Broke the 50mpg barrier at the MPG Rally!
 

First the facts and numbers:

'07 Honda Civic EX, 91 miles, 1.711 gals.

53.19mpg!

Now the long story: The odometer read 86 miles, but the official distance of the MPG Rally in Lacey, WA was 91 miles. Either way, even when figuring the distance at 86 miles, this equals 50.26mpg. My primary goal was to reach 47.1 mpg, which would be just under 5L/100km - a nice goal. 50mpg was what I was hoping for, but wasn't too sure if it was even possible with a mainly stock car.

But one can try, right? :D

Removed all non-essential items from the car: spare tire and associated tools, rubber trunk tray, rear headrests (three in this car), maps and window cleaning kit, CDs, center console doohickeys (audio adapters, hand sanitizer, pocket knife, etc). All in all it filled a wheelbarrow, but probably not more than 50 lbs in weight.

Made sure tires were at max sidewall pressure: 44psi. Checked the upper grille block. Drove with wife, aka co-pilot, to breakfast place some distance away to warm up engine and fluids thoroughly. Filled up at gas station which traditionally has provided good fuel for me with 92 grade.

Short of serious surgery on the car more could not be done.

This was my first serious effort at pulse and glide. We were barely averaging 36 mph in a stretch that should average 50 mph. It was raining and we had to crack the windows to prevent fogging and A/C use. All in all mentally very draining, but the result speaks for itself.

This trip will go in my gas log probably as the all-time high, because the effort to reach that over long distances would simply be overkill. But theoretically, with topping the tank off to the brim 700 miles would be possible. That is equivalent to driving from Olympia, WA to Sacramento, CA on one tank.

Thats pretty good. I can get into the mid 50's, but my avg speed is down below 30mph.

20-40mph EOC gets me the best mileage that technique can get out of the car.

So what do you get if you cruise control at, lets say, 55mph? (just wondering)

Depends on the temperatures outside - but from 36-38 mpg (winter) to 42-44 (summer, no a/c). FYI, this is a manual I'm driving, which is at 2600 revs when going 60. The automatic revs lower (2200 or so) at the same speed, but I think it's eager to downshift too.

Sweet! You gotta love Hondas! What kind of roads were you driving on? Back roads? I take it was not very busy if you were getting away with doing 36mph.

We first headed south out of town, 35-40mph speed limit. Traffic was not overly busy. Then 50 mph limit for 70% of the route with a few towns thrown in where 30mph was max. Of those 70% about 30% were on narrower winding backroads. The last section was through town 25-30 mph.

We were holding up traffic so badly at one point that P&G became unsafe. Drivers following were too aggressive. I decided to stop for a few minutes and let the line of cars following - about 10 of them - pass. Not that there was a solid line between lanes, no... my wife says that passing on two-lane roads isn't taught in driver's ed - is that correct? It was mandatory in my course in Austria - where passing isn't necessarily a sign of impatience like in my area... Oh - have I let this response turn into a rant? :p

Haha, congrats on the good mileage superchow! A few good aeromods will definitely see you breaking 40 on a regular basis.

Very nice! I grew up in Federal Way. Traffic is so much heavier now than it used to be. Even in the outlying areas like Lacey.
I have no clue about what is taught in driver's ed. That was 30 years ago for me.
Congrats on your performance!

Do you happen to know what LOD you were throwing during your pulse? And you EOC in between pulses? What were your max/min speeds for the p&g? What gear did you use?

Sorry I have pretty much the same car (08 LX sedan MT) so I'm curious. I've always wanted to get a tank over 50....

That's OK, happy to share information. I don't have a ScanGauge, so figuring LOD (= Engine Load?) is more guestimation. But basically I tried to stay under 25% throttle when pulsing - just gentle gradual acceleration. I pulsed to about 55 mph and glided back down to about 25-35 mph. We figured we had to do that because of the time limitation. That way we could bump start the engine in 5th smoothly. Yes, turned off the engine for the glides.

Because the accelerator pedal isn't directly linked to the throttle body, but rather is interpreted by the computer, having high loads at low engine speeds actually hurts the mileage. At low load and low revs the i-VTEC kicks in and switches to lean burn mode and opens up the throttle plate for reduced pumping losses - or so the Honda documents say I've found searching the interwebs. The engine is most economical between 1500 and 3500 rpms according to those sources.

I found that the best trick when driving my car is to avoid varying the throttle pedal too much - when cruising keep the gas pedal in one position. Even if the revs climb the engine should stay in lean burn mode up until about 3500 rpm, or 80 mph, if there isn't too much cross- or headwind. This is speculation, and I unfortunately don't have the money to verify it with a ScanGauge. But so far the above information has yielded the best mileages.

What do you do to stay over 40 mpg? My driving is plagued with lots of city driving...

Did you use 5th all the way from "25-35" to 55, or what combination of gears did you use?

As for staying over 40mpg, most of my driving is highway. I have done a couple hundred miles of city driving this tank, and it seems like I've been having success according to the scangauge (which I have not adjusted...).

If the speed was down below 35, then I'd bump start in 5th, shift into 4th and accelerate back above 35. Then back to 5th gear all the way to 55.

Here's a graph I found on Temple of VTEC Asia in the i-VTEC implementation on the K20A engine. Yes, it has a DOHC vs SOHC layout, and 2.0 liters vs 1.8 in our cars, but I believe the general implementation of the different "phases" are similar. (The torque graph is uncannily similar...)

http://asia.vtec.net/article/k20a/11_06.gif

Here the link to the whole article: Honda's K20A Engine

Most interesting to me was the probable fact that low revs/high load (zone "3" on the graph) in this car is counterproductive. I'm estimating the switchover from "Low cam" to "High-speed cam" at about 3500 rpm. So, in conclusion: Loads from 15-20% to 50-55% and revs from 1500-2000 rpm to 3000 rpm should keep the engine in the "lean-burn" range, zone "1". (Idling will also keep the engine in lean burn, which may be worth an experiment in the future comparing different driving methods.)

Well I am not completely sure about this information. Our engine, R18, does not have lean burn. It's pretty difficult to get meaningful acceleration at LOD 50%. I'll do some experiments trying LOD around 60 and see if it works alright.