Section Contents:- Turbochargers start producing boost only above a certain rpm (depending on the size of the turbo) because they are powered by the movement of exhaust gases; without an appropriate exhaust gas velocity, they logically cannot force air into the engine.(More...)
- Turbocharger kits, supercharger kits, blow-off valves, intercoolers, boost controllers, turbo timers, wastegates, and more.(More...)
Turbochargers start producing boost only above a certain rpm (depending on the size of the turbo) because they are powered by the movement of exhaust gases; without an appropriate exhaust gas velocity, they logically cannot force air into the engine. [2] Turbocharger starts producing boost only above a certain rpm due to a lack of exhaust gas volume to overcome inertia of rest of turbo propeller. This results in a rapid and nonlinear rise in torque, and will reduce the usable power band of the engine.
[2] Using turbochargers to gain performance without a large gain in weight was very appealing to the Japanese factories in the 1980s. The first example of a turbocharged bike is the 1978 Kawasaki Z1R TC. It used a Rayjay ATP turbo kit to build 5lb (2.3kg) of boost, bringing power up from ~90 hp to ~105 hp. It was only marginally faster than the standard model (11 lb and 145hp (108kW) with a modified wastegate).
[2] Some car makers use water cooled turbochargers for added bearing life. This can also account for why many tuners upgrade their standard journal bearing turbos (such as a T25) which use a 270 degree thrust bearing and a brass journal bearing which has only 3 oil passages, to a 360 degree bearing which has a beefier thrust bearing and washer having 6 oil passages to enable better flow, response and cooling efficiency.
[2] Turbochargers with foil bearings are in development which eliminates the need for bearing cooling or oil delivery systems, thereby eliminating the most common cause of failure, while also significantly reducing turbo lag.
[2] Variable-nozzle turbochargers (discussed above) eliminate lag. Another common method of equalizing turbo lag is to have the turbine wheel "clipped", or to reduce the surface area of the turbine wheel's rotating blades.
[2] In internal combustion engines a turbocharger is a turbine driven forced induction compressor powered by pressure from the engine's exhaust gas. This is in contrast to a supercharger, which is mechanically driven by the engine's crankshaft via a belt.
[2] The demands of the war led to constant advances in turbocharger technology, particularly in the area of materials. This area of study eventually crossed over in to the development of early gas turbine engines. Those early turbine engines were little more than a very large turbocharger with the compressor and turbine connected by a number of combustion chambers.
[2] Often the same basic turbocharger assembly will be available from the manufacturer with multiple AR choices for the turbine housing and sometimes the compressor cover as well. This allows the designer of the engine system to tailor the compromises between performance, response, and efficiency to application or preference. Both housings resemble snail shells, and thus turbochargers are sometimes referred to in slang as snails.
[2] The turbocharger has four main components. The turbine and impeller /compressor wheels are each contained within their own folded conical housing on opposite sides of the third component, the center housing/hub rotating assembly (CHRA). The housings fitted around the compressor impeller and turbine collect and direct the gas flow through the wheels as they spin.
[2] A turbocharger consists of a turbine and a compressor linked by a shared axle.
[2] Although adding a turbocharger itself does not save fuel, it will allow a vehicle to use a smaller engine while achieving power levels of a much larger engine, while attaining near normal fuel economy while off boost/cruising.
[2] To minimise the effects of turbo-lag some high end vehicles use two turbochargers in series, one is somewhat smaller and spins up more quickly and thus cuts in at relatively low engine speed and improves low end torque whereas the other cuts in at high engine speeds. This creates a smoother and higher torque curve and thus makes the vehicle faster and easier to control.
[2] Using a small turbocharger will give quick response and low lag at low to mid RPMs, but can choke the engine on the exhaust side and generate huge amounts of pumping-related heat on the intake side as RPMs rise.
[2] Conversely on light loads or at low RPM a turbocharger supplies less boost and the engine is less efficient than a supercharged engine.
[2] Because boost is related to engine load, the turbocharger only runs at full capacity when the engine is under load.
[2] Newer turbocharger and engine developments have caused boost thresholds to steadily decline to where day-to-day use feels perfectly natural.
[2] Since a turbocharger increases the specific horsepower output of an engine, the engine will also produce increased amounts of heat. This can sometimes be a problem when fitting a turbocharger to a motor that was not designed to cope with high heat loads. It is another form of cooling that has the largest impact on fuel efficiency: charge cooling.
[2] Superchargers and turbochargers use output energy from an engine to achieve a net gain, which must be provided from some of the engine's total output.
[2] Turbochargers are used in reciprocating aircraft engines which are designed for high altitude use.
[2] Turbochargers were first used in production aircraft engines in the 1930s before World War II.
[2] If a turbocharger that is too large is used it reduces throttle response as it builds up boost slowly. Doing this may result in more peak power.
[2] Gasoline engines often require extensive modification for turbocharging. Diesel engines have a narrower band of engine speeds at which they operate, thus making the operating characteristics of the turbocharger over that "rev range" less of a compromise than on a gasoline-powered engine.
[2] Complexity. Further to cost, turbochargers require numerous additional systems if they are not to damage an engine.
[2] The first production turbocharged automobile engines came from General Motors in 1962. The A-body Oldsmobile Cutlass Jetfire and Chevrolet Corvair Monza Spyder were both fitted with turbochargers.
