My 1994 C180 which has a lot smaller engine than yours has 16 valves and 4 cyls and it goes 2800rpms at 100kph at the moment. This is after I ran a whole bottle of fuel injector cleaner through 3 tanks as it was doing 3000rpms at 100kph before this treatment. The A$10 treatment was very good and successful! I have replaced the entire exhaust system which had internal damage and it now runs like a dream! Costs me a flight to the moon, though,LOL!!!