13B Engine PortingWe offer a few different types of engine porting. Street Porting: Gas mileage is typically not affected. Stock turbo(s) and computer works just fine, although some form of fuel enrichment should be used. Advanced port timing gives awesome power through the midrange and spools turbos a lot quicker. This is the port where your idle quality deteriorates. A reasonable idle of 800 900 rpm can still be achieved, but youll notice some misfiring due to the