Why Do Newer Cars Have Smaller Engines?

Close up of a small 4-cylinder engine inside an engine bay

If you think back to the muscle cars of the 60s and 70s, you probably remember their massive engines. Today, engines are a lot smaller, but they tend to be just as powerful. Is this just a trend, or will big engines come back?

The main reasons why small engines are favored are because they’re more fuel-efficient, offer the same power, are less expensive to make, and they’re lighter. As engines keep getting smaller, the standard car will be able to perform even better.

In this piece, I’ll explain why newer cars have smaller engines. You’ll quickly find out that this isn’t just a trend, and engines will probably just keep getting smaller.

The Role of the Engine

You probably already know this, but the engine is one of the most important parts of your car. Through a series of fuel mixture, compression, ignition, explosion, and transferal of power, your car will move. All of these steps happen within the engine.

How an engine works
How an internal combustion engine works.

Without an engine, your car won’t go anywhere. It will just be a glorified hunk of metal, rubber, and plastic.

When you pop your car’s hood, you’ll notice a big block of metal in the center — that’s the engine.

It’s True, Engines are Shrinking

I just wanted to clarify something: it’s a fact that modern engines are smaller than the ones in the muscle car generation. I won’t be debating this fact, I’ll just be describing why it’s happening.

Smaller Does Not Mean Fewer Horsepower

An odd characteristic about engines is that the size doesn’t equate to horsepower. A tiny engine today can have a much higher horsepower than an engine 50 years ago.

The horsepower is generated from the internals of the engine – it depends on how well the fuel is mixed, compressed, ignited, and how well the moving parts work with each other.

Under the hood, the size of the engine doesn’t tell you much.

Benefits of Smaller Engines

I think the best way to explain why newer cars have smaller engines is to talk about the benefits of smaller engines. After reading through some of these, you’ll have a better idea of why auto manufacturers are opting for these smaller options.

They Weigh Less

One thing is definitely true about smaller engines: they weigh a lot less. When it comes to your car’s performance, weight is a massive factor. I went more in-depth on this concept in my guide on horsepower, but the quick version is that horsepower needs to be considered alongside the total weight.

That means that dropping a smaller engine in the same car with the same horsepower will allow it to perform better.

Engine visible through a transparent vehicle illustration

In addition to overall weight, the weight distribution is also something that affects a car’s performance. This refers to how the weight is spread out across the car. Since most of the mechanical power is under the hood, it’s easy for the front side of a car to be weighed down.

This messes with your ability to corner, accelerate, and how aerodynamic the car is.

Technology Is Getting Better

You can also look at the progression of a typical computer if you want to understand more about engines. It wasn’t too long ago that computers took up entire rooms and could barely do simple math.

Today, a fully-functional computer can be the size of a credit card. As technology gets better, engineers and designers are allowed to make things much smaller.

The same is true for engines. As tolerances shrink, materials enhance, and our understanding of engines gets better, they can be much smaller and still perform the same.

Engines are More Powerful

Just to reiterate, modern engines are a lot more powerful than they’ve ever been. If you made an engine today that was the same size as the ones in the 70s, the new version would be way more powerful.

Putting too much power under the hood is never a good idea. It’s a quick way to break parts and make an unreliable car.

Large V8 engine close up inside the engine bay

With that being said, it makes sense that engines shrunk. It was never about how big the engine was, simply how much power it could produce.

If you look back at the history of the Chevy Silverado, you’ll get more insight into how much more powerful the engines have become. Their 2007-2013 generation offered a 4.3L V6 that could produce 195hp. Their 2019+ generation offers a 4.3L V6 that cranks out 285hp. That’s the same engine size that makes way more power.

Nowadays, many car manufacturers are opting to make 4-Cylinder & 6-Cylinder iterations along with a turbo or a supercharger instead of a big-block V8.

Engines are More Fuel-Efficient

When you get a smaller, lighter part that delivers the same amount of power, you’ll be left with a more fuel-efficient part. This is exactly what’s happening in smaller engines.

