Winterizing Figgy's California Insight

Do No Evil

My first and foremost goal is to 'do no evil' by which I mean doing anything which will damage the little bundle of joy or shorten the little bundle's life expectancy. I neither want to permanently alter anything I can see, nor do I want to mess up innards which I can't see such as the engine, cat converter, etc. etc.

Diurnal Denizen

Having set do no evil as my first priority, I also have a very high priority to make all the cold weather mods not so much seasonal as diurnal. Here in Northern California the winters are cold enough to zap mpg, but on any given winter day you might see a jump of 40 or even 50 degrees from night temps. A common pattern is for nights to be in 40-50s and days to be in 60s to 70s when things are nice, or 30-40s at night and 50-60s in day when things are more chilly. In summers those kind of huge differences in day and night temps can be even greater. Not to mention the microclimates here where you can go from hot to cold in no time just by driving a little bit. The beach may be 50, but on the other side of the mountain it's over 90. It sure would be nice if Honda had made the CAR actually FIGURE THIS OUT! A little bone to pick with them...

Getting back to the point, when I was driving at night or in the early morning hours when it was still cold, I was seeing 20 to 30 mpg drop off from driving in the day when the weather was up in the high 60s and 70s. It's always better to avoid traffic by making trips in the wee hours, but the Insight was changing that because those times were not giving decent mpg. Not acceptable. I needed something to let me drive whenever I wanted, without losing fuel economy in the process. Ideally it would be something that I could take on or off easily, or leave installed all winter and only bring out as needed during as summer cold snap or a trip to a cold microclimate.

TEST 1. Cardboard Tested and Rejected

My first test from reading the boards was to do the cardboard over the radiator trick, and it helped when I placed cardboard over the AC condenser on the passenger side and at times over the radiator portion of the AC condenser, but it was clear that cardboard wouldn't hold up in the rain. The other problem with cardboard placement directly against either the AC condenser or the radiator itself was that I worried about having the fans come on and suck against the impermeable wall of the cardboard block. With AC coming on in winter for defrosting, it didn't seem a good idea to totally block off air flow over the AC fan. Similary, in case the engine was for some reason feeling hot and turning the fan on, having the radiator fan completely blocked off wouldn't be good either. The tests with cardboard helped me out getting back to lean burns in the colder weather/night temps, but it wasn't a long term solution.

Other folks have reported blocking off the lower air intake grill from the outside as a cold weather modification, and they reasoned that doing that blocked cold air from blasting over the engine, but it still left the ability for the AC and radiator fans to both pull in air if they turned on. It also would help aerodynamics to push the air around the car, rather than having it ram deep into the grill cavity and then hit a cardboard or other interior block and get pushed out or sideways. This led to the current solution...

TEST 2. Foam for the Frugal

I started another quest for putting erstwhile garbage to a renewed purpose. I turned to some old leftover foam floor matting. It has turned out to be the perfect solution for a light weight, easy to remove, non damaging, cosmetically neutral air block for the lower grill. I got it years ago at Home Depot for a project, and I haven't seen it since then, but it must be available somewhere still.

Foam cut to size for wedging over lower air intake grill

Insight with foam wedged over lower intake grill

The foam is very resilient and is stiff enough to not collapse when it is bent, so with a little trimming it was easy to come up with pieces sized to wedge right into the gap in front of the grill with enough friction holding them to keep them from popping out from compression or from wind flow at highway speeds. There is some lip along part of the grill area which helps further to keep the foam pieces in place. I also made some back up pieces and other shapes, so that I can do partial blocking if I want to in different weather conditions.

Road Results

With just this mod, I was getting more lean burns at up to about 50 mph in 40-50 degree weather, but I was still not seeing mpg and lean burns like during daytime driving in the high 60s or 70s. It helped the car warm up noticeably faster, but wasn't enough for the highway or sustained 50 mph.

TEST 3. Metal Mania

A test drive with carboard over the AC fan area, and the foam lower grill block in place gave me what I wanted for 50 mph driving. I pulled my mileage back up to 98 mpg on my intersection free test road. It's a road in good repair with mild ups and downs, but no major hills and no stops all posted at 50 mph. I made an all weather modification to the cardboard piece by wrapping it in 14 inch flashing from Home Depot. The flashing is too flimsy to stand by itself without flapping and making noise (didn't even bother to try it driving), but when I wrapped it around a cardboard core it was perfect. Stiff, water proof (taped at edges and sealed, fire resistant too. I spray painted the top black so that would not show, and cut a notch out to make it fit perfectly over the AC fan area.

Metal plated cardboard and Bankers Clips


Clipped in place

Bankers Clips

I got these Bankers Clips at Office Depot. They are the perfect tool for clipping cardboard or anything else to the AC condenser unit. Their widest width is just right, and they spring on and off easily without trouble. They also have a long reach, so they clip down 4-5 inches on either side of the grill to help give stability against any vibrations or wind pressures for the blocker.

A A little black paint needed for the Bankers Clip...

TEST 4. Foam Finale

While the blocker over the AC fan area on the AC condensor seemed to work well in bringing back lost mpg, I still didn't like the idea that the AC fan was flat up against a dead surface and wouldn't be able to operate properly for defogging. If I cut holes in the blocker, it would let the fan pull air, but it would be letting cold air throgh to blow over the engine behind. It would still be a pretty direct path for cold air to get back to the engine. I went back again to the idea that the fans should be able to both pull air if they turn on (increase air flow when on) and to try to block air closer to the entry point and came up with this foam mod.

A Foam cut to fit and be fixed with the Bankers Clips...

A Foam clipped onto the AC condenser

A Close up of the Bankers Clip...

A Close up of the Bankers Clip...

A Finished. Black paint needed for Clips...

Rationale Driving this Mod

My idea here is that I want to block excessive cold air flow over the engine, but still allow the AC fan good draw and the radiator fan air flow if it pulls for it. To get this, I used the knobby edge of the foam matting to leave space up against the AC condensor, and I left gaps at the right and left edges to allow air to flow around and/or down. I also left open space above the level of the insert so that there would still be plenty of fresh air coming under the hood for combustion air..

Road Results

With this mod and the low grill block, I got back again to mpg in the 90s for the test road at 50 mph. I also saw some lean burns at 60 mph, but still not quite as good as in warmer driving temps. Engine warmed up quickly. I did not do a lot of city driving with this yet, but I have not seen any sign that the engine is running hot and I haven't had the fan on when stopped and idling (not auto stopped, gas engine running at idle).

Remaining Questions

This makes a kind of air pocket around the air temperature sensor behind the grill, and after driving it for a while the AC condensor in front of the radiator becomes ever so slightly warm and the radiator gets slightly hot to the touch (but still easy to touch and even press one's finger upon for a few seconds without serious discomfort). I am sure that there is a pocket of warm air here around the front sensor. What is the result of that?

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