Quote:
Originally Posted by Blacktree
A little off topic, but this is something I want to do with my project car. The idea is to make a rear diffuser, and route the engine exhaust into the front opening. For that car, fuel economy isn't really a concern. But less lift and/or drag would make it faster on the racetrack.  |
It's not *entirely* off topic. The basic gist of improving fuel economy is more advantageously rearranging the forces acting on the car, in particular the aero forces.
If you are going for a racing car, a common tactic is to angle the radiator to lean forward and then use a shaped hood bonnet. That gives cleaner flow at the nose, improved radiator performance, and downforce on the front wheels. It's also convenient, since everything is right there are the front, which means you can do professional ducting on the airflow. I almost did that to Champrius before I discovered I got better fuel economy increasing the hood insulation.
If you want to combine the radiator with the rear diffuser, I'd put the outlet into the wake ejected
above the diffuser plane. A thin linear rectangle 15% of the area of your inlet on top of the diffuser would be perfect. That ejects the air directly into the wake, harnesses the maximum low pressure for suction, and provides tiny but real amounts of thrust and downforce on the real wheels.
The biggest issue I would see is your airflow ducting. Optimally you'd want a squished horizontal oval shape of consistent cross sectional area to go directly from the radiator to rear end of the vehicle. But that would most likely inconveniently intersect the middle of the cabin, like in freebeard's pic.