[ACEL]

Fantasy as the required data to assess the benefit of the modification was not recorded.

Part of my work on the car is looking at newer cars style and devices to compare it with scientific literature and ecomodders experiences, looking for benefitting opportunities. Thus 6 modifications were fabricated in 2019 with little performance assessment on the aerodynamics benefit.

These are
1. Upper grille block with an attempt to streamline
2. Behind rear wheels under belly
3. Air dam
4. Rear trunk lid spoiler
5. Lower side skirts
6. Front spoiler

Some mods are not easy to mock-up with cheap materials like cardboard and tape. In retirement, the available money is scarce. Also, aesthetical constraints and life partner regard on the work done are limits.

Upper grille block with an attempt to streamline

Some aluminum left over from building renovation was modeled to completely block the upper front grille. It was then painted black to match the car color. It was attached at its bottom with two screws in the licence plate holes. At the top, under the hood lid, it was just taped with the "big monkey" fabric tape.

The engine coolant temperature went up from the 70s and lower 80s Celsius to the high 80s and 90s with was intended as an added bonus to the aerodynamics improvement. It seems that engine coolant temperature in the range of 90-95 Celsius is the best for the most complete combustion of the fuel load.

Behind rear wheels under belly

Having some thin aluminum left overs, a sort of rear diffuser was built before the car went out of winter storage. I am no manual worker and certainly not a good craftsman. Pieces were joined together. The whole pan was curved and baling down without enough support. The diffuser angle was in the 1-2 degrees slope at most. The rear car tow hook was hidden and lost. Bad work.

Air dam

As many ecomodders, a 4 ½ inches lawn edging was used to build a front air dam. As on other cars, it was recessed from the front of the bumper cover and almost invisible. It probably brought some mileage improvement that was not seriously assessed. It was replaced by the front spoiler discussed further. Total cost below 10 Cdn$ including self taping screws and sales taxes.

Rear trunk lid spoiler

Looking at 8th generation Civics and Civic hybrid, adding a trunk lid spoiler seemed like a good idea. At first, it was a mock-up. Three layers of 4.5 inches lawn edging were piled up with the next coat rounded edge exceeding the previous, thus building up height but also a rear end slant. Each lawn edging coat was taped with the “big monkey” fabric tape. For a cheap mock-up, it was looking fairly good. It did not pass the aesthetical assessment.

The mocked-up trunk lid spoiler was replaced by a real OEM one from the junk yard. It was taken from a black 8th generation Civic (2006-2010). It remains on the car even though it has not been assessed.

The junkyard cost is 15 $, some two faces 3M automotive tape for moldings and one tube of black silicone caulking were used. About 40 $ and some leftovers.

Lower side skirts

Low budget right material is not easy to come by. Building vinyl siding board for 10 $ was acquired from the hardware store. Strips 3 inches wide, retaining some cornering material, were cut and joined to the OEM existing side skirts with self-tapping screws. It was also painted black before installation to match the car color.

Unfortunately, the siding vinyl board is not a sturdy material. Whether in making the strips or when screwing through to the side skirt some tearing resulted. The material being soft was easily bent to follow the side skirt contour but was also prone to tearing. These side skirts addition lasted the season but one was so badly damaged that both were replaced for 2020.

Preliminary assessment – 1st third of season

Rear section belly pan, air dam, lower side skirts, and deck lid spoiler were combined and resulted in a combined mileage of 7.3 L/100 Km for 2517 Km (32 mpg US for 1564 miles).

The real interesting result is in the whole lot better car stability to side winds and being passed by a truck and box trailer on highway. The car stays the course or requires much less correction than previously.

Front spoiler

Newer cars like Prius, Corolla, Civic, Sentra, Volt and many others have a front spoiler as the lower part of the plastic bumper cover. It may be just a designer fantasy that was copied by competitor professionals at other cars manufacturers or it may have some aerodynamics value. So, I set to fabricate one with cheap building materials available at the hardware store. Pictures attached represent the fabrication process.

The front lawn edging air dam was replaced by this fabricated spoiler at the beginning of the second third of the season.

The styrofoam 2 x 8 x 2 in. thick insulation board was selected for the core. It was than cut in some resembling spoiler shape. Some ½ inch thick window plastic material was used on top and bottom to add strength to the bumper cover attachment. Each coat of material was recessed from the previous bottom one in order to create steps that would allow for a slanted surface when filled with polyurethane foam. The core and strengthening parts were then installed on the car and joined to the bumper cover with 3 ½ inches wood screws.

Polyurethane foam filling the steps and knife sculpting the spoiler to its final shape were the next steps. Not knowing if the spoiler would stay or hold on, the “big monkey” black tape was applied to make it look as good as possible. It seems that air flowing does not care about a very smooth or somewhat rough surface. To this day, by the end of June 2020, the spoiler holds on and awaits the final fiberglass and body filler that will give it the kind of look that will be acceptable.

The cost for this mod is about 25 $ for the styrofoam 2 inch thick core, 60 $ for the white PVC finish for window, 3 polyurethane spray cans for 20 $ and 21 $ for the largest 2 in. wide roll of the "big monkey" black fabric tape. This is all in Canadian dollars, sales tax included.

2nd assessment

But for the replaced air dam, all other mods remain. The car was driven a total of 5723 Km and yielded 6,73 L/100 km in mileage over that period (35,2 mpg US for 3556 miles). Driving conditions and driving style were the same, most of the time with the same driver.

The mileage improvement over the 1st third is 0,6 L/100 km combined (3 mpg US). The second third of the season started with the highest outside temperatures that require the use of the air conditioner. The 2019 mods although not assessed seriously were effective and are to remain or be improved for 2020.

2020 improvements on 2019 mods

Such improvement includes better more rigid side skirts and complete better built belly pan. Also, the front spoiler scrapes badly and gets damaged frequently. If possible the lower white reinforcements coat will be removed. Also the front "air curtains" found on many newer cars seem to have enough merit to be tried on this car and the spoiler will have to be modified to accommodate for that.