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.

Okay. The zip tie coroplast bundles as mounting points for screws through the smooth wheel covers is a very clever solution. Nice hacking, that.

That result seems pretty good... about 65 mpg is what I see on my first gen civic hybrid on level ground at about 50 mph.

It's already got some of the aero mods you did from factory (decklid spoiler, underbody smoothing panels, upper grille block, sort of aero wheels) and a smaller engine (1.3L), so that seems about right.

Also, manual transmission ;).

Sam

Err, how do you know they are not needed? When you get home and not having them on you avoided an accident? In that case how about a switch for the SRS and the brake actuators that are responsible for trac, skid, abs and the brake force thingie.

Samwichse: I'm guessing that when the ScanGauge is calibrated, my numbers will be revised down some. Even with all the mods, I doubt this car is as efficient as a 1st gen Civic 1.3 with lean burn.

Cobb: DRL's are next to useless on a limited access, divided highway. In town or on a 2-lane highway is a different story. So I like to have the option to choose when they're on or off, depending on the driving situation/environment.

That's called "Operator Prerogative" :thumbup:

Roi
 

Also worth mentioning:

The cost of these mods was about 2/3 of a sheet of coroplast, a bit of duct tape, a couple of convex mirrors and 5 feet of lawn edging (had some laying around). So let's say, generously, $20. *

Reasonable payback time!

(* Not counting the $150 used set of winter tires on steelies, which I needed and would have bought anyway.)

Good improvement! I like how most of these modifications are minor and subtle. The lip under the front bumper looks nearly factory, those mirrors I think you might have been able to get away with double sided autmotive adhesive (same thing used to hold the side door trim panels on the exterior of the car) instead of drilling holes. The covers look factory too and actually give the car some flair over those factory alloys

I know you mentioned it in the other thread but why are you only keeping it for winter?

DRLs have been one of my pet peeves since they came out. Before we realized how vital lights were for safety, we had these things called switches that could turn our lights on and off. Call me a rebel, but I still like to operate my lights on my own.

Possibly, though it'd be sticking a flat disc on a compound-curved surface. Not much contact area for something that has to resist hurricane force winds.

Also, the holes are on the bottom of the mirror housing. Can't see 'em when the mirror's deployed in its normal position, so it didn't bother me to drill there.

Couple of reasons:

1) Mostly because I got a pretty good deal on the car, and should be able to sell next year and recover all my costs (inspections, repairs, gas, registration & insurance) and maybe even make a few bucks on top.

2) I think I've discovered it's fun looking for winter beaters. I'll hunt down something different next year. Maybe even make it an annual tradition.

Hey, I'm just citing you.

:D

PS: you should make a garage entry. Add new vehicle

I have just joined this forum, it looks very interesting.

Can I ask what material you have made your front air dam out of? It looks rubbery but I presume it must be fairly rigid.

The car looks good, I have a 2002 SEAT Leon 1.9 TDi so am looking to improve the warm up time when it starts to get a bit colder. I am in the UK so it doesn't get too cold and I already get 54MPG average (UK = 4.55 Litre per Gallon). I would like to get it nearer 60MPG which is why I am here.

Lawn edging, it costs 6 bucks at Wal Mart.

Ah I see. Brilliant. So yes, I presume it is slightly rubbery and also fairly rigid.

Hopefully I can find a similar product in the UK. Thanks very much.

Hi, aymen_a22.

The garden edging I used is more "plasticky" than "rubbery". Moreso than the factory airdam material. Fairly rigid, yes.

Calibration update:

FYI, it appears the numbers I posted in the original graph are about 10% optimistic based on my first fill-up against the ScanGauge and a short fill that Phil made with his '07 Civic 5MT. I'll wait for 1 more set of numbers and then will correct & re-post the graph.

But the relative (percent) difference would be the same

Another thought is look at finding a wrecked Hybrid and pull the under carriage aero panels off. There was a member on the board who bought a set for his Civic off the dealer and saw a nice jump in fuel mileage.

Other than that nice work. :)

Thanks - and yes, I'm considering it (DIY with coroplast, though).

This '07 has a few factory underbody panels (including a full panel filling the space between the rear suspension and the back bumper) but it could be better.

2007 Civic Testing
 

I don't know if you used a GPS to record you distances, good to calibrate your Odometer with it. Good Luck :)

Paul

Hi Paul -

I entered a correction factor for the speed/odo in the ScanGauge due to the different tire circumference, but I haven't verified that the original readings on the original tires were accurate.

The relative difference in MPG should be the same though (% change as a result of the mods), even if the absolute numbers are off by a bit from reality.

Darin

How are those coroplast mounting blocks holding up on your fancy wheel covers? I've got two sets of alloy wheels and am thinking about how I'm going to mount covers on them.

So far, so good!

But I haven't put a lot of miles on the car since I did that. Maybe 400-500 km.

It would be useful to check odometer now with GPS to see how accurate it is with ScanGauge.

Paul

grille block
 

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

Today someone came up to me and asked: "Why do you have so much of your grille blocked off? Doesn't it overheat?"

So I got the chance to explain some aero. I always mention "worst case" cooling design and active grille shutters showing up on more & more vehicles.

Fact is, I haven't heard the cooling fan come on yet, and we haven't even had sub-freezing temps (where the car will be happier for the retained heat).

Thank you and subscribed.

Calibration = chart updated; new spoiler
 

FYI, calibration the gauge, it came in at 9.3% optimistic based on 4 fills. I've updated the chart in post #1 with the revised MPG numbers.

---

And...

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

Also, I've replaced the cardboard imitation hybrid-style rear spoiler with a coroplast version:

http://ecomodder.com/forum/attachmen...1&d=1415286993

More spoiler pics in my Civic project thread.

Metro, how did you do the mirror delete? I noticed its door mounted not up on the A-pillar triangle. No mirror heater or indicators to deal with? What did you use to hold on the fillet piece. I'm so close to talking myself into it.

Hi kafer65 -

I had to pop off the inside door panel -- not too complicated on this car. The mirror does have heat, but there's a wiring connector close to the mirror, so I just popped that apart.

Three bolt holes and one slightly bigger wiring hole were covered with a piece of black tape. I still haven't made up my small external convex replacement, but will get to that eventually.

Nice mods.

Is this an LX or EX?