For ram air to work you need to be going well over 55 mph to even consider it actually working. The only reason you increased speed was you provided a better fuel mix for your engine. Which tells me your carb wasn't tuned properly to begin with. Turn your carburetor around so it faces the rear with your ram air set up and I bet it does the same speed as it does when you have it facing forward. A properly tuned air fuel mixture will add speed every time.