Just installed hot air intake

[crx_rogus]

I use a 3" diameter home HVAC T-fitting from Home Depot, aluminum, strapped to the convertor with a cut-up large coffee can as a back shield to maximize heat transfer as the heat intake, all thoughly clamped on (no steel:Al corrosion yet). I use 3" aluminum home HVAC duct flex from there across behind the engine, under the battery, over the 3-phase IMA power lines and into the air filter box.

I use old socks with the toe sections cut off slipped over the tubing for insulation and for flex/vibration damping and protection.

On the highway in 70 deg. ambient temps I see 120 - 125 deg. intake air as indicated by my ScanGaugeII. In trips to the grocery store etc. upon firing the car back up again the convertor's still fairly hot, helping the engine warm back up again fairly quickly via hot intake air. In 25 deg. winter temps I'd eventually see 55 - 70 deg. F intake temps. in my 7 mile work commute, with the coolant temp about 2X the intake air temp. (I used a full radiator block, and the 12V seat heater listed in my sig is for minimizing heater needs.)

I prefer 3" tubing to minimize air restriction (if the sides were smooth I could go narrower). I also wanted to maximize intake air volume to miminize the sharpness of intake temperature swings. There isn't alot of space for an external air mixer that doesn't ask the intake air to do a sharp 90+ degree turn, which at WOT would reduce power. So, JoeCVT, while I greatly admire your automatic intake preheat, I'm wondering if maybe a flapper valve inside the filter box, with a cold air intake hole next to the existing intake hole, and the flap (hinged between the two holes) covering one or the other as needs dictate would minimize air restriction. Cutting a big hole in the OEM filter box isn't ideal of course, but for minimizing sharp intake path bending I can't think of anything else. Hondas tend to have meticulously engineered aerodynamics from their bumpers to their engine air intakes, and I really don't want to possibly interfere with that. (The original utterly silent intake via a narrow intake tunnel and resonance-dampening had to go though... PGM-FI's lack of a mass airflow sensor means WOT should be a useful 2nd horn, perfect for safely warning bicyclists.)

[joecvt]

Originally Posted by crx_rogus

There isn't alot of space for an external air mixer that doesn't ask the intake air to do a sharp 90+ degree turn, which at WOT would reduce power. So, JoeCVT, while I greatly admire your automatic intake preheat, I'm wondering if maybe a flapper valve inside the filter box, with a cold air intake hole next to the existing intake hole, and the flap (hinged between the two holes) covering one or the other as needs dictate would minimize air restriction. Cutting a big hole in the OEM filter box isn't ideal of course, but for minimizing sharp intake path bending I can't think of anything else. Hondas tend to have meticulously engineered aerodynamics from their bumpers to their engine air intakes, and I really don't want to possibly interfere with that.

I don't think 90 degree turns matter too much as long as you do not break the bend (link kinking a water hose). The stock inlet piping has many turns and shape changes with a couple of 90 degree bends.

I have read your thoughts on restricted air flow in my setup and I tend to disagree but let me explain why and perhaps I may sway your opinion

The part that I used for the air mixture is the snorkel portion of the air cleaner from a 1984 Honda CRX. This cutoff snorkel portion contains the vacuum valve and gate (flap) to allow a mixture of cool and hot air. On the 84 CRX, the hot air came from a metal shield around the exhaust manifold via approx 2 inch tubing.

Now with that original 1984 CRX part, I attached tubing (hoses) to the outer portion of the hot and cool inlets meaning that the most restrictive orifice is the actual metal port from the air mixer.

Nowadays, the hot air still comes from a modified metal shroud around the catalytic converter (so basically the same method as the CRX) and cool air comes from just under the hood to get a little ram air effect (just a little).

Now here is my point. A major air flow / mixture part of what I setup in my Insight is from an 84 CRX that had a 1.5 liter engine. This engine was the performance model compared to the 1.3 liter HF CRX version so my guess is that Honda had the proper setup for adequate air flow for the 1.5 liter. I am now using the same part for a 1 liter engine and due to its reduced engine size, the air intake demand is only about 2/3 of the capability (performance) of this part that I am using. It should be able to pass more air than the Insight can possibly take in using the stock throttle body.

Hopefully that makes sense or maybe I'm just full of hot air

Did you take pics of your setup. I would like to see your connection to the cat area?

JoeCVT = Just your average CVT owner

[Need4Speed]

What is the diameter of the stock throttle body?