2008-05-08	423.3	8.85		47.83	"The first tank using hypermiling techniques. I had also installed some front wheel deflectors like those seen on almost all newer cars. The fill was probably quite off; I have never seen this result since with a mix of city and highway driving, and all I really did was go slower and coast to stop. All tanks until 8/10/08, unless otherwise indicated, are about evenly split between city and HWY driving, with the city cycle usually in areas of dense traffic and traffic lights, and the HWY cycle usually in low traffic. NB: All entries show distance traveled as 1.02505 times the odometer reading in order to compensate for larger rolling diameter of 195/60-R14 tires versus stock size of 175/70-R13."
2008-05-20	391.6	9.812		39.91	"Inflated tires from 33 to 38 PSI."
2008-05-29	360.8	8.459		42.65	""
2008-06-08	258.5	4.444		58.17	"95% FWY @ 65MPH w/ 2 passengers. The fill was probably a little off, giving a better MPG than the same trip has yielded many times since."
2008-06-09	412	9.721		42.38	""
2008-06-21	408	9.675		42.17	""
2008-07-04	422.3	9.526		44.33	""
2008-07-18	416.2	9.188		45.3	""
2008-07-25	416.2	9.861		42.21	""
2008-08-04	211.1	4.315		48.92	"Last tank with the driving conditions described in the first log entry."
2008-08-09	239.9	3.629		66.11	"97% FWY @ 60-65MPH, using some drafting behind semis. I think the fill was also somewhat low."
2008-08-10	124.1	2.5		49.64	"95% FWY @ 65MPH"
2008-08-27	132.3	3.542		37.35	"90% FWY @ 75MPH w/ 1 passenger and 125lbs cargo."
2008-08-28	345.4	6.982		49.47	""
2008-09-10	244.9	6.001		40.81	"95% FWY @ 65MPH w/ 1 passenger and 50lbs cargo. No explanation for the low figure except low previous fill-up (but it would have to be very low to bring this figure up to the norm)."
2008-09-11	214.3	5.086		42.14	""
2008-09-24	271.6	6.058		44.83	"95% FWY @ 75-80MPH w/ 1 passenger and 175 lbs cargo. There were also 2 blasts up to 100MPH (don't ask)."
2008-09-25	382.3	9.81		38.97	""
2008-10-09	257.1	6.56		39.19	""
2008-10-22	436.7	9.231		47.31	"1/2 tank was HWY trip @ 65MPH. Tires inflated to 39PSI."
2008-11-03	360.8	9.323		38.7	"New daily commute started: 10mi each way, 1/2 FWY, rush hour, hills, lots of lights. Also, colder weather and probably winter gas began."
2008-11-22	355.7	9.226		38.55	""
2008-12-10	381.3	9.498		40.15	"Mostly city miles, very cold weather. Installed 1/2 grill block and front tire deflectors."
2008-12-29	363.9	9.625		37.81	""
2009-01-13	246	6.992		35.18	"95% HWY @ 70MPH w/ 1 passenger."
2009-01-15	364.9	9.24		39.49	"Mostly city miles, some snow, very cold weather, very heavy traffic."
2009-01-31	363.9	9.24		39.38	"New commute (12mi in city w/ 1 passenger during rush hour) and freezing temps in winter have knocked avg. to high-30MPG. Goal: 40MPG city, 60MPG @ 65MPH hwy, 50MPG combined"
2009-02-13	341.6	8.999		37.96	"Generally very poor traffic conditions through this tank, along with cold temps."
2009-02-21	172.2	5.211		33.05	"Tried city P&G this tank with horrible results. Almost positive I wasn't getting into open loop, so this is mysterious. I probably accelerated too much in traffic, forcing me to brake before getting a good coast, but this alone would not explain the horrible mileage. WAI appears not to have helped. It is possible the ECU was retarding timing and/or enriching the mixture to prevent detonation with such high load at low revs."
