Air cooled fuel efficiency.

[Dawie]

Air cooled engines have been developed by some to be fuel efficient, Porsche 911 is one example,993 has high squish combustion chamber with twin spark plugs that allow 11.6 :1 compression ratio.
After the fuel crisis of 1973 fuel consumtion became important,manufacturers started adapting their engines for reduced fuel consumption.By that time VW were already developing their watercooled Golf and Passat cars,it was not in their interest to improve their air cooled engines for fuel consumption,that would make the changeover to watercooled more difficult for them.

Here is an article of Jon Karcey who developed the type 1 engine for reduced fuel consumption.However,the Americans were not interested ,fuel was still real cheap there.This article was in VW Classics,about 1982.
(Battling with Photobucket,i click on image code there , it shows "copied",nothing happens here,i will keep trying)
Note that US gallons are smaller than UK gallons.54 miles per US gallon is 4.4 Litres per 100km.There are a few errors in the article, the comma is in the wrong position at the gear ratios on the last page.
Hot VWs and Popular Mechanics also placed articles about his research.

[Tony Z]

when it shows copied, just come back to this forum and press ctrl-V or right click and select Paste. The link will be here as you need it.

[Dawie]

See the pictures are a bit blurred,here are some details:
The engine made more power than a 1600,got 54 miles per US gallon (around 4.4 L per 100km) in a Karmann ghia body.It was tested by various magazine editors.There was a place that built engines to this specification.It was tested well over 100 000 km.

Dual pressure relief case with late standard doghouse fan and oil cooler.
1415cc
77mm pistons from 1300cc,
76mm counterweigted crank,
1300 single port heads,exhaust port ported,
9 to 1 compression ratio,
special camshaft with less duration,higher lift and lobe centres changed,
Bosch SVDA with modified advance curves,
Electronic ignition,
Dual carbs,first used Solex Kadrons with custom made 25mm venturies,
later changed to twin Weber ICT with 24mm venturies.
Taller final drive and 4th gears.
Bigger heavier crankshaft pulley.

There is a series on economy tuning currently in Hot VWs, Jake Raby has also experimented,using type 4 engines.