THE 1949 octane-number requirement survey conducted by CRC indicated that:
1.
Maximum octane-number requirements based on Research numbers of commercial fuels were 1-2 units higher than those based on primary reference fuels.
2.
Blends of diisobutylene, isooctane, and n heptane, matching the commercial fuels in Motor and Research octane numbers, followed the commercial fuels closely in antiknock behavior.
3.
About 50% of the customers’ cars knocked on the fuel found in the gasoline tanks.
4.
The spread in octane-number requirements of engines, which manufacturers consider representative of their production, was almost as great as that found among cars in service.
