Nightrider XiED Fuel Enrichment for EFI Harley-Davidson Plug - n - Play DK-XiED-NR The Plug-n-Play XiED richens the Air Fuel Ratio from 14.6:1 to 13.8:1 in closed loop mode. Simple install-comes with instructions. No tools required, installs in a few minutes. Immediate Benefits: Lower Engine Temperature - Lower Exhaust Temperature - Improved Throttle Response - Reduced Surging - Reduced Pinging Recommended for: Stock Configuration - High flow air cleaner - High flow exhaust - "Stage 1" (both high flow exhaust & air cleaner) The XiED's are a cost effective alternative to an aftermarket tuner & dyno runs. XiED's will cool your bike down and make it run better