If you remember back to your parents’ first cars, they might have boasted an EPA-estimated 14 MPG. Today, most compact cars offer MPGs in the high ’20s and ’30s. That’s more than double what it used to be.

For a daily driver, the fuel-efficiency is a big consideration. Better efficiency means fewer trips to the gas station and less money spent annually on fuel.

Higher Compression Ratios

Another big improvement is seen in compression ratios. To put it simply, this term refers to how much the gas can be pressurized before igniting. A higher compression ratio roughly translates to more power, since power is a byproduct of this compression and ignition phase of a motor.

Close up of a Mazda 3 SKYACTIV engine 4-cylinder
Mazda 3 SKYACTIV engine with a 14:1 compression ratio

Back in the day, a compression ratio would typically be a single-digit number, like 5:1. Today, a standard car can easily achieve a compression ratio of 14:1.

Another result of better compression ratios is more favorable fuel efficiency.

On-Board Computers Make it Possible

If you didn’t know, your car works in junction with a computer that’s hidden somewhere in your car. This computer uses complex logic and code to run daily operations.

The computer even controls how the pistons of your engine fire. A great example of how well these computers work is the Mazda MX-5 Miata. It only has four cylinders and 2 liters to work with, but it produces a reliable and admirable performance.

The computer will control the timing of the valves, when sparks are created, and the exact pattern the engine fires off.

Less Expensive to Make

When you’re looking to manufacture something, smaller is typically better. Until you get into tiny items, this rule of thumb holds.

A smaller object is less expensive to make than a larger one. It takes less material, less machining time, and it’s easier to transport.

Car Manufacturing

When it comes to engines, smaller engines are less expensive to fabricate. Since it costs the manufacturer less, they can also sell the cars for less. As a consumer, a smaller engine means that you’ll pay less for the vehicle.

It also allows manufacturers to make them quicker and produce more cars annually.

More Space in the Engine Bay

If you’ve ever worked on your car, you know that space is a premium. It’s often difficult to reach bolts to remove them, especially in the engine bay.

With a smaller engine, it frees up a little more space. It’s still tough to get your tool in that tiny gap, but it’s less difficult than it used to be.

Some Downsides of Smaller Engines

As great as smaller engines are, they also have a few major downsides. Let me talk more about that in this section.

Harder to Get Up to Speed

A common issue with smaller engines is that they take longer to get up to speed unless it has forced induction of course. If the manufacturer goes too small with the engine, it could be underpowered for the vehicle size.

Close up of the instrument cluster speedometer in the dashboard orange amber backlighting

This means that the 0-60 and top speed values will be underwhelming.

The solution is for the designer to use a slightly bigger, more powerful engine. This comes with a bigger cost and potential for placement issues.

Less Satisfying Engine Noise

This might just be me nitpicking, but modern engines don’t sound as great as they used to. Revving an old Mustang used to put a smile on my face. Today’s Mustangs still sound great, but it’s a lot less satisfying to hear them roar.

They Don’t Last as Long

Anecdotally, smaller engines don’t last as long as bigger ones. Smaller parts require less force to break, meaning that regular wear and tear can be more disastrous.

Small compact car broken down on the side of the road with steam coming from the engine bay on a hot sunny day

Modern cars can easily last hundreds of thousands of miles, but they could potentially last longer if modern engines were bigger and more robust.

Conclusion

Cars have increasingly smaller engines as a way to reduce manufacturing costs, improve performance, and increase fuel efficiency. These smaller engines can create just as much power as the old muscle cars with massive engines.

If you have more car questions, check out the rest of my blog. I put together answers to some of the biggest questions surrounding the automotive world. I also have a list of car products that can make your life a little easier.

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Ernest Martynyuk

An automotive enthusiast who's been tinkering with vehicles since I was 15-years old. Repairing automotive electronics has been my main job for over a decade now and have a passion for everything technical regarding cars.

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