Is It Safe to Do a Burnout? (Explained)
Doing a burnout as seen on TV, YouTube etc may look cool and be tempting to do, but is it safe and can it cause any damage to your car?
If a burnout is done for too long, your cars engine may overheat. It is possible for the gearbox and clutch to overheat too. If you have an automatic and you keep your foot on the brake for too long, the brake will wear out. You'll also wear the tyres down very quickly.
You can cause damage and wear out to the following parts of a vehicle if you do a burnout, no matter how long you do it for there is a risk of damage.
Clutch
Gearbox
Differential
Driveshafts
Engine
Tyres
Brakes

Are Burnouts Useful?
Burnouts do have a purpose in motorsports. If you have a set of slick or semi-slick tyres, it will heat up the tyre compound, improving the tyres grip to the track's surface. On drag strips, there's a "waterbox" to assist the burnout without causing too much stress on the powertrain.
The slicks have a particular natural rubber composition that gets sticky when heated, and they catch up every small bit of gravel or debris.
Burnouts have a use in motorsports such as drag racing, but in regular vehicles, heating up the tyres by doing a burnout does not have as much of an effect on improving grip.