I did exactly the same setup as the scion in the pics but on my 07 yaris, and the results were virtually no dif, lots of extra heat in the intake but the computer decides everything and thats all there is to it.
You can do anything you want that should make a dif, but the computer will over-ride it all. Thats why i sold the yaris for a 92 VX. At least its designed to get better MPG from the get go.
Well, I did my ABA testing with the insulated WAI today. Ambient air temp was 66 degrees when I left the house. 9.7 miles of P&G later, I arrived at my testing area, with the xB warmed up. Water temperature (FWT) was 195 degrees, intake air temperature (FIA) was 100 degrees, and my mpg for the drive out was 52.3 mpg.
First, I did a B test, since I had the WAI hooked up over the exhaust manifold. I reset the Scangauge, got up to 31 mph in 5th gear, set the cruise control, and let her run. 19.3 miles later, I averaged 54.0 mpg. FWT was 202 degrees, and FIA was 127 degrees. It got as high as 138 degrees climbing one hill, and was at 130 degrees most of the run. This was a 30 degree improvement over the uninsulated WAI from earlier testing, and about 60-65 degrees over ambient temperature.
Then I did A testing, routing the WAI off the exhaust manifold and back behind the radiator, simulating the OEM air horn position. My WAI did its job during the earlier test. The FIA display during the A run ranged from 91 to 96 degrees during most of the test, 31 to 47 degrees lower than temperatures from the WAI position. FIA during most of the run was 94 degrees, an average of 36 degrees cooler than the WAI B run. But what mpg did I end up with? At the end of this A test, FWT was 202 degrees, FIA was 94 degrees, and my average mpg for this 19.3 mile drive was 54.1 mpg, nearly identical to the previous run.
I switched back to the B (WAI) position and did another test. At the end of the drive, FWT was 204, FIA was 127, and mpg was 54.1, identical to the OEM simulated air intake position. Ambient air temperature might have increased 5 degrees during all the testing. I left the windows cracked during all tests, and never needed to run the AC. Wind was minimal, under 5 mph during all testing.
I P&Ged back home, with the WAI in B position, averaging 61.4 mpg for the 9.7 mile drive, with FWT at 195 degrees, and FIA at 114 degrees. P&G is pretty easy on engine temperatures and much better for mpg.
I think I can now make the statement that, based on scientific, controlled testing, a WAI provides no significant mpg difference in my car. Coupled with Darin's results at metrompg.com, the two best scientifically controlled WAI tests show no benefits from WAIs. Now the burden of proof falls on those who claim WAIs work in their cars, to do similar testing to prove it.