I had some indirect experience with their oils and I did look into it and talked to one of their sales persons. As a matter of fact, my local Penzzoil oil change place sells them.
It is a very good oil but their marketing or evasive definitions tuned me off.
A fellow instructor at my university (he teaches heavy equipment) ran a batch of their Multi-Vis Motor Oil (15W-40) in his Chevy diesel pickup truck for 26,000 miles with oil analysis every 5kmi. The oil was still good to use at the 25,000 mi analysis but he could not take it anymore and changed the oil. He is a Royal Purple believer and his truck has over 170,000 miles as of today. He uses it year round here in Michigan.
However, had he used Chevron Delo 400, Shell Rotella T, or Mobil Delvac, he might has been be able to go 26,000 miles as well. That is obviously an open question.
Anyway, back to Royal Purple. They have several oil lines but the main two are
Multi-Vis Motor Oils and Racing Oils.
Their racing line uses a 100% synthetic base stock. I have no doubt about that.
However, they call the Multi-Vis Motor Oils "Synthetic Motor Oils" but then said they are not 100% synthetic in their FAQ at
I quote that item:
"If your street products are not 100% synthetic, why are they priced similar to a full synthetic?
The Synerlec technology provides the best protection and performance increases available, however, it is very expensive. We have blended our street oils to exceed the performance characteristics of any other blended or "Full" synthetic. If having a full synthetic is important, we have our racing line which can be considered a "Full" synthetic."
So as you can see, their Multi-Vis Motor Oils is not 100% synthetic.
I talked to one of their sales persons based in the Detroit area. Being a sales person, he was very vague at this. I point blank asked him: "which one is more synthetic, Mobil 1 Tri-Synthetic or Royal Purple Multi-Vis". He point blank answered " Royal Purple is more synthetic than Mobil 1".
That finished my interest in Royal Purple. Although Mobil 1 Tri-Synthetic is not a 100% synthetic oil (in my book), I doubt that Royal Purple is "more synthetic" (but maybe he is right). From what I heard, Royal Purple uses a synthetic-blend base stock but a proprietary synthetic additive package called "Synerlec."
All major oils are good nowadays but price points are also important too.