Yes, I know what the box does, it expands pulse width to deliver more fuel. The problem comes from not having enuf additional injector time or fuel pump/system volume to enrich the mixture properly. Some vehicles have a some reserve, others don't. Of course you could always replace the fuel pump and lines with larger units and increase injector size. Going to higher fuel pressure may also help if the pump will take it. Right now my son's Contour fuel pump and wiring is struggling with the demands that a standard fuel map is placing on it. A chip would be a better solution since you could also increase timing advance but again the reserve fuel capacity must be there. You would also need multiple programs to use varying proportions of E85 and gas unless you had two separate tanks for fuel.