Like why does it take mine like 15 seconds to get up to 60mph and other cars they do it in 5 or 8 seconds? They’re faster away from the traffic lights too.
Their engines work fundamentally the same like the same combustion process so what makes slow cars and what makes faster ones?
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Car makers can spend more money on more expensive engine parts to make them have more power. Cars that have more power also use more fuel, which is an important consideration when buying a car. At some point you you can make it even MORE powerful but it’s also less reliable because of the added stress.
Makers build cars with just 1 or 2 engine choices based on how much money they think people will be willing to pay for the car as a whole, how reliable people expect it to be, and how much fuel people expect it to use. Since few people are willing to pay double for an economy car that accellerates really fast and uses a lot of gas they don’t bother putting more expensive engines in them (with some rare exeptions). You can apply this logic to all cars, the makers strike a balance between cost, fuel efficiency and longevity, based on their target buyers. On the other end of the spectrum you can get a Lamborghini that goes really fast, but uses a ton of gas and also needs very expensive maintenance very frequently, because the people that buy those sorts of cars are OK with that.
There are lots of ways to build an engine… small, big, higher compression ratios, more or fewer cylinders, etc. An engine designed for power will consume more fuel than a smaller one designed for economy even at the same speed. So for small, cheap, “efficient” cars you get the smaller engine, and hence the weaker acceleration.
There are other possibilities… like the gear ratios and how many are available, and the programming of the car computer. Eco and Performance (aka Sport) modes are absolutely doable, and if your car happens to have these options, make sure they are set how you want them. Not to mention the driver operating the car correctly… more so in a manual than an automatic, but it is still possible to do it wrong.
You eat the same food as Usain Bolt and fundamentally your muscles work the same way, can you run as fast as him?
That should tell you that there is something incorrect with your reasoning. Some cars are built to go fast and others are not – generally because they are probably designed for other functions.
There are good answers here, I want to add a few main things when considering speed/acceleration like you’re talking about. 1st off the weight of the vehicle plays a huge part, generally performance cars are using materials like aluminum and carbon fiber to reduce weight where they can. Second is drivetrain (motor transmission axles) these can all be made lighter/ more durable / more efficient. 3rd I’ll use an example I have a 1989 325i it has a 2.5L 6 cylinder engine. The sportier version of my car the M3 has a 2.3L 4 cylinder engine. You might think that because my car has a larger engine it will be faster but because of those points I made earlier such as lighter weight, quicker shifts, or more efficient parts it is actually much much faster than the 2.5L
A car is a collection of thousands of choices to come to what you think the consumer wants most, a few of those are going to impact direct performance.
At it’s base, you want a car that can get to the acceptable safe speed to go on all roads, so it needs to be able to hit highway speeds without stressing the engine too much. You can do this with a big complicated gearbox that has a huge amount of gears (like a truck), or a smaller lighter one that might only have as low as 4 gears + R, but you’ll need a better engine to compensate.
Then you want that engine (plus the earlier gears), to be able to safely accelerate enough to not hold you and others up too much. This can be achieved by a shorter ratio and more shifting early, or a more powerful engine.
Then you also have to consider weight of the componenets, which is going to impact the previous two as well. You can make a full cast iron setup with high tolerances (more margin for error), which will make everything cheaper (for you), but could mean things are worse in other factors. Alternatively you can make things out of titanium and magnesium, which are extremely light, but very difficult to work with and can be dangerous if not considered properly. The middleground being Aluminum, which is light, cheap, and easy to work with, but not the strongest, so you have to work with tolerances you wouldn’t have to with iron or steel.
In addition to just what goes to the wheels, you also have to consider part of the engine’s power is either lost to be more fuel efficient, or going towards internal features and modcons like AC and more electrical gizmos. These also add weight, and are one of the biggest things that have meant modern cars need more horse power than older cars. Everything is (relatively) sound proof, AC’d, heated, fully electric (windows, seats etc.), a full entertainment system, power steering, fancier gearboxes, fancier suspension, more storage space, the list goes on.
Now to the real meat of it, as all of this increases, you need exponentially more power to achieve the same speed. This also has to fit within the safety and emission standards of the modern world. Taking this into account, some car makers choose to aim at the lower end of the price demographic, and make compromises they think are worth it, without skimping in others that they think will make consumers choose theirs over their competitors. These days it’s most common to provide the cabin modernities as standard or almost standard (leather seats and/or trim upgrade). Instead choosing to release multiple skews of the mechanicals instead, so you can get the same car with a 1L, 1.6L, 2L, 1.8L Turbo, 5 speed, 6 speed, auto, etc. as those can be mixed and matched between cars more easily.
> Their engines work fundamentally the same like the same combustion process so what makes slow cars and what makes faster ones?
What makes a high powered torch more powerful than a cigarette lighter? They both burn gas to produce flames, right?
To take a slightly simplistic view, it’s the same thing in a car engine. If an engine is built to be able to suck in more air and gasoline and burn it, then it can output more power. There’s more complicated engineering things that go on to get more performance (power-to-weight, tuning, gearing, mechanical efficiency, etc.), but at the most basic level this explains why you should expect a 6.2L Corvette Stingray to outrun a 1.9L Ford Fiesta.
Imagine your car’s engine is a smaller four cylinder engine, and the other car’s engine has six cylinders and they are also larger.
Now imagine that each in cylinder is a human arm that is responsible for pushing on a hand crank to turn the engine shaft to the wheels. (The arms would be an analogy for the piston.) In your car you’ve got four skinny arms, and in the other car there are six muscular arms. (The difference in strength is due to a larger cylinder bejng able to accept more fuel and make a bigger, more powerful explosion, which we are representing by bigger muscles in our imagination.)
Let’s assume that the two cars weigh the same and have the same gears. Now, both engines are being asked to get the cars moving by pushing on those hand cranks. Your foot pushes on the gas pedal all the way which causes these arms to push as hard as they can. The four arms in your car work together but there’s a limit to how hard they can push the cranks. So your car speeds up slowly. In the other car, six muscular arms can get the car moving much more easily.
There are other variables too, and you can improve the power of four cylinders considerably, but cylinder volume matters a lot.
There are TONs of things that make a car faster, but the main idea is that engines are a glorified air pump. The more air you can get into the engine, means you can send more fuel and in turn, get more power. This can be done through many different ways, for example a small 2 liter 4 cylinder engine, will not be able to get as much air into it, as a 7.3 liter 8 cylinder engine that you would find in a truck. There are also other ways to get air in like “forced induction”. Forced induction cars use turbochargers or superchargers to force more air into the engine. Superchargers for example are air compressors mounted on top of the engine that is powered by a belt that is connected to the engine, so as the engine starts rotating faster, it powers the air compressor which pushes more air into the engine to create bigger explosions and more power. That’s also why something like a truck or a high power sports car will use significantly more fuel than a tiny commuter car.
A horse can pull a cart easier than a goat. Both have legs, but a horse is bigger with more muscle.
The engine power may differ a lot. A car with 400 kW engine will faster accelerate than one with only 50 kW. It’s all about the power/weight ratio. And today we have electric vehicles where the engines do not need gear boxes and deliver the same force at any speed.
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