Was the OK1 mixed 30/32? On the CRG, VEN11 or VEN13? I’m not a super expert on those 2 chassis, but I think you need to be more specific than just being slower overall, so experts here can give you some tips…meaning are you seeing any symptom like hopping, sliding, over/under steer. What tire pressure are you using, weight/height of the driver etc…front geometry? Same track? When you say slower, are you comparing OK1 with a honda VS CRG with 175 Iame?
It would be great to understand where you are actually losing time too (hard braking? fast corners? slow corners?etc). Otherwise it’s very difficult to pinpoint what’s going on.