2009-02-22	105.6	2.088		50.57	"This was a FWY test loop to get a pre-undertray baseline for HWY MPG @ 65MPH. No traffic interference, moderate temp (50°F). Pretty pleased with the result."
2009-02-28	181.9	4.716		38.57	"No P&G this time, and removed WAI. Also reset ECU."
2009-02-28	102.7	2.076		49.47	"This was a FWY test loop to see if the front undertray improved HWY MPG @ 65MPH from the baseline run. Similar conditions, though there may have been more wind and at a worse angle. Unfortunately no improvement observed."
2009-03-17	403.9	10.01		40.35	"First tank with front coroplast undertray. Also used P&G below 45MPH, but with a lighter pulse (25-40%) as opposed to the previous P&G attempt with pulses at 50–80% throttle. Almost all city driving this tank, so the slight improvement over average tanks should be attributed mostly to P&G, not the undertray. Just can't seem to break 40MPG with this commute! Perhaps when the weather gets warm and summer gas comes this will improve."
2009-04-02	405.9	10.17		39.91	"Almost all city miles. Same moderate pulse technique as before, with perhaps about 10% more throttle in pulse. I got a little less focused in the last 100 miles or so; not anticipating quite as early, not being willing to coast down as much w/ traffic behind me. I also had a few short and/or heavy traffic outings. Based on next tank's higher than likely MPG, I estimate the fill-up here was probably at least .318 GAL over, giving an adjusted figure of 40.19 MPG for this stint. Looks like I have probably cracked 40 MPG for the commute!"
2009-04-08	159.1	3.766		42.25	"Mostly city commuting, but a couple brief hwy runs, and a couple of bumper-to-bumper and other very low-efficiency situations. I am fairly certain the MPG figure here is too high. Based on previous experience with a mix of conditions like this, I would say the true MPG is no more than 38, meaning this fill was .318 GAL over the last. Because I don't have control over fill-ups (Oregon doesn't let you pump your own gas), stringing together multiple fill-ups under similar conditions is more accurate. So, for this and the 2 previous tanks, my commuting fuel efficiency is 39.47 MPG. I am getting close to my goal of 40 MPG city, but not quite, as my commute is about 25% HWY."
2009-04-09	252.3	4.869		51.82	"224 MI FWY loop @ 65 MPH, so 91% FWY miles this tank. Attendant topped off .35 GAL, so this probably .1-2 GAL over compared to last fill, giving a revised figure of 51.58-52.68 MPG. Factoring out the 11% city MI, est. at 39 MPG, gives an estimated 54.58-55.94 MPG @ 65 MPH (53.28 not considering fill-up issue). Other factors to consider: very rough pavement, 1st FWY stint was into moderate crosswind, several large hills on FWY circuit. This is a step above the 2 previous FWY loop tests in no better (and perhaps worse) conditions, suggesting that the combination of front side fairings and front tire aero deflectors is measurably effective."
2009-04-24	395.7	9.09		43.53	"Mostly city commuting, but a couple brief hwy runs. This is about 3 MPG higher than normal, so either I have improved my P&G technique and/or traffic anticipation, or summer gas has arrived, or the warmer weather has helped. If the next tank is normal, this is a great result."
2009-05-06	271	7.396		36.64	"Almost all city commuting this cycle, but terrible FE. Nothing really different in comparison to the last tank, however, which suggests a low fill-up last time. If I average this and the previous tank, it comes out to 39.45 MPG, right at my city commuting average, so I will chalk this low figure up to fill-up discrepancy."
2009-05-06	236.3	4.364		54.15	"FWY loop @ 65 MPH w/ only about 5 MI in city and 2 cold starts. In one direction there was fairly heavy rain with strong wind coming at me at about 45 to the left, and in the other direction there was no rain and the wind was reversed but still strong. I would have thought these conditions would have dropped the MPG by a couple points from last time even though I noted wind on that trip as well, because this was worse, but instead I got a 4.5% improvement over that trip. This suggests that the small aero mods I did for this trip measurably improved my HWY FE: extended front tire deflectors inward to divert the airflow around the wheel well openings, and added very simple, small rear tire deflectors."
