This picture was taken by Carl Werner in Sicily (possibly in 1941) and showing a Junkers Ju 88A from 2.(Fern)Staffel / Aufklärungsgruppe 123 being refueled by Luftwaffe groundcrew from a Flugbetriebsstoffkesselkraftwagen Kfz.385 (auf Opel Blitz 3t S) refueling truck. The Octane rating of the Luftwaffe's standard aviation fuel was 87 Octane (B4), this was the same Octane as used for all Wehrmacht Vehicles including Panzers. C3 on the other hand was 96 Octane and this was completly reserved for the Messerschmitt Bf 109's running the DB601N, DB605AS, and DB605D-2 (C3 fuel Only) engines. As for the vehicle fuel, although the Fuel was 87 Octane throughout the war, it was the quality of it that suffered in the later part of the war when Allied bombings intensified, because a large part of the fuel was refined from Lignite Coal Feed Stock in the Fischer-Tropsch & Bergius processes. Because of these processes, the Fuel was more benzene than "Petroleum" (from Crude Oil), so ideally it should use a petrol with a small percentage of benzene (because of it's "Anti-Knocking" ability and it's Octane Boosting properties). What the German got is a benzene fuel with a small percentage of Petrol, so it just leads to problems because in low compression motors it predetonates (causing rough idle at all rpm) and simply burns out motors (all German vehicle motors were low compression types).