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Originally Posted by California98Civic
What a great thread! Read through the whole thing, with thanks.
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Thanks! I've been wanting to get some sort of gathering of WAI information together in one place.
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Originally Posted by California98Civic
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.
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I do the same thing. I monitor engine coolant temperature and intake air temperature fairly regularly. I've noticed that the temperature differential is lower as outside air temperature rises. Right now, I'm looking at about a 40 F difference. In the wintertime, it was more like 60 F.
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Originally Posted by California98Civic
That is useful to know. I have always just taken the line I learned from Daox about pumping losses as being the whole explanation.
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I thought the same thing, at first. However, when I first started testing a WAI in the Dakota, I noticed that the manifold pressure never really changed that much, nor did throttle position, yet I was still able to get as much as 6% improvement in fuel economy.
It may have something to do with warm air causing better atomization of fuel, perhaps. Or, as I have thought about over all this time, it could also be that since warmer air is less dense than colder air, for a given absolute pressure, it takes less energy to draw a vacuum with a WAI, than it would with a normal (or CAI). Or maybe it's a combination of both factors.
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Originally Posted by California98Civic
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? |
Your results look good to me. In fact, that post of yours was one of several on this board, that led me on my own WAI path. So, my hat's off to you, sir.
Not sure how throttle position is supposed to invalidate your results, though. It looked like you tried to minimize the variability of other major factors involved (speed, distance traveled). *shrugs* Others here have also duplicated your results.