2009-05-19	353	9.554		36.95	"This tank I decided to drive without paying attention to fuel economy in order to measure how much my hypermiling techniques are improving FE. I didn't EOC, didn't try to maximize coasting (although there are some longer sections on my commute I bet most people are coasting through anyway), drove faster, and accelerated harder and at higher RPMs. I'm quite surprised actually, to have done so well, though this is only a little better than I used to get over a year ago before I started hypermiling. Also, I probably did about 10-15% more highway miles than normal. But still, it's rather discouraging to see that all my effort is worth so little! The best/worst case scenario would be that this was up to 1/4 GAL underfilled, which would bring it down to a little over 35 MPG. Perhaps the fill-up before was the first with summer gas? Perhaps slightly warmer weather also helped a bit?"
2009-05-26	209.3	4.578		45.72	"Normal commuting miles. Returned to normal hypermiling techniques, but tried to improve coasting distances (by reading traffic better), shifting at lower RPMs, and finding more opportunities to EOC. I won't credit the substantial improvement to my techniques, however; I'm pretty sure this was the 1st tank of summer gas since the previous tanks didn't show any sudden jump."
2009-06-20	407.7	9.751		41.81	"Normal commuting miles. A friend had borrowed the car during the previous tank so I did not calculate that. He filled it up and drove 8 miles before returning it to me."
2009-07-01	225.9	4.802		47.04	"Mostly normal commuting miles, with a few extra city trips and short hwy stints. Some miles in very bad traffic/lots of short busy street blocks. Since this was about a half tank's distance, any before/after fill-up difference will be magnified. The average of this and the last tank comes to 42.47. Not bad."
2009-07-02	260.4	5.437		47.89	"FWY loop @ 65 MPH w/ about 25 MI in city and 4-5 cold starts. Assuming 44 MPG for the city miles gives a FWY-only figure of 47.05 MPG, which is very disappointing. The weather was fairly hot, there seemed to be little wind, and there was very little traffic. My buddy had the passenger window down about 2 inches most of the time, which may have taken the MPG down by 1 or 2. I had also recently performed basic maintainance: spark plugs and wires, distributor cap and rotor (which showed significant corrosion), and valve adjustment; and also added a rear undertray/diffusor and radiator ducting. Since the last tank's FE was so high, I am assuming that a lot of the reason for the low figure here is that I was short-filled on this tank."
2009-07-16	397.7	8.554		46.49	"Mostly normal commuting miles, with a small percentage of extra HWY miles. Added rear undertray/diffuser and radiator ducting. Warm to hot weather."
2009-07-30	460.6	9.115		50.53	"Almost all normal commuting miles. My normal commute now is 20.5 MI round trip, with 9.0 MI on the FWY (which frequently backs up in a couple places). During this tank I avoided the worst of rush hour more than usual by leaving for/from work earlier, yet there were several times, including some non-commuting miles, where I was in bad traffic. One day I drove about 40 MI and didn't worry about FE, and in one instance, due to frustration and an open road, I went from 0–85 at full acceleration. The weather was also quite hot for this tank, including a week where it stayed between 90 and 105 F (this was a very good test of whether my undertray and radiator block/ducting have compromised cooling--it would appear not, since I had no overheating or constant cooling fan operation), which meant that several times I was at 50 MPH or above with the windows fully open. All that said, the MPG for this tank is quite impressive, and I can't really account for it, as I was not even the most vigilant I've been about hypermiling techniques. I do expect the next tank to be less impressive than this, perhaps so that between the two the average will be about 45 MPG."
2009-08-14	425.2	9.332		45.56	"I think this was all fairly normal, but I don't have notes for it."
2009-09-01	468	8.985		52.09	"Mostly normal commuting; some in-town highway trips, some bumper-to-bumper traffic situations, so it should average to about normal conditions. This is exceptionally high, especially considering the last 1/3 of the tank I wasn't EOCing and shutting it off at long lights because it was having trouble restarting in both situations, possibly due to dirty gas. I think the fill was at least 1/2 GAL short, but I will have to wait and see at next fill-up."
