Can't Get Good Fuel Economy - 2008 Civic Manual

[whatjigg]

Hello Everyone,

I've been tracking my fuel economy in the last three months and attempting a number of the different hypermiling techniques and seeing very minimal changes (maybe even changes that are not statistically significant). I drive in Ottawa, ON, Canada and the car is rating at 5.4L/100Km Highway and 7.4L/100Km City, and 50/50 Mix of 6.4L/100Km. My goal was to get within 10% of these numbers or match them.

I established some baselines back in August when I began doing this. I always fill up at the same station and same pump number (#5) with the pump nozzle pushed as far in as it goes and fill up to automatic stop level (i.e. no topping up). Below you will find the three months worth of results I've had with the notes on the side indicating what type of changes were made.

As per changes in driving habits, I have followed, for the most part, these suggestions: turn off engine at long lights, pulse & glide, glide down hills and use the terrain to my advantage, drive like grandpa but slower (never exceeded 87km/h on highway and usually aim to drive at 2000rpms), shift points at 2500rpm or less and w/out lugging engine, drive like i don't have breaks and avoid full stops (rolling stop signs),and later on keeping the windshield venting off as much as possible along with other in car accessories just in case.

Summary of my results:
Average Fuel Economy: 8.55L/100Km
Average City/Highway Mix: 47% City / 53% Hwy
Weighted Percentage Above EPA (taking into account city/hwy mix and expected city/hwy mix weighted): 35%
Average Improvement of Fuel Economy w/ Hypermiling: 3-4%

And here's all the data:

Date Fuel Distance Fuel Economy City Highway Weighted EPA Goal % Above EPA Notes

12-Aug-08 26.732L 283.2Km 9.44 L/100Km 65% 35% 6.7 L/100Km 40.88% Baseline Reading

17-Aug-08 20.889L 277.6Km 7.52 L/100Km 20% 80% 5.8 L/100Km 29.74% Baseline Reading

22-Aug-08 7.720L 112.3Km 6.87 L/100Km 20% 80% 5.8 L/100Km 18.52% Tire Press. ↑ 37psi; Pulse & Glide; Engine Shutoffs; Speed Limits;

01-Sep-08 10.115L 108.1Km 9.36 L/100Km 50% 50% 6.4 L/100Km 46.20% Never exceed 87km/h, drive like grandpa, + all above

5-Sep-08 17.294L 183.9Km 9.40 L/100Km 40% 60% 6.2 L/100Km 51.68% same techniques

12-Sep-08 15.000L 154.3Km 9.72 L/100Km 75% 25% 6.9 L/100Km 40.89% same techniques

21-Sep-08 33.476L 483.0Km 6.93 L/100Km 10% 90% 5.6 L/100Km 23.77% same techniques

24-Sep-08 13.273L 137.4Km 9.66 L/100Km 50% 50% 6.4 L/100Km 50.94% normaler - shutoffs for long delays, lower rpm shifts, 87Km/h max

30-Sep-08 29.121L 396.2Km 7.35 L/100Km 20% 80% 5.8 L/100Km 26.72% normaler - shutoffs for long delays, lower rpm shifts, 87Km/h max

6-Oct-08 36.549L 528.7Km 6.91 L/100Km 15% 85% 5.7 L/100Km 21.28% all techniques employed

11-Oct-08 16.885L 176.5Km 9.57 L/100Km 80% 20% 7.0 L/100Km 36.71% all techniques employed

17-Oct-08 22.374L 235.9Km 9.48 L/100Km 95% 5% 7.3 L/100Km 29.93% all techniques employed

3-Nov-08 38.332L 533.1Km 7.19 L/100Km 10% 90% 5.6 L/100Km 28.40% more 'normal' as above

10-Nov-08 12.499L 131.2Km 9.53 L/100Km 85% 15% 7.1 L/100Km 34.18% all techniques employed

17-Nov-08 16.174L 172.8Km 9.36 L/100Km 65% 35% 6.7 L/100Km 39.70% Stopped windshield heater and min. use of features, + all above



Please let me know what you think. I even brought the car into service at the dealership to tell me what they think and to take a look at it. I'm convinced they didn't look at anything. I'm very interested in comparing numbers if you also have an 06-09 Civic along with driving techniques.

Do you think:
- Resetting the ECU will help?
- Adding a cold air intake?
- Other???

Thanks again, Cheers!

btw, i've also posted the same post on hypermilingforum.com

[KJSatz]

I drive the same car but in the US. Does your car have the hybrid style wheels and spoiler on the trunk? I think some Canadian dealerships made those modifications to improve the fuel efficiency numbers. If you do, consider yourself lucky, because I'd love to have those built-in aeromods.

