, 50-state legal)

Subtle Styling / Moderate Sound Level / Moderate Cost:

-ATR (75mm, full stainless steel)

Tasteful Styling / Low-Moderate Sound Level / Low Cost:

-HKS Dragger II (85mm)

Tasteful Styling / Low-Moderate Sound Level / Moderate Cost:

-GReddy Power Extreme (80-94mm)

-HKS Super Dragger (95mm)

Tasteful Appearance / Moderate Sound Level / High Cost / Super Light:

-Veilside Tear Drop Titanium (90mm, full titanium)

Tasteful-Wild Styling / Low Sound Level / Moderate Cost:

-TRD 2nd gen.

Wild Styling / Moderate Sound Level / Low Cost:

-A’PEXi N1

-HKS Hiper (75mm)

Wild Styling / Moderate Sound Level / Moderate Cost:

-A’PEXi GT Spec (95mm, full stainless steel)

-Blitz NUR Spec (80mm, full stainless steel)

-HKS Hiper Carbon/Titanium (75mm, CF wrapped muffler, titanium tip)

Wild Styling / High Sound Level / Moderate Cost:

-Tanabe Racing Medallion (80mm, 50 state legal)

Wild Styling / High Sound Level / High Cost / High Flow:

-HKS Hiper Titanium (104mm, titanium muffler)