2009-09-18	409.2	9.407		43.5	"Mostly normal in-town miles, but traffic seemed significantly heavier in daily commuting. Suspicion of low fill on previous tank confirmed by the low figure here."
2009-10-05	441.8	9.248		47.77	"Almost all normal commuting miles. Conditions are getting worse: Traffic was on average quite heavy, especially on city streets. The weather has dropped 15-20 degrees in the morning and evening, and this makes my car cold-idle much higher and take 2x as long to come to normal temp. There is one particularly inefficient stretch about a mile long on the return home from work: 7 lights, usually stopping at 4 or 5 of them, and the slowest part is 1/4 mile long uphill. Now I'm just waiting for the FE hit that winterized gas will soon give."
2009-10-19	416.1	9.223		45.12	"Normal commuting miles except for about 60mi hwy at night in the rain. Traffic was slightly better the last half tank. Temps are about 15 degrees colder in the morning and evening, meaning the idle is up and it takes longer to reach normal engine temp. Also, I've stopped EOC because of problems with it not starting up right way, and this could have quite an impact."
2009-11-05	383.4	9.873		38.83	"Ughh, winter gas and cold weather. Normal commuting miles, more short trips and perhaps less HWY miles than usual. Consistently bad traffic. I need to check the ignition timing. I wish I had a block heater! On the way to work I've usually driven 3+ miles in slinky traffic before I ready full temp, and on the way home I've got 1.5 miles of extreme congestion with 5 lights before the FWY, and then 1/2 mile uphill in congestion on the tail end. I still don't feel comfortable EOCing right now due to the occasional failed restart in the middle of traffic."
2009-12-02	411.4	10.23		40.22	"Normal commuting miles, some extra short trips, and about 100 extra HWY miles. The weather was another step colder for this tank, and traffic is consistently worse at all hours and directions than it was in the summer. Nonetheless, the reduction in FE for this and the last tank can be completely attributed to lengthened warm-up and winter fuel formula. The first factor could be reduces using EOC, but restart is too unreliable with my car for this to be a safe practice. Toward the end of this tank I finished the full undertray and added front and rear wheel deflectors, and perhaps on the HWY that will show FE gains."
2009-12-09	154.5	3.936		39.25	"Normal commuting miles. Extremely cold weather (sub-freezing) and very bad traffic. Takes 4 city miles (est. 8 minutes) to reach normal operating temp. Tire pressure was at 34, which was hurting coast distances. I will get 40 MPG commuting eventually."
2009-12-16	412.7	9.145		45.13	"240 HWY miles (@65MPH) plus normal commuting miles. Very cold weather, heavy traffic. First full tank with full undertray and tire deflectors. I was expecting better. I also suspect a slightly low fill-up, which should show up in a particularly low figure next log entry."
2010-01-04	392.6	8.978		43.73	"Almost all commuting miles, using new street-only route. It's a slightly longer distance and takes longer to complete (unless traffic on the other route is very bad), but it has more predictable stops and a lighter traffic flow, and more opportunities for P&G. If I could EOC it would be quite the route, but my car doesn't restart reliably enough. The result here is good, but I will need 2 more fill-ups using this route to confirm that it is better."
2010-01-18	361.8	9.458		38.25	"Almost all normal commuting miles using new street-only route. A disappointing drop from last tank, but the 2 combined suggest this route is resulting in perhaps a 2 MPG improvement. This is significant, especially considering that the route change is only on the return trip, so that it accounts for only half the total commuting miles. Temperatures have risen a little on average from a couple weeks ago, but this appears to have made little difference in FE. This is corroborated by the fact that warm-up seems to take nearly the same time/distance as before in cold weather. I have added more rubber strips to the edges of the hood to seal the engine bay in more. Also, I covered up several inches of open area in the undertray running directly under the exhaust in the engine bay. Both changes may negligibly improve warm-up through engine bay heat retention."
