Yeah, I brought up an old thread.
We finally got a station here that has E15 and E85. I converted out 2016 Suburban and it runs so much better on E85 with the Black Bear Tune. Now on my 2019 Silverado with the 6.2. As for now, the cost to convert it is to expensive for the benefits. But I do mix E85 with 93. I can't go any higher than 10 gallons of E85 or I get a CEL for running lean on both banks. The Silverado runs way better. As stated in all the posts on here. To me the benefits are the main reason for using it. Now that it's 2024, the cost spread isn't what it used to be.
The local rice burners that are tuned and boosted love it. We had one source to get E85 before a chain, Sheetz opened up. It was a pain to get to the pump. It was back on the side of the building and hard to get my large vehicles backed in to the pump. But the locals with the tuned imports said it tested on average E65 for the most part.
I can say that our Suburban would get 22mpg on 93 and 19mpg on E85. This is with a fully load of 4 adults and all their stuff on a road trip up to visit my mom in PA. She lives in over by Pittsburgh and in the mountains. So I'm happy with the use of E85 and that little hit to mpg isn't a big deal for me. It might be to some, but pulling up the mountain pass and not having to worry about spark knock is nice.
We do have ethanol free a around us. I would think it is due to being on the coast and boats everywhere. I do use it for all my lawn equipment and in our small boat.