how can a car go fast

[VanMadelyn]

A car's ability to go fast is determined by a combination of its power-to-weight ratio, aerodynamics, and traction. Simply having a powerful engine isn't enough; the car must be light enough for that power to be effective, shaped to slice through the air with minimal resistance, and have tires that can transfer the power to the road without spinning. For most drivers, improving a car's speed safely means focusing on legal and practical modifications rather than just pushing the engine to its limits on public roads.

The most fundamental concept is the power-to-weight ratio. This is exactly what it sounds like: the vehicle's horsepower divided by its curb weight. A lighter car with a moderately powerful engine can often accelerate faster than a heavy car with a very powerful engine. This is why sports cars like the Porsche 911 use lightweight materials such as aluminum and carbon fiber. Reducing a car's weight is one of the most effective ways to increase performance.

Aerodynamics plays a critical role, especially at higher speeds. As a car moves, it must push air out of the way, which creates drag. A car with a sleek, low-profile design and features like a rear spoiler (which creates downforce to press the tires onto the road for better grip) will encounter less resistance. This allows the engine's power to be used more efficiently for forward motion rather than fighting the air.

Finally, all that power is useless without traction. High-performance tires are the single most important upgrade for improving acceleration and cornering. They provide the grip needed to put the power down. This is complemented by the car's drivetrain. All-wheel-drive (AWD) systems typically provide better launch traction from a standstill than rear-wheel-drive (RWD) or front-wheel-drive (FWD) cars, as the power is distributed to more wheels.

Here’s a comparison of how different performance metrics contribute to a car's speed, using examples from the sports car segment:

Car Model	Horsepower (hp)	0-60 mph Time (seconds)	Top Speed (mph)	Key Performance Feature
Mazda MX-5 Miata	181	6.7	137	Lightweight chassis, rear-wheel drive
Ford Mustang GT	486	4.2	155	High-horsepower V8 engine
Tesla Model S Plaid	1,020	2.3	200	Instant electric torque, all-wheel drive
Porsche 911 Turbo S	640	2.6	205	Turbocharging, advanced all-wheel drive
McLaren 765LT	755	2.7	205	Extreme lightweight construction, aerodynamics

Ultimately, for safe and legal speed, the best investment is often advanced driver training. Understanding vehicle dynamics and proper driving techniques on a track can make any car feel faster and more capable.

[Alex]

It's all about the launch for me. You need sticky tires and a good surface. Ease into the throttle, don't just stomp on it, or you'll just spin the wheels. Once you're moving, keep the revs high in the power band—that's where the engine makes its best power. Shifting smoothly is key. But honestly, the driver matters more than the car. Knowing how to control a slide and hit the apex of a corner is what makes you fast.

[RebeccaFitz]

From an engineering standpoint, speed is an efficiency problem. We maximize the thermal efficiency of the engine to extract more power from fuel. We then minimize losses by reducing weight with advanced composites and optimizing the aerodynamic profile in a wind tunnel to lower the coefficient of drag (Cd). The power must then be effectively transmitted through a well-tuned transmission and a limited-slip differential to the tires, which are specifically formulated for optimal grip at operating temperature.

[StFaith]

I don't need a race car, just a car that doesn't feel sluggish merging onto the highway. For that, you want strong low-end torque, which you get from a turbocharged engine. A responsive transmission that downshifts quickly when you need to pass someone is huge. Keeping your car well-maintained—clean air filter, good spark plugs—makes a difference too. It's not about top speed; it's about having power available right when you need it for daily driving.