[2] A pair of turbochargers mounted to an Inline 6 engine ( 2JZ-GTE from a MkIV Toyota Supra ) in a dragster.
[2] The turbocharger was invented by Swiss engineer Alfred B"chi. His patent for a turbo charger was applied for use in 1905.
[2] Race cars often utilize an Anti-Lag System to completely eliminate lag at the cost of reduced turbocharger life. On modern diesel engines, this problem is virtually eliminated by utilizing a variable geometry turbocharger.
[2] Maserati in 1980 was the first to introduce twin or bi-turbo Maserati Biturbo. Renault however gave another step and installed a turbocharger to the smallest and lightest car they had, the R5, making it the first Supermini automobile with a turbocharger in year 1980. This gave the car about 160bhp (120kW) in street form and up to 300+ in race setup, which was extraordinary output for a 1400 cc motor.
[2] In either case, an automatic or manually-controlled wastegate is used to vary the turbocharger output according to operating conditions.
[2] Due to a lack of sufficient materials as well as funding, initial progress was slow. Turbochargers were used extensively in military aircraft during World War II to enable them to fly very fast at very high altitudes.
[2] One way to take advantage of the different operating regimes of the two types of supercharger is sequential turbocharging, which uses a small turbocharger at low RPMs and a larger one at high RPMs.
[2] Electrical boosting ("E-boosting") is a new technology under development; it uses a high speed electrical motor to drive the turbocharger to speed before exhaust gases are available, e.g. from a stop-light.
[2] In the late 1970s, Ford and GM looked to the turbocharger to gain power, without sacrificing fuel consumption, during not only the emissions crunch of the federal government but also a gas shortage.
[2] As turbocharger technology improved, it became possible to produce turbocharged engines with a smoother, more predictable but just as effective power delivery.
[2] One of the first applications of a turbocharger to a non-Diesel engine came when General Electric engineer Sanford Moss attached a turbo to a V12 Liberty aircraft engine.
[2] Boost refers to the increase in manifold pressure that is generated by the turbocharger in the intake path or specifically intake manifold that exceeds normal atmospheric pressure. This is also the level of boost as shown on a pressure gauge, usually in bar, psi or possibly kPa. This is representative of the extra air pressure that is achieved over what would be achieved without the forced induction.
[2] Because the turbocharger increases the pressure at the point where air is entering the cylinder, and the amount of air brought into the cylinder is largely a function of time and pressure difference, more air will be forced in as the inlet manifold pressure increases.
[2] Turbochargers also provide more direct fuel savings when compared to a supercharger.
[2] Lastly, the efficiency of the turbocharger itself can have an impact on fuel efficiency.
[2] Heavily modifying OEM turbocharger systems also require extensive upgrades that in most cases requires most (if not all) of the original components to be replaced.
[2] The oil is usually taken from the engine-oil circuit. Some turbochargers use incredibly precise ball bearings that offer less friction than a fluid bearing but these are also suspended in fluid-dampened cavities.
[2] Diesel ships and locomotives with turbochargers began appearing in the 1920s.
[2] To manage the upper-deck air pressure, the turbocharger's exhaust gas flow is regulated with a wastegate that bypasses excess exhaust gas entering the turbocharger's turbine. This regulates the rotational speed of the turbine and the output of the compressor.
[2] As the turbocharger's output flow volume exceeds the engine's volumetric flow, air pressure in the intake system begins to build, often called boost.
[2] A turbocharged engine produces more power overall than the same engine without the charging. This can significantly improve the power-to-weight ratio for the engine (see How Horsepower Works How Horsepower Works for details). In order to achieve this boost, the turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins an air pump.
[3] The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) -- that's about 30 times faster than most car engines can go.
[3] In this article, we'll learn how a turbocharger increases the power output of an engine while surviving extreme operating conditions. We'll also learn how wastegates, ceramic turbine blades and ball bearings ball bearings help turbochargers do their job even better.
[3] Turbochargers are a type of forced induction system. They compress the air flowing into the engine (see How Car Engines Work How Car Engines Work for a description of airflow in a normal engine).
[3] In the Engine Performance section, learn about horsepower, carburetors, the difference between turbochargers and superchargers and even how nitrous oxide boosts engine performance.
[3] The typical boost provided by a turbocharger is 6 to 8 pounds per square inch (psi).
[3] This is a high quality cast iron manifold for all 12V VR6 applications, that allows mounting a standard T4 flange (tangential housing) turbocharger.
[3] When people talk about race cars race cars or high-performance sports cars, the topic of turbochargers usually comes up.
[3] With air being pumped into the cylinders under pressure by the turbocharger, and then being further compressed by the piston (see How Car Engines Work
How Car Engines Work for a demonstration), there is more danger of knock
knock.
[4] There are many tradeoffs involved in designing a turbocharger for an engine. In the next section, we'll look at some of these compromises and see how they affect performance.
[4] In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing. This type of bearing supports the shaft on a thin layer of oil that is constantly pumped around the shaft. This serves two purposes: It cools the shaft and some of the other turbocharger parts, and it allows the shaft to spin without much friction.
[4] Cars with turbochargers often need to run on higher octane
octane fuel to avoid knock.
[4] 
Turbocharger kits, supercharger kits, blow-off valves, intercoolers, boost controllers, turbo timers, wastegates, and more. [5] Got a question about turbocharger kits? Get answers to some of the more common ones.
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