When you have 10% of anything it WILL run worse if everything isn't set up for this fuel. Be it methanol, benzene, toluene, nitromethane, hydrazine (don't go there), or whatever there is a thing called stoichemistry that says a fuel must be mixed with the right amount of air to work. This along with correct heat range plugs, timing, and compression suitable for that fuel are all needed to get results desired. Just pour it in and go doesn't work.