Key Facts & Details

Image reprinted from Shell Oil Co Engineers book “Fuel Economy of the Gasoline Engine,” page 223, ISBN 0-470-99132-1

Early MPG Milestones

The previous record of 49.73 m.p.g. was broken in 1939 by a 1947 Studebaker achieving mileage of 147 m.p.g.; in 1969, a Fiat 600 established a record of 244.35.  In 1973, the 1959 Opel P-1 Hardtop discussed above shattered that record with its 376.59 m.p.g. result.  Although heavily-modified experimental cars can today achieve m.p.g. of 2,000+ in specific test conditions, these high-performing road cars—Studebakers, Fiats, the Opel—perhaps demonstrate that fuel efficiency and performance are not so much a function of scientific possibility as will.

Documented Track Results

The 1959 Opel established its stunning record as it appears in the above photo—on a closed airfield circuit course at a stringently enforced minimum of 30 miles per hour (driving style was not restricted, but tuning modifications were limited to carburetor and ignition adjustments only).

Description and Modifications

The 1959 Opel is a CaraVan station wagon whose roof was chopped (lowered) and made into a pickup, with a 2-speed chain drive, 4-cylinder motor that is nearly completely insulated (including the entire radiator), a strange air induction (the carburetor has  a ¾” bore), and a mid-engine replacement.  Its rear wheels are connected to the center of the axle.  The individual names of the Experimental Team members who developed and prepared the car are still proudly emblazoned on its rear deck.

Patented Gasoline Economization

A 1988 patent application by Paul M. Brown[1] both cites and explains one theory behind the Opel’s record-setting performance: “The chemically correct air/fuel mixture for total burning of gasoline has been determined to be 15 parts air to one part gasoline or 15/1 by weight. Changing this to a volume ratio yields 8000 parts air to one part gasoline or 8,000/1 by volume. The system of the present invention vaporizes liquid fuel before the fuel enters the engine. Theoretically, a homogenous mixture can yield gas mileage in excess of 300 miles per gallon.

[1] Source: Free Patents Online: Application No. 07/216960 (Filed: 07/11/1988 by Paul M. Brown; Boise, Idaho)