That is unfortunate, I had false knock when using he 91 fuel, I did mix 100 with 91 and the knock was gone for those 2 logs but it was a hassle and pricey. you will probably be limited to boost due to the fuel. Alex from Lund tuned my car. Theres a mustang shop in simi valley with a dyno, addiction motorsport and rented their dyno. thats where i did my logging for E85