You’ve heard the saying, your mileage may vary?
Well, there’s a new variable you ought to take into account when you go shopping for a new car. You might call it the Turbo Tax. It’s paid two ways – up front and down the road.
And it’s becoming harder to avoid either tax, because about a third of all new cars on the market come standard with a turbocharged engine. Within the next few years, it will be tough to buy any new car without a turbocharged engine.
But what is a turbo? Why are turbos being put under the hoods of so many new cars?
And why is it . . . taxing?
A turbo is a compressor. It pressurizes the incoming air that would – ordinarily – be sucked into the engine’s cylinders very much in the same manner that we draw in a breath. Pressurized air is forced into the engine’s cylinders; this increases cylinder pressure and creates a more powerful explosion when the spark plug fires.
So, it’s basically a power-enhancer.
Turbos were rare – even exotic – as recently as a decade ago. They were added to already powerful engines in high-performance cars to make them deliver even higher-performance. This makes perfect sense when the object is to go faster – and paying extra is understood to be the price of admission. People who buy high-performance cars are not buying them for reasons of economy.
But now turbos are being used for exactly that reason.
Well, so we’re told.
Reality tells another story.
And the main reason for this is that it’s becoming hard to put engines larger than very small fours in most new cars. Not physically hard. But politically, very hard.
Turbos are bolted to the small fours to make up for the smallness of these engines. To make them capable of producing the power and delivering performance comparable to that produced by the larger (six cylinder) engines they replaced.
But why not just keep the larger engine, in that case?
Well, it would make sense. But this isn’t about making sense. It is about making the government happy – while also keeping customers happy.
Hence turbocharged cars.
The government-downsized engines have the potential to use less gas – when the turbo isn’t boosting them. This helps the car companies meet the government’s fuel efficiency mandates – or at least, helps them avoid the government’s fines for not meeting them.
And when the turbo is boosting, it makes buyers – who expect their car to accelerate when they press on the accelerator pedal – not miss the larger engines which made equivalent power without resorting to turbo-boosting.
But it’s not without cost – the Turbo Tax.
It’s a layered – and hidden tax.
You pay more for the turbo-engined car, to begin with. Because in addition to buying the engine, you’re also buying the turbo and all the turbo-related parts, usually including an intercooler (basically, a radiator for the turbo) and always including a specialized exhaust system – because the turbo’s boost is produced by exhaust gas pressure. There’s no getting around the extra parts – which costs extra money.
If you compare the sticker price of a given car model that was available a year or two ago without a turbocharged engine with what the same car costs today with a turbocharged engine, you’ll discover the sticker price has increased significantly.
Here’s an example:
The current/2019 VW Jetta is basically the same car as the 2015 Jetta, except for the fact that the new one comes standard with a 1.4 liter turbocharged four cylinder engine while the 2015 came standard with a larger 2.0 liter engine without a turbo.
The base price of the 2015 Jetta was $16,215. The current Jetta stickers for $18,545. Some of the difference in price can be discounted as inflation; that $16,215 in 2015 dollars is actually $17,514 in today’s dollars. But that still leaves a balance due – payable by you – of $1,031 for the turbocharged “upgrade.”
You do get more power – 147 hp for the new one vs. 115 for the no-turbo 2.0 engine in the 2015. But you’re not getting it for free – and the mileage gain is offset (in terms of economy) by the extra grand-plus you had to pay up front for the car.
And then there’s the hidden tax.
Most of these turbo’d small-engined cars at least “recommend” that premium fuel be used. You don’t have to use it, in the sense that you won’t hurt the engine if you use regular. But if you don’t use premium, the stated best-case mileage (and power/performance) will be less than advertised. The reason is simple.
Or rather, mechanical.
Increased cylinder pressure requires higher-octane fuel, which is more resistant to spontaneous combustion from heat and pressure than lower-octane gas. Use of lower-octane fuel has to be dealt with by reducing cylinder pressure (less boost) to avoid spontaneous combustion – premature ignition – which in the old days resulted in engine knock and – if you kept at it – a damaged engine.
Today’s cars turbo’d cars can control cylinder pressure electronically – by dumping open the wastegate – to bleed off boost .
This doesn’t don’t damage the engine; you just get a less fuel-efficient and powerful engine.
The ECU – the brain box that runs the show – takes notice of the lower octane fuel, dials back the boost, ignition timing and so on to prevent spontaneous combustion and engine knock. But you pay the tax in the form of not-quite-what-was-advertised mileage and reduced power/performance.
Or, you can pay the extra 40 cents or so per gallon at the pump, for the premium fuel.
Either way, you’ll pay.
. . .
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