The only physics change I made to my Civic was upping the tire pressure. Over time I tried 36psi, 38psi, 40psi, and most recently 44psi, the max sidewall rating on my tires (your tires may be different if you have the hybrid tires, so double check). This makes a big difference. I don't know if you use SI units of pressure, and if you do those numbers won't be helpful, but starting off with something between the pressure recommended in the owner's manual (for me, 32psi) and the max sidewall (for me, 44psi) would be a good place to start.

What techniques are you using to drive? I have substantially increased my fuel efficiency in my Civic by shifting around 2500-3000RPM and not accelerating aggressively. I coast in neutral as much as possible. In city driving, I have found the Pulse and Glide technique to be very useful. I go to my target speed, shift to neutral, and coast for as long as possible. Also try to anticipate lights turning so you won't do a "Pulse" right into a red light. If you have a stop coming up, use engine breaking (keep RPM above 1500RPM to ensure the fuel injectors are cut off, and of course have your foot off the accelerator). In general it is better to coast in neutral if you can start far enough back. On the highway, keeping speed under 60MPH or 100km/h is very beneficial, both due to drag and the unfortunate fact that our 5th gears aren't very low. Shift into neutral down hills. Avoid cruise control (even in flat areas, I think our cruise control uses more fuel than it needs to). In cruise, try to use as little throttle as possible, to encourage the engine to enter "fuel efficiency mode" which you can read about here Technical Overview of Honda's new R18 i-VTEC Implementation and here Honda Worldwide | New 1.8l i-VTEC Engine . Minimize AC, heater, and fan usage.

I have been able to exceed 45MPG on highway trips which is about 3.8L/72km which is about 5.3L/100km. I also haven't changed my oil yet from the factory oil, so I anticipate that when I do that efficiency will improve. I know you already know most of what I said here based on your post, but hopefully you can glean some insight from this. I'm happy to answer any questions and glad we have another 8th-Gen Civic MT on the boards!

[whatjigg]

Hi KJSatz and thanks for the pointers & tips. I have been doing most of what you've said above and some to an even higher degree. My shift point is now 2400-2500RPM, no higher and on the highways I don't go any higher than 87km/h = 54mph.

Now what I am very interested in learning more about is this 'fuel efficiency mode' you mentioned and that i've seen here/there around forums. And as per my vehicle, yes the 08's were tweaked in Canada to meet the ecoauto gov't rebate program. For my car this meant some further engine tuning to do with gear ratio's i think and maybe some other minor changes, a lip spoiler (yes I agree, it's so small yet add's so much to the look of the car), and some undercar improvements to aid aerodynamics. And no, I bought the LX model with the alloy rims & power everything (DX-G model and hybrid have the flat wheel covers).

Now if i compare my fuel economy to yours, I'm about 2mpg above your highway FE.

Any ideas w/ respect to resetting the ECU? I've read posts saying it does a lot and others saying it does nothing but won't harm anything.

[MetroMPG]

Hi whatjigg -

Do you have a ScanGauge? If not, before anything else, that's what I would recommend. Just going tank-to-tank offers little usable information in terms of feedback to your driving style.

If I were still in Ontario (1000 Islands), I'd offer to meet with you to do a driving clinic. But I'm on the east coast for the winter. I bet by the spring when I get back you'll have this sorted out!

[MetroMPG]

Oh: Another extremely important factor to consider is that as the weather gets colder, your fuel economy will drop, all else being equal.

EG, see: 9 reasons why your winter fuel economy bites! - MetroMPG.com

The fact that you were able to achieve the exact same fuel economy in your first reported tank in summer conditions, above, as well as your most recent tank in early winter mid-November means your driving style has effectively improved your fuel economy.

[Ford Man]

Try lowering your shift points a little more if you can without lugging the engine. I drive an '88 & '97 Ford Escort and I usually shift at 2000-2250 RPM. I've found out that about 50 MPH cruising speed is a sweet spot in my '88. I'm averaging between 44 & 45 MPG on both cars, but the '97 has been about 85-90% highway miles. I'd also run the tire pressure up to sidewall max. I always coast down hills (no acceleration) that are big enough to maintain my speed and just as I hit the bottom of the hill I start to accelerate before I lose any speed or momentum. If you are coming up to a red light slow down enough to try to keep the car rolling until the light turns green and other cars get started and out of the way. I've read that it takes about 20% more fuel to start from a dead stop than it does if you can barely keep the car moving. A Scan Gauge will also help you learn your car. They are about $150. US and give you lots of information. You'll be able to see in real time what effects different driving habits have on FE. Plus it can tell you water temp., charging voltage, RPM, MPH, engine load, throttle position, current MPG, tank MPG, trip MPG, gallons used per hour and there are other gauges plus you can program in some of your own in the X gauge feature (up to 25 or 26 extra gauges I don't remember which) and it can also scan the ECU and give you any trouble codes if the check engine light comes on. I bought one back in the summer and have really enjoyed using it. If you are interested in buying one you can go to CleanMPG, An authoritative source on fuel economy and hypermiling and join and they usually have a group buy where you can get it for $150. Hope this will help you some.

