I've got a 06 Corolla with an AT and fashioned a WAI that is just a a 3" flexi-pipe run back by the exhaust manifold, then attached to a sheet metal shroud to draw pre-warmed air from that area. It works, but I only get a boost of about 15 degrees above ambient during my 35 mile one-way commute at freeway speeds.
Misc points:
- AFA hooking it up to the present snorkel arrangement, I removed the final elbow and just have the flexi-pipe stuck over that.
- In town it works OK, I get a boost of about 40 degrees. I'm thinking one problem with the present set up is the length of hose from the exhaust manifold to the Air box; probably a five foot distance. With ambient temps in the single digits, I wonder if this is preventing the temps I'd like.
- Thought about trying a WAI intake directly from the radiator. Possibly by taking the plastic shroud off the radiator, then removing some of the plastic to accommodate a shroud/hose, and putting it back on.
- I like the idea of the put-a-hole-in-the-bottom-of-the-air-box. I will probably give that a shot this summer (too cold now!)
- Current mileage is about 35/36 in the winter, 42 in the summer. Tires are at 42 psi, I have a partial grill block, and guessing a 80/20 split on highway/city driving. Radiator block gets my water temps up to about 195 degrees vs the "normal" 181.
- Temps monitored via a Scanguage, not sure how accurate that is....
That's about it for me, good luck to all!