What turbocharger do, a turbocharger draws in air, compresses it and then feeds the pressurised air into your engine’s intake manifold. This dense, pressurised air then forcefully enters the combustion chamber when the piston makes a downward stroke. With more oxygen entering your engine at a quicker rate, you can burn more fuel. And when you burn more fuel, you make more power.
After the combustion cycle has completed, the hot waste gas exits the combustion chamber through an exhaust outlet. As the waste gas exits, it passes through the turbocharger and spins a compressor wheel. As the compressor wheel spins, it rotate turbine blade because both compressor and turbine are connected together.
Driven carefully, turbochargers do offer efficiency gains. But that efficiency can quickly disappear if you don’t drive with discipline. A turbocharged engine turns into a fuel-hog under hard acceleration, because the large volume of air being pumped into the cylinders must be matched by a larger volume of fuel.
To perform properly (and not destroy itself) an engine must mix air and fuel in a precise ratio. which ensures a chemically complete combustion event. If you introduce more fuel than necessary, you create a “rich” mixture, and part of the fuel passes through the engine unburnt, wasting gas and creating extra pollution. A lean mixture, on the other hand, saves fuel, but makes the engine run hotter.
High Engine knocking
Because it compresses the incoming air, the fuel injection system automatically adds more fuel to keep the mixture at the correct ratio. And this is where the problems begin. As the pressure in the combustion chambers rises, you run the risk of pre-ignition (commonly known as “knock”). Knocking is destructive (imagine millions of tiny grenades exploding inside your engine), but now a days by computerised engine control systems it is overcome.
Complex engine design
A turbocharged engine is not considered “naturally aspirated” because it uses a pump to force more air into the combustion chamber. By doing so, it allows automakers to employ a smaller engine. Now where is the problem?? so with a turbocharger, hard acceleration results in extremely high cylinder pressures. In response, the fuel system shoots in plenty of extra fuel – and there go your fuel savings. Also because of smaller engine size and having turbocharger, the no of extra components need to add so the design will be complex.
For example– In F-150 Ford pickup, now using turbocharged V-6 instead of the traditional V-8. Porsche just downsized the engine in 911 sports Porsche car from 3.8 litres to 3.0, but made it more powerful by adding a pair of turbochargers.
Higher maintenance cost
One more weak point could be maintenance
- Oil requirement: turbochargers get very hot and often tap into the engine’s oil supply. This calls for additional plumbing, and is more demanding on the engine oil. Superchargers typically do not require engine oil lubrication.
- A high quality synthetic oil is mandatory, as are frequent oil changes and synthetic oil is costly as compare to normal engine oil.
- Small rubber hoses, such as in the PCV system, need to be inspected for clogging, deterioration and if required then replaced periodically. Heat is the enemy of all plastic and rubber parts.
As others have noted, take good care of your small turbo engine, and it will take good care of you.
Excessive heat generated in engine because of turbo and lower engine size. so to reduce this excessive heat, a high quality of cooling are used. it increased total cost as well as frequency of maintenance.
Cost of turbocharged vehicle is higher than non-turbocharged vehicle
All the diesel engine powered cars on the market get turbochargers. With the emission norms becoming stringent, many modern petrol cars have started getting turbochargers. The turbocharger increases the power output of the engine enabling the manufacturers to squeeze out more power from even a smaller displacement engine. because of smaller engine size and having turbocharger, the no of extra components need to add so the design will be complex and also the overall vehicle cost become more the non-turbocharged vehicle.
this all content i took from different google sites and also as per my best experience .