What happens to the car if brake and accelerator are pressed at the same time

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If you’ve ever played racing games, you might remember doing something that included pressing the forward and back buttons together and watching the car do various actions like doing a burnout or just sitting there and revving.

Did that ever make you wonder what would actually happen if you tried that to your car in real life but were too scared to try as it might wreck your car? Well, we might have an answer for you as many people over the internet have been coming up with this same question lately.

To start off, it’s important to mention that there are multiple outcomes to this scenario depending on how old your car is, if it manual or an automatic or if it front, rear or all-wheel-drive.

As far as the age of the car is concerned, newer cars that have advanced safety features simply won’t allow you to press the brake and the accelerator together. So, even if you attempt to do it, nothing would happen and that would be anticlimactic.

In most performance cars, the practice of pressing the brake and accelerator together is quite common and is known as launch control. Launch control allows you to get the maximum possible acceleration out of your car from a standing stop.

What it does is let you press the accelerator all the way with your right foot while keeping the engine at a set RPM while the brake is also pressed with your left foot. And when it’s time to go, all you have to do is take your left foot all the way while keeping the accelerator floored and the car “launches” forward.

Image: porscheownersmanuals.com

The theory behind this is that a car engine does not make its peak power in lower RPMs and thus the acceleration will be slower compared to when the engine is in the “power band” (usually around higher RPMs). Launch Control is usually more common on automatic transmission cars compared to manual cars as a manual performance car is becoming a rare breed.

There are two main types of automatic transmissions; conventional and clutch-based. In a conventional automatic, a torque converter is used which allows a certain amount of slippage between the engine and wheels. That is why in most automatic cars, the engine does not stall when the car is left on Drive and is not moving.

When you press the brake and accelerator together, the torque converter allows slippage to a certain extent and doesn’t let the engine rev higher than a certain RPM and when the brake is released, the car bolts off.

Image: carfromjapan.com

A clutch-based automatic uses a clutch (or two in the case of Dual-Clutch transmissions) that’s automatically actuated by the car when it needs to move. Unlike a torque converter, a clutch does not allow any slippage, so it cannot be left engaged while the car is not moving otherwise it could stall the engine or burn the clutch plate.

During launch control, the clutch is automatically deployed when the brake is pressed so the engine is free to rev as the accelerator is also floored. When you take your foot off the brake, the clutch is simultaneously released so the car can accelerate.

Another use of pressing the brake and accelerator together is called a “Line Lock”. It is usually used in rear-wheel drive cars to warm up the tires for better traction.

A line lock is a burnout where the front wheels are locked by the brakes and the rear wheels spin all the while getting the tires warm through friction with the ground below.

Line lock is mostly used before a drag race to get the best possible grip off the line or can be done recreationally for the sake of some old-fashioned burnouts.


However, it is to note that we have been talking about performance cars so far that have these features inbuilt.  It is not recommended to try launch control or line lock on your normal everyday car as you may damage something.

To find out if your car supports these, check the owner’s manual. If it’s mentioned there, follow the steps carefully as each car has its unique way for activating either of these functions.

If you attempt to launch a car that isn’t made for a launch control, you can end up damaging the car. This practice is heavy on the engine, transmission and even the brakes. Make one mistake and you can end up with an overheated engine, a failed transmission, a burnt clutch or even early brake failure.

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