2010-01-26	253.7	5.554		45.68	"About half commuting and half in-town and HWY miles. Colder weather this tank, especially in the morning and evening, when virtually all of my cold starts are. Great result, though I have no explanation for it except perhaps that the HWY miles improved the average more than I would expect. It does look like I've finally cracked a 40 MPG average for commuting this winter, due to either othe change in return route or improvement in driving technique, or both."
2010-01-27	242	5.095		47.5	"All HWY miles @ 65 MPH, except for 10 city miles. Also, 10 minutes of stop-and-go traffic on the HWY. 1 225-LB passenger and 25 LBS cargo. Result is lower than expected by a few MPG. This was the 1st tank with revised front tire deflectors and rear suspension covers, so it's a good test of aero. I seemed to lose less speed on some of the segments on this route where I coast. Unfortunately I don't have enough data to confidently say whether or not this is any kind of improvement in HWY FE."
2010-02-11	385.9	9.125		42.29	"Overall a very normal tank--mostly commuting, some extra HWY miles and extra short city trips. I am definitely averaging slightly above what I was last winter, which I'm happy about. I'm not as gun-ho about certain things now, like parking lots and always coasting to the lowest speed possible."
2010-02-21	361.5	8.529		42.38	"Normal commuting miles except 40MI extra HWY and 20MI doing coast-down tests (accelerating quickly up to 70MPH and coasting down to 40MPH. Colder weather during the last week."
2010-03-06	388.1	9.431		41.15	"Mostly normal commuting miles, but more extra short-trip, congested city miles than normal, and worse traffic than normal. Also, front undertray is being revised, so aero is probably slightly affected HWY FE."
2010-03-20	406.3	9.399		43.23	"Average driving conditions. Somewhat warmer weather. 1st tank after running Seafoam through the previous tank, but still need to run it through the intake manifold. I actually tried shifting at 2 MPH higher this tank as an experiment, because at where I was shifting before the engine did nothing no matter what load I gave it. At just a little bit higher RPM on upshifts the engine responds to wider throttle much sooner, hopefully meaning that I'm running closer to the ideal BSFC load more often. It perhaps works, and it certainly doesn't seem to hurt, based on the FE here."
2010-04-03	391.2	10.18		38.43	"Average driving conditions, somewhat warmer weather, new front lip and radiator duct, incomplete new front undertray. Mostly commuting, but considerable extra city and HWY miles, many shorter trips in which engine did not reach full temp. Also, fill-up after this tank was definitely topped, as gauge is unusually at current trip mileage."
2010-04-19	445.4	9.129		48.79	"Great result, probably mostly from high previous fill-up. Fairly normal mileage profile, but less driving with a passenger."
2010-05-10	409.5	9.077		45.11	"Fairly normal driving, except w/o passenger for most of commuting. Possibly more HWY or off-rush-hour miles. Good result, possibly due to Seafoaming the intake, doing a timing adjustment, and this being the first tank of Summer gas (but I don't know if the latter is true)."
2010-05-28	404.4	9.487		42.63	"Almost all commuting and city miles. Some route experimentation."
2010-06-19	380.3	8.1		46.95	"Normal commuting and in-town miles. This looks like a decent result but the fuel gauge needle was on empty and I've never had a fill-up of only 8 gallons before. I would have expected it to be at least 9.5 gallons, and I suspect the attendant short filled me. Supposing that I did actually use 9.5 gallons over this mileage yields 39 MPG, which is low but realistic considering I that wasn't trying very hard and I tested some new commuting routes that proved inefficient. As a compromise, I will estimate the true fuel use over this mileage to be 9.25 gallons, yielding 41.1 MPG."
