You might mean a graduated ND filter? They have half the filter dark, so you can put that part on the sky while the clear part is over the ground. It is kind of an old-school fix from the film days, before post processing on the computer existed, but people do still use them and they can work if you could line it up well with your image/composition.
A regular ND would just darken everything, which would allow you to use a slower shutter or a wider aperture, but neither of these would help with your sky being brighter than your subject.
If you underexposed for the car by a stop you might be able to use graduated filter in post processing to then raise the car a stop while darkening the sky one more stop and that plus your polarizer might give you some sky color and detail back.
Scott
Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites
Why do so many people say "FER-tographer"? Do they take "fertographs"?
