Originally posted by Palmaris Europe
I believe Associated or Serpent 60wgt oil is the equivilent although not totally sure.
I had a chart once with the mugen/asso oil conversion but I can't find it at the moment. It was definitely not 60W I think it was more like 55W or a bit less. It would be best to just try a bit harder and get the mugen oil for a mugen car so you can compare setups etc.