15 mods = 15% MPG improvement: A-B test, 2007 Honda Civic 1.8L, 5-speed
 

Some of you may have seen the thread where I was hunting for a winter car to give the Firefly/Metro a break. I ended up getting a good deal on a 2007 Honda Civic LX (1.8L, 5-speed manual):

http://ecomodder.com/forum/attachmen...1&d=1412084540

Since I got it, I've been busy ecomodding it, getting it ready to put in active duty next month.

Before I began modding, I ran a set of baseline speed vs. MPG runs (2-way averages from 70 through 100 km/h). Yesterday, I repeated the speed/MPG runs with all the mods in place (same flat test road, similar ambient temperature).

The mods:

• Increased tire pressure
• 6.5% taller gearing (owing to taller winter tires -- 65 vs. 55 series)
• Reduced tire/fender gap (due to taller tires and slightly greater wheel offset)
• 100% smooth wheel covers (coroplast)
• Civic hybrid style decklid spoiler (CAD ... cardboard... version)
• Civic hybrid style rear wheel spats (coro)
• Full upper grille block
• Partial lower grille block (with pop-out section if it gets warm)
• Licence plate relocation (better aero than the stock bracket)
• Daytime running lights switch (DRL's off when not needed)
• Passenger side mirror delete
• Driver side mirror folded (highway), with convex mirror mounted on trailing edge
• 1 wiper delete
• Vertical spoilers on the rear bumper corners
• Big @$$ air dam (which scrapes now & again)

A-B test results ...

(UPDATE: the chart below has been updated with calibrated fuel consumption numbers. Original chart was based on a ScanGauge with default fuel offset settings.)

http://ecomodder.com/imgs/chart-15-m...calibrated.jpg


That's an average of 15.1% better MPG than stock.


Thoughts/observations ...

- Take this with an appropriately sized grain of salt. It's not a proper "good as possible" A-B-A test under the same day/conditions. I'm not planning to remove/reinstall this set of mods to do an A-B-A.

- That said, I actually ran the "B" 80 km/h pair twice (repeated it at the end), and the 2nd pair of runs produced the same numbers.

- Those MPG figures honestly seem too good to be true: with all the mods in place, the ScanGauge reported 64 mpg (US) at 80 km/h (50 mph). Unmodified, it showed 55.9 mpg at that speed. I'll just have to wait for a fill-up to calibrate the gauge and see how close to (or far from) reality it is. I'll come back and fix the graph if it turns out these numbers are way off. ... UPDATE ... calbration done and the chart above has been updated.

- Though I would think the relative/percent change should hold, regardless of whether the gauge is calibrated or not.

Coming up: I'm going to post a bunch of pics of the mods. See the project thread for some detailed pics of how some of them were made:

http://ecomodder.com/forum/showthrea...7-a-29429.html

pics of some of the mods
 

http://ecomodder.com/forum/attachmen...1&d=1412037852

Above: Air dam, stock (left), ecomodded (right). It's my first classic lawn edging air dam! It scrapes now and again, which tells me it's working. :) There's about 3.5 inches of clearance (and it scrapes regularly).

http://ecomodder.com/forum/attachmen...1&d=1412038465

Above: went from stock alloy wheels to steelies with winter tires which are taller and fill up the wheel well more. I attached coroplast discs by zip tying coroplast bundles to the wheel rim to use as attachment points for the screws through the disc.

http://ecomodder.com/forum/attachmen...1&d=1412038991

Above: passenger side mirror delete. I'll replace this with a much smaller exterior convex mirror (because I often back into tight parking spaces) and a larger interior one also.

http://ecomodder.com/forum/attachmen...1&d=1412037852

Mounted a convex mirror on the trailing edge of the driver's outside mirror (for highway use).

http://ecomodder.com/forum/attachmen...1&d=1412037852

Added hard "corners" to the rear bumper in the form of vertical spoilers to promote clean flow separation, as on many newer, aero-focused cars (e.g. Volt, Prius, Mitsu Mirage).

http://ecomodder.com/forum/attachmen...1&d=1412037852

Copied the Civic hybrid deck lid spoiler, left. My cardboard test version is just a little bit taller than the hybrid one. I'll reproduce it in coroplast for the winter.

http://ecomodder.com/forum/attachmen...1&d=1412037852

Also copied from the hybrid: rear wheel spats.

http://ecomodder.com/forum/attachmen...1&d=1412038200

Above: showing the stock grille and front plate bracket (left), grille blocks & plate relocation (right). The lower block has a quick-removable section in case things get warm.

Nice mods on a nice car :thumbup: but I'm going to need you to go back and run an ABA on each mod, and various combinations of mods:D For example, I've thought that my rear wheel skirts might not have shown the improvement I'd hoped for because my rear bumpers corners have the radius of a beachball.
What can you tell me about the construction and attachment of the vertical spoilers? Is it in a hopefully permanent version, or will there be a 2.0?
Also interested to see the trunk spoiler come out of beta testing, I've considered chopping my (currently removed) spoiler down to the width of the trunk lid, but still in fear of mutilating it enough that a handmade spoiler would look better

I think it should be fine... just need to get that Scangauge calibrated. Last time I drove a 5-speed like that, I think it did around 19 km/l at 80 km/h (tank-to-tank)... but that was with some tollway traffic... so I think 20-21 km/l would be more representative of stock conditions.

Would be amazing if you really could touch near 3 l/100km with that car! Love the detail work on the decklid spoiler and bumpers!

Best morror mod ever.

HA - not gonna happen!

Since I'm only keeping this car for the winter, there won't be a version 2.0. Construction: it's just coroplast, duct taped on. :)

I'm just going to replicate it in coro and tape it on. But that style of spoiler would be pretty easy to make with rigid insulation foam board -- I'd put in the time to do that if I were keeping the car.

I probably won't have to fuel this car up for a couple of months, so I'm going to ask fellow ecomodder member & Civic owner Philscar (who lives near me and has exactly the same Civic) to calibrate it on his car.

Thanks! That was with a 1.8L?

19 km/L = 45 mpg US = 5.3 L/100 km
21 km/L = 49 mpg US = 4.8 L/100 km

The 2-way averaged constant speed runs I do are typically a little higher than an actual highway trip at that speed. But going by your numbers, it seems like my uncalibrated gauge may be ~10% optimistic (going by the 21 km/L end). I'll ask Phil to calibrate and will report back.

Yeah... that sounds about right. Damnit. Should have thought to calibrate the fill-up against the gauges on that eco-run!

Then again... that was a single data point with a very small fill-up, so it could be as low as 5% over... and I only did half the driving... (we swapped cars during the run), so it could be even better.

Still... seeing the lip spoiler and rear kickers... that gets the gears grinding on what might be possible on future experiments...

I dropped off the Scangauge to Phil. He figures he'll have some calibration numbers in about a week.

Should we start a pool? I'm guessing my graph numbers are 12% high.

UPDATE: calibration over 4 fill-ups showed the gauge was optimistic by 9.3%. Chart in post #1 updated with revised numbers.

Oh come on Metro, you should know without proper A-B-A testing this belongs in the Unicorn Corral. (;

Otherwise, my roof rack delete is worth 40%, cause I got that better mileage that one time I got on the highway instead of driving up my dirt mountain path.