Tiny turbo engines: good or bad?

Arif · Aug 08, 2020 07:00 AM

Engines are getting smaller and smaller by the day thanks to the help of an invention that dates all the way back to 1905 – the turbocharger. First used in aeroplanes with radial engines, the turbocharger was then used in big multi-cylinder diesel engines and finally found its way into production cars in the 1960s.

If our tax structure was different, we might see more LS swaps. Photo: Super Street

In Malaysia, turbochargers are a great way to have more power while avoiding the more expensive road tax for large capacity engines. We are about to see more small turbocharged engines in the not so distant future. The Nissan Almera and Honda City for example, only come with the 1.0 L turbo engine in Thailand. The Perodua D55L also might come with a 1.0 L turbo engine. One of the early 1.0 turbo engines would be the one in the Ford Fiesta Ecoboost.

The simple reason for the increase of small turbocharged engines is the increasingly strict emission requirements. Smaller engines produce less emissions. That’s it. While turbochargers might be synonymous with high performance, pairing them with small capacity engines is just a means to compensate for the reduced engine size. If two engines were of the same displacement, the one with a turbocharger will be able to produce more power.

While currently being used to meet with stricter emission regulations, turbochargers have always been a great performance upgrade for those who wanted to extract more power from the engine. 

The trend of factory-fitted turbochargers in small engines creates dividing opinions. Some feel that turbochargers are harder to maintain and may incur higher maintenance cost. Others on the other hand, are more receptive towards the idea. Are tiny turbo engines good or bad? Let’s dive in…

Q: First, what is a turbocharger?

A: A turbocharger is a device that forces more compressed air into the intake port of the engine.

Q: How does a turbocharger work?

A: The exhaust gas spins the turbine. The turbine spins the compressor. The compressor forces more compressed air into the engine. That's it.

Q: Does the exhaust gas get pumped back into the engine?

A: No. The energy of the exhaust gas is what moves the turbine of the turbocharger. The turbine drives the compressor of the turbocharger. No exhaust gas is pumped into the engine.

Q: Doesn’t a supercharger do the same thing?

A: Yes. The difference is, turbochargers are driven by the exhaust gas while superchargers are driven by the crankshaft itself (gear driven or belt driven)

Mazda's SkyActiv-X is one of the few engines that is factory-fitted with a roots type supercharger.

Q: What are the benefits of turbocharging?

A: More POWER. That is the most obvious benefit a turbocharger can give.

A turbocharger makes full use of the exhaust gas that would otherwise be expelled into the atmosphere.

Turbochargers allow manufacturers to use smaller-sized turbo engines to produce a higher power output than a naturally-aspirated (NA) larger-capacity engine. Using a smaller engine translates to lower emissions.

The 1.5 Turbo Honda Civic produces 173 PS and 220 Nm. The NA 1.8 version produces 141 PS and 174 Nm

How is more power achieved by using a turbocharger?

A denser air-fuel mixture is provided to the engine. More oxygen and fuel are burned per unit time. Denser air into the intake is a good thing. That’s why cold air intakes are also a good thing. Cold air is denser.

Remember this from science class? Photo: boldmethod.com

A: But turbochargers can reach temperatures up to 1000°C. How is that good?

A: It’s not good. That’s why cars with turbochargers have intercoolers. They allow for higher intake air-charge density. Without an intercooler, hot air is pumped into the engine. Not good.

Hood scoops indicate the presence of a top-mount intercooler.

Q: If turbochargers are so good, why aren’t more cars being fitted with them from the factory?

A: They are. It just depends where you live. Regions with stricter emissions regulations are seeing more and more turbocharged small engines in regular cars.

For average daily driving with small city cars, turbochargers are not that important. Unless there are strict emission regulations, a turbocharger is not needed for a small city car.

In other applications, turbochargers have shown to be useful to extract more performance from an engine.

Q: Do turbocharged engines require more maintenance?

A: Yes. 

Q: Why?

A: Turbochargers require lubrication too. The same lubricant that circulates the engine is used to lubricate the turbocharger too. Turbochargers can reach temperatures of up to 1000°C and deteriorate the engine lubricant much faster.

It doesn't get this hot in your turbocharged Proton X70. Photo : autoexpert

The bearings in the turbocharger can also go bad over time.

Q: Are tiny engines good?

A: If you had two engines that were both naturally aspirated (NA), the smaller-capacity engine would have less power. Tiny engines also tend to be three-cylinder engines, which usually vibrate more than a 4-cylinder engine. No matter how advanced the technology gets, the simple physics is that odd-number-cylinder engines are harder to balance.

Q: Are tiny turbo engines good then?

A: To reduce emissions, yes. It is a matter of smaller-displacement engines producing less emissions. The lacking power of the small engine is compensated by the turbocharger. If paired with a good transmission, the driving experience can be pleasant.

Whether or not the benefits of the turbocharger outweigh the added maintenance required is really up to personal preference.

Summary

1. Turbochargers are great for extracting more power from an engine.

2. Small turbocharged engines are great for reducing pollutant emissions.

3. Tiny turbo engines are usually 3-cylinder engines. 3-cylinder engines vibrate more than 4-cylinder engines.

4. The reason manufacturers are producing more regular cars with turbocharged engines is just to comply with stricter emission standards

5. Turbocharged engines do require slightly more maintenance compared to their NA counterpart.


 

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