In Reply to: Re: Oil, Conventional or Synthetic posted by Charles Krammin on December 13, 2017 at 08:57:37:
Straight from Honda:
Honda engines are developed, tested and certified with petroleum based motor oils as a lubricant. Synthetic oils may be used; however, any motor oil used in our engines must meet all oil requirements as stated in the owner’s manual. In addition, recommended oil change intervals must be followed.
Keep in mind many of today's synthetic oils are predominately highly refined (Group III) petroleum oils rather than more traditional built from scratch "test tube" synthetics like PAO's (Group IV) and esters (Group V). The blending process for commercial "synthetic" oils combines all of three categories of base oils in widely varying proportions and as a consequence broad generalities like synthetic versus petroleum are very blurry. In fact you will have to work long and hard to determine what proportions of those three categories are in an OTS bottle of "synthetic" oil because the vast majority of blenders do not share that information. What they do share is performance metrics which is what engine OEM's care about.