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What is a turbo?
A turbo can significantly boost an engine's horsepower without significantly increasing its weight, which is the huge benefit that makes turbos so popular!

Turbochargers are a type of forced induction system. They compress the air flowing into the engine. The advantage of compressing the air is that it lets the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder. 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.
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. 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. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high.

Basics
One of the surest ways to get more power out of an engine is to increase the amount of air and fuel that it can burn. One way to do this is to add cylinders or make the current cylinders bigger. Sometimes these changes may not be feasible -- a turbo can be a simpler, more compact way to add power, especially for an aftermarket accessory.

Where the turbocharger is located in the car





Turbochargers allow an engine to burn more fuel and air by packing more into the existing cylinders. The typical boost provided by a turbocharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50 percent more air into the engine. Therefore, you would expect to get 50 percent more power. It's not perfectly efficient, so you might get a 30- to 40-percent improvement instead.

One cause of the inefficiency comes from the fact that the power to spin the turbine is not free. Having a turbine in the exhaust flow increases the restriction in the exhaust. This means that on the exhaust stroke, the engine has to push against a higher back-pressure. This subtracts a little bit of power from the cylinders that are firing at the same time.

A turbocharger helps at high altitudes, where the air is less dense. Normal engines will experience reduced power at high altitudes because for each stroke of the piston, the engine will get a smaller mass of air. A turbocharged engine may also have reduced power, but the reduction will be less dramatic because the thinner air is easier for the turbocharger to pump.
Older cars with carburetors automatically increase the fuel rate to match the increased airflow going into the cylinders. Modern cars with fuel injection will also do this to a point. The fuel-injection system relies on oxygen sensors in the exhaust to determine if the air-to-fuel ratio is correct, so these systems will automatically increase the fuel flow if a turbo is added.

If a turbocharger with too much boost is added to a fuel-injected car, the system may not provide enough fuel -- either the software programmed into the controller will not allow it, or the pump and injectors are not capable of supplying it. In this case, other modifications will have to be made to get the maximum benefit from the turbocharger.

Atricle from Turbo technics!
What is a Hybrid Turbo?

A hybrid turbocharger combines the quick boost response required at low engine revs, with the extra air-flow capacity needed for more power at higher revs - with excellent reliability.

Hybrid turbochargers are not a new idea. Turbo Technics started producing hybrids as long ago as 1985, and today continues to lead this specialised field. A language has even evolved to describe the components employed in hybrid turbos - words such as cut-back, 360°, screw-down and quick release.


But what does it all mean?

For most road going cars, a standard specification, good quality Service Exchange Turbocharger is sufficient. Hybrid turbos only become necessary when significant performance improvement is required, normally on a modified engine. Most hybrid turbochargers will look identical to standard units from the outside. The changes occur inside, by using different aerodynamic configurations, both in the compressor and turbine housings.

As a Garrett turbo dealer, Turbo Technics are in a unique position to choose from a comprehensive range of components. This allows our engineers to "blueprint" turbocharger components to achieve the desired characteristics needed for a particular application. Obviously there are limits, but this ability sets Turbo Technics apart from others in producing very effective hybrid turbos.

Most turbocharged engines respond well to increased boost pressure, but only if the engine is modified to capitalise on the change. The same can be said of turbochargers. A hybrid turbo on a standard engine may offer a small benefit, but will be more effective on a modified engine. Unfortunately, increasing the boost pressure also increases the internal loading within the turbocharger significantly. In order to compensate for this, a "screwed down" thrust bearing is sometimes used. This prevents the bearing from "lifting" at high load which can lead to oil starvation and component failure.

To continue up the hybrid ladder of performance, a "360°" thrust bearing is used. This is an entirely new bearing, manufactured by Turbo Technics, and originally developed for our competition customers, such as Ford Motorsport. It has a greater bearing contact face to withstand the high loads, which would otherwise destroy a standard bearing very quickly.

Turbo Technics will occasionally specify a "cut-back" shaft wheel. This is the main exhaust-driven turbine wheel inside the turbocharger. To limit its speed to acceptable, reliable levels, and to improve the airflow, the blades are "cut back". This is a very high precision machining operation, requiring highly accurate grinding and balancing. The Turbo Technics designed and manufactured VSR balancing machine ensures that exact limits are achieved every time, regardless of the vehicle to which the turbo will be fitted, from the humble Mondeo turbo diesel to a full works Group A' Escort Cosworth.

Another way in which a hybrid turbocharger can improve an engine’s performance is by improving response, or reducing turbo lag. By designing a more efficient turbocharger compatible with the engine's characteristics, Turbo Technics offer hybrid turbos which can transform a cars driveability.

The Turbo Technics range of hybrid turbochargers are also available throughout the UK Dealer Network. But beware of copies! Some imitation hybrids are cheaper, but when inspected are found to contain only standard internal components! Only Turbo Technics turbos carry an identification plate to guarantee the genuine article.

Hope this helps you all understand what all the turbo boys fuss about

good write up bud very useful!

Thanks for that scoop, I am not familiar with superchargers at all, never played with or driven one.

From what I have read, there are a few disadvantages of turbochargers - turbolag - complex bearings - intercooler etc. The traditional fan-belt driven superchargers also have problems, mostly the excessive amount of energy to drive the supercharger (up to 30%).

Why aren't electric superchargers more popular? With modern electronic control, driving it hard only when power demand is high, overall it could be very efficient and yet give more power to the wheels than either a turbo or a tradditional supercharger.

Whilst a tradditional supercharger takes an ovehead of 30% power away from the engine, a battery/alernator/motor combination could put the overhead to 0% when power demand is high (which can never be for extended periods because you run out of road), and charge the battery when lower demand is required. Overall the efficiency may not be as good as an intercooled turbo - but the maximum power will be much better.

The technology in a supercharge is much simpler - no complex bearing problems, no heat to disperse, no oil to complicate matters. So reliability should be much higher.

The complex bearing in a turbo are quarter/half and bad as a supercharger, namely a roots charger.

An electric supercharger will never conpete with a supercharger or even a turbo.