what makes cars hp more than others? Like why can’t all cars be 800hp like a challenger for example
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Fuel economy and cost are the main reason. 800hp challengers eat through gas and require more durable, more expensive parts. Lots of people don’t want 800hp so they want to save the money
While fuel economy is the reason most people don’t want something with more horsepower than necessary, the difference between engines is the power in and how well that is converted to a force, and how efficiently that force can be turned into velocity.
So you may have an engine with 4 cylinders and can take in power (fuel) and convert that to force x, causing it move at a velocity of y. So your HP would x*y.
But then let’s say you have a 6 cylinder engine. This takes in power(fuel) converting it to 1.5x lbs of force and moves your car 1.33y. So your HP Then is (1.5x)*(1.33y).
Does that answer your question?
Power is the product of torque and speed.
Speed limits are dependent on material properties of the engine, as well as the ignition system (i.e. 4000 RPM is considered fast for a diesel, but is barely a jog for a spark ignited engine).
Torque is fundamentally determined by how much air the engine can ingest per cycle (i.e. displacement), as well as how much the air mixture is compressed before combustion occurs (i.e. compression ratio), and obviously the number of cylinders. Both factors are also affected by aspiration (i.e. turbocharging, supercharging or natural aspiration). There’s also fueling to consider, but realistically fuel delivery is a solved problem in engine controls; it’s comparatively easy to provide more fuel than you actual need due to how well-developed fuel injection technology is.
Smaller engines tend to be more efficient for automotive applications. You don’t need 800 hp to get to 60 mph in a timely manner; 80 hp is perfectly sufficient, and it’ll cost way less to make an engine that can only hit 80 hp. But 80 hp isn’t as much fun as 800.
The physics behind engine power and fuel economy are well understood.
At a basic level if you want more power you need to burn more gas and air. You need to make the engine bigger, and spin faster. That and make it more efficient, less friction, less weight, etc.
The problem is that more powerful engines aren’t nearly as fuel efficient.
Since the average person doesn’t need 800hp to drive to the store it makes a lot more sense to build cars in the 100-200 hp range where you get enough power to do what you need to do while saving gas. The engines are also cheaper, lighter, and last longer.
Cars have “small” engines because of racing rules. In the early days cars had LARGE engines which produced phenomenal amounts of torque and power.
However, to win the next race you just built a bigger engine. That was considered unsporting and so they restricted engine size to 1,500cc. This caused an explosion in engine development and power trains.
All cars could be like a Challenger if wanted but why?
The giant VERY powerful engines were quite happy to cruise at 60mp at 200- 300rpm Whereas your small engine needs 2,000+rpm. The fuel consumption is comparable.
so 800hp is only useful for…accelerating very quickly…and…and…well..and…????
For another angle if you ever have a chance to drive a 500+ hp car you’ll quickly realize it’s simply not necessary. 800 hp is very very powerful.
>what makes cars hp more than others?
Horsepower is only an rating of the power put out by the engine, while it’s sitting on a concrete pad. It completely ignores weight, and what really determines your vechicle’s overall performance is its power to weight ratio.
>Like why can’t all cars be 800hp like a challenger for example
Because the Dodge Demon is a dragster. It doesn’t burn gasoline, it burns ethanol, it isn’t street legal, it doesn’t meet emissions or safety requirements.
Just about everything in engineering is about managing tradeoffs. Powerful engines cost more money. People who don’t prioritize performance will buy cars with other design priorities. This is especially true for a mass-produced consumer product with lots of competition.
Having a powerful engine isn’t the only part of a high performance car. There’s a famous reddit meme…
> It’s like putting a powerful engine in a stock Toyota Tercel. What will you accomplish? You’ll blow out the drive train, the clutch, the transmission, etc., because those factory parts aren’t designed to handle the power of an engine much more powerful than the factory installed engine.
A car needs to be able to direct that engine power through the drivetrain through the tire contact patches into the road in order to be useful. Very large amounts of power are beyond the skills of most drivers, though electronic assistance systems help.
https://youtu.be/u-MH4sf5xkY Here’s Engineering Explained on HP vs Torque. He has a lot of car-oriented content. https://www.youtube.com/@EngineeringExplained/playlists?view=50&sort=dd&shelf_id=2 has the playlists, including one called “Engines”.
Very generally, bigger engines produce more power and burn more fuel. Power is the torque (turning force) of the engine times the speed, so an engine can rev to very high speeds (high rpm) to produce power, but that requires much more precise building to get to 9000 rpm vs a more typical 5000-6000 rpm redline.
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