What is the cheapest route to replacing the DP and Cat-Back?
Have a custom performance exhaust shop fabricate a complete 3" exhaust system (Turbo-to-Tip). It should cost well less that $400. And then you can use the muffler and exhaust tip of your choice.
Which Fuel Cut Eliminator is recommended?
The GReddy BCC (Boost Cut Controller) is highly recommended.
What does the Fuel Cut Eliminator do?
The factory ECU is programmed to activate a fuel cut if the manifold pressure exceeds 14-15psi. It does this as a safety measure to prevent what the ECU sees as over boosting. The Fuel Cut Eliminator effectively eliminates, or at least raises the cut to a higher pressure. A reprogrammed ECU can also eliminate this function.
Which boost gauge is recommended?
Any high quality boost gauge will work well. Accuracy is the important feature to look for. Autometer gauges are a good value. The Japanese gauges, A’PEXi, GReddy, HKS, etc., have more features, but at a much higher price.
Where can the boost gauge be installed in the interior?
If you want to mount it in the dash, the two most popular places are the Clock location (which holds a 52mm gauge), and the Air Vent beside it (which holds a 60mm gauge). You can also use an A-Pillar gauge pod.
What is the stock boost pressure?
11-12psi
Are Cam Gears a good modification for the Supra TT?
Yes, they have been shown to provide a 5-15rwhp gain on a BPU™'d car. But to extract their potential, you must have them tuned, by a knowledgeable tuner, on a dyno. And most of the power gains will be seen on the exhaust side. I also recommend buying cam gears which feature 5-bolts.
Are Under Drive Pulley(s) a good modification for the Supra TT?
Most of the crank-shaft under-drive pulleys require the removal of the factory torsional damper.
This is from MKIV.com :"this is NOT an external (harmonic) balancer, as the crankshaft is fully balanced, rather it dampens both the axial twisting couples produced by the firing pulses, and the radial bending moment from the accessory drive belt."
Basically this device provides crutial isolation between the engine driven accessories, and the crankshaft. However, removal of this can provide a 10-15rwhp gain, but at a cost for long term use.
Do I need to upgrade the ignition when upgrading to BPU™?
The stock ignition system is VERY capable of supplying enough fire for a BPU™'d car. The stock ignition system uses 6 large coils, one for each cylinder. So the system is capable of supporting VERY impressive HP levels. You may need to change to a colder range plug with a tighter gap (see below).
What about the spark plugs, which are recommended at BPU™ or higher level?
Basically you want similar plugs as stock, but a cooler heat range and a smaller gap. The stock plugs are NGK BKR6EP-11 (2978) and are platinum tipped and have a .044 (1.1mm) gap. The ideal NGK replacement for a modified Supra would be the BKR7E (6097). It is one range cooler (the '7'), is non-platinum tipped (the lack of the 'p') and has a smaller .0315 gap (lack of the '-11'). This plug is also called the NGK 6097 and they are fairly inexpensive. Platinum tipped plugs are not desired for high power applications, Iridium plugs are more prefered. Unfortunately their doesn't seem to be a BKR8E which might be better for high-HP Supras.
Another good plug to try is the Denso Iridium IK22 or IK24. These plugs may last longer than the above mentioned NGKs, but are also 6 times as expensive. The stock replacement plug would be the IK20, the IK22 is one step cooler, and the IK24 is two steps cooler than stock. The IK22 would be good for ~400rwhp to ~600rwhp. The IK24 would probably be a good choice above that. Two other plugs commonly used are the NGK 3330 (BCPR7ES) which differ much more from the specifications of the stock plugs than NGK 6097. Also the Rapid Fire #5 used to be very popular, but are more expensive, don't last as long, and have fallin out of favor. Both of those plugs have been known to cause slight stumbling at idle. Plugs on Supras do not live long, usually around 5,000-10,000 miles. So I recommend replacing them with every other oil change.
What is the HKS VPC and GCC?
It is an electronic device, which electronically and physically removes the highly restrictive mass airflow sensor from the intake tract. VPC stands for Vein Pressure Converter. The HKS GCC is a device that allows further fine-tuning of the VPC.
Do I need an after-market Blow off Valve?
It is not absolutely required, but it is a good idea. The factory by-pass valve is prone to failure, and an aftermarket BOV is probably a wise investment for preventing turbo damaging compressor surge. And it sounds cool too. However, it must be noted that if you still have the factory mass-air flow sensor, a blow-off valve, which is vented to the atmosphere, may cause stumbling between shifts.
Can I run Nitrous Oxide on the Supra TT, even if I am already at BPU™ power levels?
Yes. Most people run 50-75 shot wet manifold systems. If you want to run a higher shot than this, you might want to consider a well-designed direct port system. I have seen as much as a 200-shot used on one of these systems, and an upgraded fuel system would be a must.
450hp just isn't enough, what can I do?
Ah the possibilities Basically you are only limited by your imagination, and your wallet. You know what they say, speed costs money, how fast do you want to go?
The real power lies in Single and Twin turbo upgrades, and the options are limitless. You can either build a mild motor that puts out 450 RWHP all day long with instant boost response, or a 1000+ RWHP monster.
Unfortunately, things start getting more difficult after simple BPU™ modifications. Modification becomes more than "bolt on Downpipe, gain 50hp". Things like tuning, parts selection, and matching combinations of parts become much more important. However, this is the case with ANY high HP car. Actually, even at exceptionally high power levels, the Supra TT is still easier to extract power from than almost any other performance car. But it should be kept in mind, that it wouldn’t be as simple as the BPU™ bolt-ons.
