[California98Civic]

What a great thread! Read through the whole thing, with thanks. Some confirmations and a question:

Originally Posted by t vago

The intake heater, as installed, appears to give a reliable 45 F delta T between the outside air temperature...

My WAI has tended to give me 30 degrees F over ambient. I have loosely observed that many times driving around listening to radio weather reports, public temp displays, and observing my IAT sensor readout on my ultragauge.

Originally Posted by t vago

Part Load Pumping Losses in an SI Engine ... Changes of Low Load Engine Parameters by Temperature of Mixture

I think that this paper is showing that the resulting gain in fuel economy from installing a HAI is a combination of the two factors.

That is useful to know. I have always just taken the line I learned from Daox about pumping losses as being the whole explanation.

A question: I did a WAI test myself two years ago on my MAP equipped Civic. The results confirm yours, though my IAT and FE gains were not as great. But had to use steady throttle position in the place of cruise control since I do not have CC. I saw a modest increase in what I thought was a fairly rigorous DIY test, but it has been suggested to me that using throttle position invalidates the results. [Here are the results. Any thoughts on the validity of my test?

Thanks.