Explain car engines to me?

So I'm reaching the point in my life where I'm looking to buy my own car. This is 2 different trims from the same model of car but I don't fully understand the difference. I know horsepower is important for acceleration and torque is important for work but how does the turbo come in? I do a lot of highway driving so I need a car that has good step to get up to speed and switch lanes and what not. 

I am also coming from a car that is 3.5L V6 272hp so I'm used to a bit more power. Both models of these cars have the features I want, I just don't understand the engines. Thanks!

Attachment image

6 Answers

  • 2 months ago
    Favourite answer

    The 2.5L in this case is the "base" model engine, the 1.6 Turbo is the "optional" engine. (Hyundai Sonata or Kia Optima?)  The 1.6T will feel a little more punchy than the 2.5 from about 2000RPM to 5000RPM due to how the turbo spools up and provides boost in that RPM range.  At RPM above 5000, the 2.5 will be faster when comparing these 2 engines.

    Big picture, the 2 engines won't feel THAT much different compared to one another, and neither will likely feel as powerful as the V6 in your current car unless your current car is a heavy CUV/SUV or something.  If you really want to know more about interpreting the engine specs, then read on... 

    The HP rating listed is the PEAK amount of power the engine can produce.  That peak power is only made at the listed RPM.  (At every other RPM the engine makes less power than that rating)  So the 2.5L engine makes more PEAK power than the 1.6 Turbo, but you'd have to be revving both engines at 5500RPM for the 2.5 to pull noticeably harder than the 1.6T. 

    The Torque rating is PEAK TORQUE produced.  What you feel when you stomp the gas pedal is POWER pulling you along, always.  You don't "feel" torque necessarily, but since torque is directly related to power output by the equation:

    Horsepower = (Torque X RPM) / 5252

    ...then if one engine generates more torque at a given RPM than the other engine at that same RPM, the engine producing more torque must also be generating more power at that same RPM. 

    So for example from the equation above, if you plug in the torque each engine produces at 4000RPM from the specs listed, the 1.6T will be making 149hp at 4000RPM whereas the 2.5 will only make 138hp at 4000RPM.  Which is why the 1.6T will feel a little "punchier" at RPM below ~5000 or so.

    Hopefully that makes some sense.  End of the day, the 1.6T will feel a little more powerful at the RPM more commonly used in daily driving.  Whether that difference is enough to justify paying more for the 1.6T engine option is entirely up to you.  Good luck and enjoy the new car!


  • F
    Lv 6
    2 months ago

    Myths about turbos:

    1.They are unreliable. 

    No. Virtually every lorry on the road has a turbo (diesel) , they do a million miles no problems. Sometimes people turbo charge engines that weren’t designed for it and they blow up . The turbo hadn’t failed.

    2.Oil changes are more frequent . 

    Only for extremely high powered sports cars. The correct oil is however crucial.

    3.You don’t have to wait forever for it to cool down. Again high performance cars when they have been driven hard but in normal use , no need. ( I’ve had 11 turbo cars , never a failure )

    4. They are more economical . Yes and no. In official tests they come out well and manufacturers are happy to advertise these figures. The engine is rarely on boost and do the smaller engine is more economical. You also benefit from lower taxes in most countries.

    In practice , the smaller engine had to work harder in real life and is on boost more, resulting in higher than expected fuel consumption. A good example is the Fiat 500. Standard engine is a 4 cylinder 1.2. Option is a 2 cylinder 0.9 litre turbo. On paper the small engine is more powerful and more than 10mpg better. In practice , you have to thrash the 2 cylinder all the time even in such a small car, resulting in great fun but 10mpg worse than the other engine and about 20 mpg less than expected.

  • 2 months ago

    A turbo will squeeze more power out of an engine. That also adds stress, more than a non-turbo engine as it is called to work harder, but the turbo boost is not constant. It is an on-demand function as you floor the gas pedal. Turbos do require more frequent oil changes and a cool down period before shutting down the engine after each drive. A turbo charger also is just one more very expensive item to maintain. The particular car you're looking at has stats I don't like, for instance, the bigger engine has a very high compression ratio that would require premium fuel. I have a hard time believing the smaller engine is going to make 180 HP at 1500 rpm, but if it does that is one hard working sob. More important though for you to consider is the reliability of the car whatever engine it comes with.

  • Anonymous
    2 months ago

    I would get the 2.5L if you care about reliability. Turbos add more complexity to an engine and more stuff to break. 

  • What do you think of the answers? You can sign in to give your opinion on the answer.
  • Jay P
    Lv 7
    2 months ago

    Generally speaking, if you're comparing a naturally aspirated ( N/A ) 4 cylinder to a turbocharged 4 cylinder, the torque curve of the N/A engine tends to be peaky while the turbo engine will be flatter, with peak torque reached earlier within the rev-range.

    Of the two engines in the example, the N/A, with its displacement advantage, does produce more HP, but at a higher RPM.  the turbo engine, on the other hand, produces more torque, and within a far more useable RPM range ( between 1500 through 4500 RPM ).

    For everyday driving, the turbo engine will feel more peppy.  The N/A engine, in comparison, will require you to keep the RPM's higher to achieve similar performance. 

  • rodcom
    Lv 6
    2 months ago

    A turbo enables you to get more power from a smaller engine when it revs up, but is still economical at lower speeds which you would expect from a smaller engine.  Once the engine spins up fast enough, it uses the exhaust gases to spin the turbo up, which is really just a big fan compressing fresh air.  This air is cooled and forced into the intake, increasing the amount of air entering the cylinder.  This enables more fuel to be burned and a higher compression in the cylinder when it ignites, giving you more power.  This is really good for acceleration.  Once you are at cruising speeds and not using as much power, the turbo spins down and your car is in a more economical mode again.  In addition to getting more power out of a smaller engine, a smaller engine means less weight, so you need less power to move the vehicle.  That is called power to weight ratio..  As for torque, that is more important when towing, not so much for every day driving.  A transmission converts hp to torque.  That is why hp is only meaningful when the gear ratio matches what you want to do with it.  272 hp in a car is pretty fast because they have light weight and the gearing to get you up to speed fast.

    Now put that 272 hp in a pickup truck, and the extra weight, combined with different gearing will make it much slower, but you will also be able to tow 6000 lbs.

    The CVVT and CVVD are different valve technologies to vary when and how long, and how much the valves are opened to maximize fuel economy and power.  The 1.6 with CVVD is supposed to be pretty sophisticated with good power, economy and emissions.  It is new technology though, so I cannot speak for its long term reliability.  The 2.5 is naturally aspirated but also an updated engine.  That is the one I think that I would lean toward for my own personal choice, but I also keep cars around for well over 200,000 miles, so I like less complex things to go wrong in the long run.  If you are one who gets a new car every 5 years, then I would likely try the 1.6 since it has a good warranty, assuming the prices are also similar.

Still have questions? Get answers by asking now.