My best guess is turbocharged to bring pressure at the carburetor to atmospheric pressure at sea level (1 atm.). So, you're not putting much more stress on the

My best guess is turbocharged to bring pressure at the carburetor to atmospheric pressure at sea level (1 atm.). So, you're not putting much more stress on the engine than it would get without the turbo at sea level, but you get constant engine performance up to a good altitude.