Symmetrical foils versus asymmetrical foils

Generally, all symmetrical foils for a given camber (thickness) have similar Cl. If we consider (high lift?) asymmetrical ones of same thickness and for similar Reynolds no. Then can the same be assumed, and approximately how much larger is the Cl of the asymmetrical ones: x1.5? x2?

 

You have a number of things mixed up. Camber is what you have left when you take away all the thickness. Camber is what makes an asymmetrical foil out of a symmetrical one.

There's no hard rule for what the maximum lift is for an asymmetrical section compared to a symmetrical one. It would depend on the shape of the basic symmetrical section, the amount and shape of the added camber, and the Reynolds number.