Unleaded high octane fuel (Opel Ascona C)

1. All overhead camshaft engines used in the Opel Ascona models under consideration have valve seats made of a material that allows the use of high-octane unleaded fuel, provided that the following is met.

2. Using unleaded fuel may cause detonation at high engine speeds, which is not audible but may cause engine damage. To prevent this from happening, the ignition timing angle should be reduced by 5 degrees. (see chapter 4).