[aerohead]

I'll pull some things together for your attention. My inefficient ' filing system' may make for a 'slow' process.
As to the Ford Sierra/ Merkur XR4Ti, you'll need U.S.PATENT 4,533,168, Janssen et al., August 6, 1985.
And with respect to that patent, if you can track down: German Offenlegungsschrift No. 27 37 638, this will provide context to the genesis of what Janssen et al. accomplished with Sierra / Merkur ( you'll find reference to the German reference within the PATENT ).
Also, you may find some aeronautical materials in the public domain to be germane to road vehicle aerodynamics ( JANE'S All The World's Aircraft ).
Biomimicry ditto.
Human-powered submarines.
International Human Powered Vehicle Association.
World Solar Challenge.
Shell EcoMarathon.
SAE Supermileage Competition.
Experimental Aircraft Association ( EAA ).
Hypercar Inc., Rocky Mountain Institute, Snowmass, Colorado, USA.
Speed Week and USFRA's World of Speed, Bonneville International Speedway, Wendover, Utah, USA.
American Society of Heating Refrigeration and Air Conditioning Engineers ( ASHRAE ) Handbook.
ISO / National Plumbing Code, USA.
Very recent, first, ever, 'AERO-LOADER', backwards' rooftop cargo carrier, by Calix, tested in Norway ( You-Tube video ).