Interesting...I will try 89 next time I gas her up.

thats the beauty of EFI
You should run the 87 octane the electronics will compensate.

That is the myth run higher octane you get more power. The only power you can get from fuel is if your engine requires a higher octane to run otherwise you are seeing what you should be seeing un burnt fuel.

If your motor is blown then you usually require a higher octane depending on how much boost your running. Keep it under 7lbs and you can get away with 92 Octane.

I learned this lesson the hard way I used to have a high perf mo mo and ran Av-gas, then I switched to a naturally aspirated mo mo and ran Av-gas and all i did was clean my transom. It was bad, oh well we all have to learn.

Yep you only need enough octane to keep the flame front under control and not have detonation in you boat or car ,anymore than that and it ( the octane )) keeps the flame down ( kills the combustion heat ) and robs tons of power and turns your transom black due to unburned fuel !! this is a fact ,really!!! just use as much as you need ,no more it runs worse with to much octane


Also like I said earlier in the post watch old fuel ,it really does weird stuff and heat makes it worse ,,,with winter grade fuel the heat really does it in