According to this article
Mileage Miracles - Shell Fiat
*Ben Visser, a Shell research group employee, drove it. Doesn't say who built it. One pic shows "Martin, Visser, and *******" on the fender.
*It ran a 14 mile course along River Road, Wood River, Ill. Don't know if it was all downhill? Paved? Google maps doesn't show any River Road today.
*Top was chopped, but so what? Contemporary pics show no glass in it.
*Article says bicycle chain drive; pics clearly show heavier chain, so article isn't gospel.
*Article says aircraft tires @ 200 psi; another source said 150.
*Pulse from near stop to 13-14mph; average 9 mph.
*There's a pic of Ed Brown winning the motorcycle division. With a loaded sidecar. On a dirt road.
*This page
Shell Mileage Marathons - Shell Fiat does not jive with the article. One begins to wonder if an accurate account exists at all.
*From 1981 Texas newspaper(?)
http://www.59fiattestcar.com/vehiclesofinterest.htm:
*Visser is a Sr. Research Engineer in the fuels performance section.
*Cars built by Shell development employees on their own time.
*This time P&G is from 3 to 12 mph- done by ear since speedo cost 10 mpg.
*In '81 optimal fe for stock cars was at 30-40 mph. 55 vs 70 mph was 20-25% better fe.
*14 ply a/c tires, tread ground off, 200 psi front, 300 rear.
*Visser says car owners should run sidewall max, at that time 32-35 psi.
*Ran straight coolant at 280 deg., intake 240 deg.
*Stoich 14.2-14.5:1 depends on fuel; fe increases up to 10% leaner than stoich then drops off... but it's "more art than science".
*CR was 9 or 10:1 :/
*Says it has a scooter carb, but it looks like a mower carb to me.
*Higher CR > low; long stroke > short; tall gears > short... until engine strains too much.
*The Opel weighs 2400 lbs... I don't think so.
*Now it has a windshield Hmmm.
*Deposits in the intake
improve fe.