Running alcohol and trying 15% nitro this weekend in my big bore KFX 490. Had the 650cc and hit the limit on it, so upgraded to the 850cc. Now I have the capacity at WOT for the methanol, and a little more room for more, if needed. You need a good fuel controller and a AFR readout to really know what you're doing. I use PCV and autotune. The quad rips!