[MetroMPG]

FYI Ford Man, EM has the same group buy deal: http://ecomodder.com/forum/showthrea...info-2469.html

But Canadians will get kicked in the teeth by Linear Logic's shipping rates.

I believe Canadians can get a better deal from http://100mpg.ca/ (but compare before buying)

[KJSatz]

Originally Posted by whatjigg

Now what I am very interested in learning more about is this 'fuel efficiency mode' you mentioned and that i've seen here/there around forums. And as per my vehicle, yes the 08's were tweaked in Canada to meet the ecoauto gov't rebate program. For my car this meant some further engine tuning to do with gear ratio's i think and maybe some other minor changes, a lip spoiler (yes I agree, it's so small yet add's so much to the look of the car), and some undercar improvements to aid aerodynamics.

Really there are two facets to it, one of them dealing with iVTEC (under lowish loads from 1000-3500RPM the engine engages VTEC, using a less powerful more efficient cam on the engine), and the other this more complicated partial-charge-retraction thing which will occur in a subset of the times when VTEC would be engaged. Staying with the fuel efficiency cams is easy--light acceleration within that RPM range keeps it on--but the other part is hard to do consistently, and it's hard to see if you're in it. On a ScanGauge or the like (I do not have one, but I am looking to build an OBDuino when the ELM-free CAN version gets straightened out), monitoring the MAP sensor will tell you (it jumps down if you're in and jumps up if you're out).

I really envy all of the stock FE improvements your Civic got! I have an LX too, but it has worse gearing and worse aero off the line.

[MetroMPG]

The Canadian Civic LX has the same gearing as the US cars.

The tweaks used to qualify the cars for the rebate program are detailed here: http://ecomodder.com/forum/showthrea...tweak-274.html

[whatjigg]

Hey KJSatz, yes the extras were nice however, as envious you are of me, i am the same of you. When I bought it, the CDN $ was at par w/ USD and Honda was being a dink and saying that any car bought in USA and brought back would not have its warranty honoured (and not only that, they refused to lower prices given decreased value of USD and were just pocketing all the extra dough). At the end of the day, you paid a few thousands dollars less than I did even with my ecoauto gov't discount and negotiating down to $350cdn over dealer cost w/ paying cash.

Thank you for all the info & advice MetroMPG!! and I'd totally appreciate a lesson or two in hypermiling (maybe even when you get back).

As per buying the ScanGauge...have I considered it? absolutely, however... I've been driving with all these painfully slow/annoying even techniques for now three months. And on some tanks I really do accelerate as absolutely slow as possible, shut down engine while even coasting to lights that have turned red or down the really long straight hills, and yet I am NOT seeing the results. For all these painful procedures, I'm getting down 3-4% typically and sometimes less! In other words, when I go fill up my tank with 40L gas or whatever it may be at that time, i'm saving all of $1 lol. When I could be driving quickly, speeding regularly like everyone else in Ottawa, and accelerating fairly hard (although, normal driving for me typically doesn't involve me going over 3200rpm, even when i want to hit it hard, i only go to 4000-4500 max). On those tanks that i'm doing everything possible to get the mileage down, it's guaranteed that i must be in this so called 'lean burn mode' with the efficient cylinders or at least for quite a bit of the time. And even at that I get no significant gains.

This brings me back to the scangauage 2 - why buy it when I've driven whole tanks brutally slow with all the 'correct' (as i see fit) driving procedures? It's going to cost me $190 and will be a fun new toy and everything, but come on, I really doubt I'm going to see much better mileage (speaking from 3 months worth of pain in the ass driving techniques). If you honestly think this gidget's going to make a big difference, let me know and why?

Ford Man --> as per shifting any lower, that's not gonna fly, I mean this car has a redline of 6800rpm and 2400 is really about as low as you want to go, any lower and you probably can't be precise enough with the shift to get it bang on everytime and avoid lugging.