If you just want something that will toast that pesky Viper GTS. Then focus on a mild single turbo upgrade (T04S04, T60-1, SP57-SP61). Along with this, you should install a front mount intercooler, a fuel controller, fuel pulsation damper bypass and EGT gauge. This is assuming you have done all the BPU™ mods, plus BOV, EBC, Cam Gears. With tuning, and a few odds and ends, you should be able to pull 450-500 RWHP (490-580 crank HP) numbers while on a stock fuel system (assuming it is in great condition). This would be a total investment of approximately $6,700-$11,500 in engine/electronic components (also includes the proper gauges). If you already have the BPU™ mods or FMIC, etc., you will spend less than this. The difference in prices reflects the cost of higher end parts and addition of a HKS VPC to replace the restrictive stock MAF.
The next level would require a completely upgraded fuel system, and performance cams would be recommended, as well as further electronics (programmable engine management such as the AEM, or VPC/GCC/ECU combo, etc.). This would allow you to run much larger turbos and injectors. You can make it past the 700RWHP range without needing to replace the internals of the motor with stronger components, even at these power levels, if properly tuned and maintained you should retain a fair amount of reliability while still on the stock internals, as some people have eclipsed the 800RWHP level while still running stock bottom ends in their Supras. If you choose to go ahead and build up the bottom end, then the skies are the limit as far as power goes. Just make sure to have part selection, installation, and tuning done by competent and experienced persons. Although this should hold true at ANY level of modification.
Should I install a Turbo Timer?
Absolutely. Unless you don't mind sitting in your car while it idles down every single time you need to turn the car off. A Turbo timer keeps the engine running for a preset time once you turn off the ignition. So you can remove your keys, and lock up the car and not have to worry about it, it will shut off on it's own. This is important for the life of the turbos. If the turbos are not given time to cool down, it can overheat the oil and cause coking which will block oil flow to the turbos and damage bearings and cook seals.
How much is the Supra's power output affected by changes in ambient temperatures?
Very noticeably, just as with most turbo cars, the Supra Twin Turbo can be very temperature sensitive. Especially with the stock turbos and intercooler. On a BPU™ car, I would not be surprised to see a 10 percent reduction between 50-60deg temperatures, and 90deg plus temperatures
Will the stock clutch hold the power levels of a BPU™ car?
It depends on the condition and wear on the stock clutch. If it is in good condition, yes, it will hold the power, pretty well in fact, although you may experience clutch slip while at full boost in high gears such as 5th and 6th. If you drive vigorously, meaning you run at high boost frequently, then the life of the stocker will be GREATLY shortened. Be surprised if you see an extra 10,000 miles after BPU™.
Can I resurface my flywheel when replacing the clutch?
It is not recommended. Buy a new Toyota Flywheel.
Can I install a lightweight flywheel?
Yes, but be aware that they can create a lot of noise at idle, and can transmit more vibrations and shock to the expensive Getrag transmission.
Why is pulling the TRAC fuse beneficial over just turning it off with the switch on the center console?
Just pushing the "Trac Off" button only partially disables the Trac system. It disables the Trac throttle body and TRAC funtion through the ABS System (on 93.5-96 only), but not the Trac system's ignition timing retard function. Unplugging the Trac fuse eliminates both functions, as well as the 155mph speed limiter, which works through the trac system. The fuse can be found in the main fuse box on the driver’s side of the engine compartment. It must be noted that removing the fuse will cause the TRAC light to stay on, but you'll get used to it.
Will the TRAC system improve the cars performance?
NO. The Trac system was calibrated to improve traction in slippery conditions. It was not calibrated with performance in mind. When the Trac system senses a loss of traction, it comes on hard, cutting power drastically; this will do nothing but hurt performance. I also would not rely on the Trac system for providing stability at high speeds, if you were to loose control, it would be too slow and clumsy, and would more than likely hamper your efforts to regain control.
How can I remove the factory 155mph speed limiter?
Remove the fuse for the Trac system. The speed limiter works through the Trac throttle body.
What is the Supra TT's top speed with the Trac fuse removed?
There is some debate on this subject. There are rumors that 180 can be achieved. But by going with the numbers, 168-172mph in stock form seems possible.
What is the Supra TT's maximum theoretical top speed? Can it exceed 200mph with enough power?
Lets find out.
The Supra TT with the 6-speed has a stock engine redline of 6800rpm, and a 6th gear ratio of .79:1, with a rear axle ratio of 3.13:1. Now we multiply our 6th gear ratio times our rear axle ratio, and we find out our final gear ratio is 2.472:1. Now we divide 6800rpm by our total gear reduction of 2.472:1 and we find out our rear axles, and therefore wheels are spinning at 2751rpm at 6800 engine rpms.
Now we need to calculate our tire circumference. The rear tires section width it 255mm, and the sidewall's aspect ratio is .40, so our sidewalls are 102mm. Now, to convert this to inches, we divide this by 25.4, which equal’s 4.015 inches. Now multiply this by two, since we have two sidewalls making up the total diameter, and add the wheel diameter of 17", and we see a total diameter of 25.031 inches. Now to find out our circumference, we multiply that number times pi (3.14), and we find out the circumference is 78.59 inches, now divide that by 12 to convert to feet. And we get 6.549 feet total circumference.
Now multiply our tire's revolving speed, by the tire's outside circumference, and we find that the tire is covering 18,016 feet per minute, divide that by the 5280 feet in a mile, and we find we are covering 3.412 miles per minute, now multiply that by the 60 minutes in an hour, and we find we are traveling 204.7miles per hour @ 6800rpm in 6th gear. If the engines redline is increased to 7500rpm, which it often is, because of a higher flowing turbo. Then our maximum speed would be 225.8mph, given enough power of course.
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