Which certain brand of fuels you used had the knocking effect? I dont seem to notice any knocking-effect on the cars. The only observation I have is the carbon build-up when I took the spark-plugs out for a check. It was BLACK! I am hopinh V-power would knda clean it up , or otherwise to go for carbon-cleaning. Strange to see so much carbon build-up esp. since its hardly a year since the overhaul ...
126 tailed by a 203, 129 leading the pack.