Can E 10 90 octane be used is the RDX without major problems.
In Jamaica WI only 90 octane is available , I am aware that 91 and upwards should be used. So far the 90 works but I suspect I have lost a bit of power.

 

Welcome to the forum sah!

Any e10 can be used in the RDX. Just keep on using the 90 and dont even think about the currently available 87-e10!!!