The 1.4L Turbo doesn't
require premium fuel. It just does best on it.
Dart user manual:
The DOHC 1st Gen Neons were the same. Could run on 87Octane but 91Octane was recommended for full power.
Turbo is simpler, part of the PCM programming looks for clues that 87octane is being used, like ping and detonation, then it just dials back the boost for 87octane.
The DOHC 1st Gen Neon PCM does the same, just switches to another ignition map if the ping/detonation indicates 87Octane is being used. No, its NOT the same as all ping sensor and retarding ignition. Every car will retard ignition if it senses pinging, for a few minutes. The DOHC 1st Gen Neon actually switch to another tune the rest of the drive, and it was more sensitive to pinging in the more aggressive mode for 91 octane, than most cars.
And plenty of DOHC owners found they got a little better mileage with 87octane than with 91 octane.