Very recently Peter and I tried a fuel mix of HP2 ( our oil of choice for years ) and Shell V power 91. When first pouring the two together, almost all the HP2 stayed on the bottom of the mixing jug. After giving the jug a vigorous shake, all seemed well mixed. Both the fuel and the oil are dark blue. We half filled Peter's Pioneer/mono bag for a static fire, and very soon the eng. was running very rough with almost no response. All our motors on our usual HP2/110 race fuel run perfectly. Because the only change was the fuel, we evacuated the Shell from the bag, and at the end ( when the bag was going clear ), we could see were the oil had separated. A subsequent clear bottle pour of the mixture, showed very quickly that the Shell 91 was floating on top.

Shell 91 V power is quite popular up here as a clean ( with no ethanol ) performance fuel for high performance cars. I don't know if the separation had to do with the nitrogen additive or not, but it clearly doesn't mix with Honda HP2 for 2 stroke applications. It may be fine with other oils, but we are so happy with our race fuel, I don't think we will try anything new for a while.

This was just our experience with these two products, but we thought we should pass along our results to you guys.

Just wanted to clearify; The Shell 91 that I got was from a very busy ( main intersection ) station, and I cleared the pump and hose by pumping several litres of it in my car first. So it was pure 91 and very fresh.

Hey Dennis you some how didn't have standard oil in the jug before or add to a jug. Sounds to me you have mixed synthetic and standard oil to gether. They do not get along together

No, that's not the case. There has been nothing but HP 2 in the mixing jug or in the supply "jerry can" used to fill the bags.