Propane combustion is much cleaner than that of coal or unleaded gasoline. The required fuel is premium 91 octane unleaded. Compression ratio is 10.0&colon;1 and uses regular unleaded gasoline. Engines run on unleaded fuel closely resembling publicly available petrol. It also has 2 CCRs producing Unleaded Petrol of High Octane. These engines also featured induction-hardened exhaust seats for use with low-lead and unleaded gasoline. Beginning in 1972, all engines were designed to run on unleaded gasoline. Algeria replaced leaded with unleaded automotive fuel only in 2015. Running on unleaded petrol, this engine had an output of . Previously, Holden had considered discontinuing their V8 engine rather than adapting it to unleaded petrol. All four models were designed to run on super unleaded petrol only. Referring to EU EN 228&colon;2012 and Directive 2009/30/EC, Automotive Fuels of Unleaded Petrol. The ET model also saw its 1.5-liter turbocharged engine updated for unleaded fuel. All U.S. market Gremlins featured catalytic converters that required the use of unleaded regular-grade fuel. All U.S. market Matadors featured catalytic converters that required the use of unleaded regular-grade fuel.