2010-06-20	277.4	6.984		39.72	"90% HWY miles at 65 MPH. First time I have been able to use the vacuum gauge for constant HWY driving, so I'm just learning. Half of the HWY miles were with 2 passengers and 50 extra LBS of cargo, and that was going out of town, which has a long climb at the beginning. I still had 1 passenger on the return trip. Also, for much of the in-town miles I had the same 2 passengers. For one 4-mile trip with lots of lights, I had 3 passengers who probably totaled 675 LBS. This result is very disappointing, but is due in part to the previous short fill. Subtracting the difference between the previous fill amount and my estimate of true fuel usage from this fill yields 47.55 MPG, which is still disappointing. This could suggest that my latest aero mods (front lip, revised front and rear deflectors, exhaust tunnel vents, and roofline extension) have actually increased drag, but speed loss from coasting on downhill HWY sections seems to have been reduced slightly from what I remember."
2010-07-14	356.9	6.776		52.67	"Normal in-town miles, largely commuting but also more extra trips with short HWY segments. Amazing result, but probably at least partially due to discrepancies in this fill-up (done by me) and the previous 2 (done by attendants). No passengers."
2010-07-18	286.9	5.755		49.85	"220 MI @ 68/63 MPH on a 110-MI segment in both directions. The rest were city MI, half with cold starts. No passengers or heavy cargo."
2010-07-25	355	6.936		51.18	"225 HWY MI @ 65 MPH, in both directions on mostly the same segment, with no cold start in between. Also, about 50 HWY MI besides, with cold starts. The rest were city MI. No passengers, and some negligible cargo."
2010-08-09	445.1	9.097		48.93	"Commuting plus 220 HWY MI @ ~68 MPH ( in one stretch). No passengers, 300-350 LBS cargo for 110 MI. Hot weather; possible occasional pinging at very low RPM & high load. Need to provide intake with more air from outside front- and top-sealed engine bay. Strakes installed on undertray inside of front wheel wells and behind front wheels. HWY stability improved, esp. over 65 MPH; front feels planted and steering feels heavier."
2010-08-09	230.9	4.366		52.89	"All HWY MI @ ~72 MPH (in one stretch). Possible short-ish fill. No passengers, 40 LBS cargo."
2010-08-26	622.5	14.12		44.09	"Combined 2 fill-ups, the 1st only 3.375 GAL, the 2nd 10.747, which is most it's ever taken at once. 1 HWY trip of ~230 MI @ 65 MPH with no passengers or cargo. Other miles in-town, mostly commuting, but generally a wide range of driving conditions. Aero performance perhaps slightly reduced due to 1 exhaust tunnel gill falling off and some disintegrating strakes inboard of the wheel wells."
2010-09-05	492.2	9.72		50.64	""
2010-09-24	444.1	8.902		49.89	"I don't remember enough about the driving I did on this and the previous tanks. It included a decent amount of HWY and rural roads, but also commuting. No aero mods changed."
2010-10-06	344.1	8.043		42.78	""
2010-10-18	480.3	9.39		51.15	"Lots of variation, including a drive to the coast and back at high speed. Weather is colder now, especially in the morning and evening when I usually cold start."
2010-11-04	422.8	9.348		45.23	"Normal commuting and in-town miles. Cold weather in mornings and evenings, when I usually cold start. Start of winter gas."
2010-11-24	398.9	9.348		42.67	"Almost all normal commuting miles during rush hour. Frequent cold and very wet weather, including some freezing temps. Definitely winter gas formulation—somewhat noticeably slower acceleration in optimal manifold pressure range."
2010-12-08	320.8	8.195		39.15	"Normal commuting and other in-town miles. Very cold weather. Frequent slow city driving."
2010-12-09	241.7	4.484		53.9	"To Eugene and back, 1 passenger and heavy traffic (stop and go to 30 MPH for 10 MI) out of town on the way there @ 65 MPH, but no passenger and light traffic on the way back @ 60 MPH. Frequent bouts of rain with lots of standing water, which noticeably hindered coasting downhill. Excellent HWY mileage for this time of year, but I would attribute some of it to up to .25 GAL discrepancy between this and the last fill."
2010-12-22	386	9.65		40	"Last fill-up. The Daq Civic is DEAD!"