Engine

Engine (エンジン) is a Quirk used by Tenya Iida and Tensei Iida.

Description
Engine grants both Tenya and Tensei engine-like protrusions that allow them to move at extraordinary speeds.

Through their amazing speed, both Tenya and Tensei can easily travel through long distances, flee from threats and chase after foes, as very few people can react or catch up to them.

Tenya's Usage
Tenya's Quirk manifests around his calves.

Those engines give Tenya massive leg strength, allowing for increased kicking power. Consequently, Tenya's fighting style ends up revolving around fast and powerful kicks, which are strong enough to crush even metal.

Furthermore, he can adapt to the situation at hand by switching between gears. There are at least three confirmed gear settings, but he needs to go through each one in proper order as he accelerates further. Tenya once observed that he could only switch up to third gear for a 50-meter dash, implying he needs more distance to achieve his maximum speed.

Jamming the mufflers of the leg engines will cause them to stall. The same thing will happen once he activates his Recipro Burst move, as a trade-off for a short-timed, but immense burst of speed.

Tenya's engines are fueled by orange juice, while carbonated drinks make them malfunction.

Named Super Moves

 * Recipro Burst (レシプロバースト): This move allows Tenya to forcibly accelerate his Quirk, greatly enhancing his speed for 10 seconds but at the cost of disabling his engines for a short period of time. Even Shoto Todoroki could not fully evade Recipro Burst and admits that he expected no less of its incredible speed.
 * Recipro Extend (レシプロエクステンド): After Tenya manages to cool down the negative effects of Recipro Burst, he regains even more acceleration than before.

Tensei's Usage
Tensei's Quirk gives him two exhaust-like engines at the end of his elbows.

Because his engines are located in his upper body, Tensei is capable of boosting himself vertically, allowing him to acrobatically climb up walls. The engines can also be used to slightly hover, slowing down his descent. Despite this, Tensei is perfectly capable of propelling himself forward, covering long horizontal distances as well just like his younger brother. It's unknown if he has to change between gears like Tenya.

However, Tensei has noted that he can't make tight turns properly when at high speeds, meaning that he has to slow down in order to do so. Also, because he doesn't use his legs for running, he can't use them as brakes, so if he crashes into walls while at top speed, it can result in him seriously injuring himself. As such, he has airbags installed into his costume for his safety.

Named Super Moves

 * Recipro Burst (レシプロバースト): By over torquing his engines, Tensei is able to produce an explosive burst of speed. This also causes his engines to overheat.
 * Rocket Charge (ロケットチャージ): Tensei's hero costume increases and focuses his engines' output, affording him greater acceleration and launching him into the air, like a rocket. This causes his engines to stall.

Trivia

 * This Quirk is similar to Jet, as both grant the user propulsion devices in their lower bodies that provide enhanced speed. The main difference is that in Jet they are located at the bottoms of feet and provide enhanced jumping, while in Engine they are located in the lower leg and provide enhanced running.