HAI Experiment

[Jetta90GL]

I don't think by a simple A to B test you can rule WAI or HAI a failure. Since the gains may not be a huge amount in some cases, environmental variables or even driver behavior could taint the results. Isn't the proper method to use averages of multiple trips? Seat-of-the-pants measurements don't seem very conclusive to me.

I do agree that WAI does reduce power, but that is kind of the point. Most times you don't need the full range of horsepower that an engine can produce. The manifold vacuum is reduced and becomes a savings in fuel. Try sucking on a vacuum gauge and see how hard it is to draw a vacuum.

I have felt significant power loss on my truck when I had a grill block creating a WAI. That was back before I knew anything about hypermiling, I was just trying to keep the heater warmer. I was pulling a trailer with an old POS bronco on it, and could hardly get up to speed to merge onto the highway. For this reason if i do create a permanent HAI on my truck, it will have a electric selector valve for near WOT conditions, to draw in cold air.