March 22, 2008 - Added a Warm Air Intake
I wanted to wait until I was happy with this WAI before posting pics etc. so this is a belated post. Let's get straight to the pics:
The inlet is a $5.29 flexible steel exhaust tube from an auto-parts store. Its is approx 2-1/4 in diameter. I tucked it just under the exhaust manifold shroud, but I was careful to make sure it was not actually touching anything. It is zip tied firmly onto one of the fan shrouds. I also slightly rearranged the O2 sensor wire so it was not touching the inlet.
The coupling is a 2" plumbing coupler from Home Depot. This costs around $2.99. Be sure to get one that is safe to use with hot water, so it will withstand higher temps.
The filter box for my particular engine (D16Y7) is uncommon for Hondas. The filter is inside a box with a downward facing throttle body... kinda like a carb intake that was converted to fuel-injected. I have asked around, and it has been agreed this was designed for fuel efficiency, better emissions, and low end torque improvement. In any case, this particular manifold is well-suited for conversion to a WAI. I simply sawed it off short, removed the sound-dampennig box, and put my flexible inlet on.
This mod has been the biggest improvement I've seen outside of changing my driving habits. I'd say its around a 10% FE improvement, and with my driving style changed, I haven't noticed the accompanying loss in horsepower at all.
With intake air temps averaging 140°F I'm still wondering what this will do to my spark plugs and sensors. I'm also getting an itch to pre-warm my fuel...any thoughts?