I recently did a bit of Wikipedia research on the original air-cooled VW boxer engine and noticed something: the compression ratios are way too low. The VW 1000, for instance, has a compression ratio of 5.8:1, which is preposterous and explains the toy-like power output. Why did VW make the compression ratios so low?
Because the engine was designed to run on fuel available anywhere in Germany or anywhere else the car could operate, which during the 30s when developed, could be quite poor quality fuel which was prone to detonation in high compression engines. Again for an engine in this period, this isn't an unusual compression ratio at all, the flathead when first introduced was only 5.5:1 and later upgraded to a whopping 6.3. they didn't have flatheads with a compression ratio above 7 until the 50s, at which point, the VW boxer also reached 7. Very late production VW units ran 8:1, not uncommon at that time in the US. Today with cars coming out at 10/11/12 to 1 compression it's low, but for the period it was entirely normal.
