Dwight Howard -- I'm No Longer Superman ... Call Me 'The Flash!'

Dwight Howard is putting his Superman alter ego on ice for a while and re-emerging as ANOTHER comic book bad ass, THE FLASH ... and he's starting the re-branding process with a new car.

TMZ Sports has learned ... the Houston Rockets star has commissioned some heavy duty Flash-themed work on his 2015 Dodge Challenger SRT Hellcat with the guys at 713 Motoring in Houston.

We spoke with the owner, Ash, who tells us D12 has always been known to "superhero" his cars and usually went with a Superman theme.

"But when he came to the Rockets, he wanted a change ... he said he no longer wanted to be called Superman, he is now Flash out here in Houston."

Ash says the project will run around $65k -- and included everything from a custom paint job ... to a pimped out steering wheel ... and custom Flash logos on the wheels, hood, seats and gas cap.