modeler , 5 hours ago

Ackshually they do this, not with cars but, with WW2 era prop planes.

The Spitfire for example:

The Merlin consumed an enormous volume of air at full power (equivalent to the volume of a single-decker bus per minute), and with the exhaust gases exiting at 1,300 mph (2,100 km/h) it was realised that useful thrust could be gained simply by angling the gases backwards instead of venting sideways.

During tests, 70 pounds-force (310 N; 32 kgf) thrust at 300 mph (480 km/h), or roughly 70 hp (52 kW) was obtained, which increased the level maximum speed of the Spitfire by 10 mph (16 km/h) to 360 mph (580 km/h). The first versions of the ejector exhausts featured round outlets, while subsequent versions of the system used “fishtail” style outlets, which marginally increased thrust and reduced exhaust glare for night flying.

From Wikipedia