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Knowing your car: Transmission and Engine Dynamics

Automatic vs. Manual

Many of us are familiar with the age-long debate between automatics and manuals. For a long time, automatics offered simplicity, whereas manuals offered better fuel economy and greater performance.

Today, automatic transmissions are quicker and more fuel efficient than manuals. Most modern race cars use automatic transmissions where you can choose gears using paddle shifters or buttons. In fact, you can barely find a supercar that has a traditional manual transmission anymore.

There isn’t a wrong transmission to track with. Don't mind the purists who preach manual or nothing. However, you do want a transmission where you can manually select your gears - doesn't matter if it's a manual or an automatic with paddle shifters. This is for better control, because on track you will often need to shift into a lower gear before a turn so that when you get out of the turn, you’re ready to accelerate. Most street-tuned automatics won’t be able to respond fast enough and may shift at the wrong time which may disrupt your driving and the car.

Even if you have an automatic that can respond lightning-fast, like the Porsche PDK, you’ll learn more about racecraft if you opt to select your own gears.

Horsepower vs. Torque

People obsess over horsepower as an indicator of how fast their car is. Car manufacturers love horsepower and always try to one-up their competitors' numbers. Indeed, horsepower measures how much work your engine can produce in a given amount of time, so high horsepower means your car can go faster for longer.

But horsepower is not the be-all end-all. Torque is also important. This less well-known figure measures how much twisting force your engine can apply. Torque is responsible for the feeling of being pushed back in your seat when you mash on the gas.

A car with high torque can accelerate quickly off the line and pull a lot of weight. Conversely, a car with high horsepower can hit a high top speed.

However, horsepower and torque are closely-correlated mathematical concepts. You’re never going to have a car with 1000 horsepower and 100 lb-ft of torque, so it’s not useful to debate which one is better. Just know that horsepower and torque figures together paint a picture of an engine’s potency.

This is a fairly simple explanation. If you want to learn more about the mechanics of horsepower and torque, refer to this excellent Engineering Explained video.