Greetings from "Crazy Bill"
 

Hi guys,

Been reading your forums with great interest for several months, now. Have been interested in trying to get better gas mileage since a teenager in the early '70s. Used to harrass my parents, trying to get them to drive slower to see what kind of mileage we could get.

My first serious attempt to save gas by intentionally buying a vehicle for that purpose was my '82 Honda Nighthawk 450 motorcycle. I was hoping to get 60 on the highway, but was very pleased when it actually hit 70. Then when I had a clear plastic "plexifairing" installed (to keep me from freezing on long trips), I was surprised and thrilled that it started getting 75 mpg. My best tank ever on in was 76. But even so, I eventually decided it "wasn't worth it" & got rid of it.

Then, around 2004, after a short search, I bought a 1999 Suzuki Swift, 4 cylinder, 5 speed. I call it the "White Gnat" in honor of the Pink Panther's Inspector Clouseau's "Silver Hornet". I have exceeded 50 mpg on the highway in it a couple times, and even hit 51 once. It is "stock". However, it isn't running too well now & the mechanic says one cylinder's low on compression. .... so it may need a new engine.

But my "big project" now is the Yamaha 50 scooter I'm slated to get from my mother-in-law. Her late husband got it but only put 43 miles on it before he died. I hear they get 80 to 100 mpg "stock", and am considering the idea of lowering the seat and making a very steamlined "aero shell" for it. I'd love to be able to have lettering that says "Priuses are gas hogs" and be able to "back it up".

Bill

Maybe it's time for a Diesel swap into the Swift :D

Hmmm, interesting idea. Never really thought about that. Never really been a "diesel fan", but am aware they tend to get pretty awesome gas mileage. Wonder how much it would cost???

The cost can vary a lot, since there's a wide range of engines that can be used. From a 2cyl Kubota or a Kohler or the 3cyl one out of a Kawasaki Mule to a 2.0TDI, it's up to you.

OK, one of the reasons I finally signed up for this site today (er - YESTERDAY, now that it's 1am) is because it's the first time I used my new ScanGauge! I have another ScanGauge from a couple years ago in another car (my '99 Swift, or "White Gnat"), but it's on loan to someone else at the moment.

But after reading about doing a bunch of mpg tests on one tank with the ScanGauge (ABA, etc), I was intrigued. So I thought I'd try it on my 2000 GMC Jimmy 4.3 liter 4speed auto. One thing I'm wondering about is whether the ScanGauge is accurate for mpg BEFORE the 2nd fillup "calibration". Because this was immediately after the FIRST fillup (burning through that 3/4 tank so I can "calibrate"!! ;-)

The test I did, however, was very interesting, and the first time I'd ever seen such consistant results. Before, it was the "between fillups" tests, trying to drive a certain way with that whole tank, usually on longer trips, but usually with less than definitive results.

So what I did this time was an attempt to see if there was any clear difference for different speeds. I picked a section of freeway (and adjacent "old highway" for the slower stuff), and did 2-way averages, setting cruise control at "target speed", then hitting "current trip - reset" on the ScanGauge, then driving approx 5 miles on relatively level road, logging the mpg, turning around, resetting "cruise" and "trip", and going the same 5 miles in the opposite direction. This was in Washoe Valley (5200 ft. elevation) and around 64 degr and "light & variable winds". My results are as follows:

speed - n. bound - s. bound - avg. mpg
35 - - - 29.5 - - - 31.8 - - - 30.65
40 - - - 32.7 - - - 31.7 - - - 32.2
45 - - - 30.0 - - - 32.8 - - - 31.4
50 - - - 28.7 - - - 30.5 - - - 29.6
55 - - - 28.0 - - - 28.7** - - -28.35**
60 - - - 27.2** - - - 26.6 - - - 26.9**
65 - - - 25.5 - - - 25.5 - - - 25.5
70 - - - 25.0 - - - 24.7 - - - 24.85
75 - - - 23.0 - - - 24.4 - - - 23.7
80 - - - 21.8 - - - 22.5 - - - 22.15

** During both the 60 mph northbound run and the 65 mph southbound run, I came up behind cars that forced me to slow down for some period, probably interfering with the test's accuracy. However, the results still "looked reasonable" compared to ther rest of them.

As for the surprises; 1) I never dreamed I'd get over 20mpg at 80 mph!!! This is why I wonder if the gauge isn't accurate yet - I've had this vehicle for quite a few years now, and until today, thought I had a pretty good idea what kind of gas mileage it got. ???
2) I never dreamed 40 mph would be the "peak efficiency speed". I always thought it would be around 50, with the mpg dropping below that due to "inefficient engine speeds".
3) I never dreamed it would be such a clear-cut result. I've had some experience trying to do a series of repeated tests to determine a maximum something, and usually get frustrated because the results are usually "inconclusive". But if you plot out these numbers on a graph, the line is VERY definite (and much straighter than I would have expected).
4) That brings us to the surprise that it was so "straight"... I was expecting it to curve over sharply and to drop like a rock at 70 and above, but it didn't - just kept decreasing at about the same rate....
5) And I guess I was a bit surprised that there was a "point" at 40. Again, along with the sharp drop I was expecting at 70 and above, I was almost expecting it to flatten out and be about the same at 45, 50, and maybe even 55 or so. Nope, better and better to 40, then sharply down at 35.

I even repeated the round trip test at 40 mph to see if I could get a confirmation, or if that might have been a "flier". It was even BETTER!!!! (by a little bit). The second one was: northbound=31.9, southbound=32.9, average=32.4

A couple of details. My Jimmy is STOCK and a 4 wheel drive with around 150,000 miles on it. Windows up (closed), roof rack on, mirrors and radio antenna "deployed" normally. (gonna try it with the "mods" soon - AFTER ScanGauge "fillup calibration"). I already have the cardboard cut out for grille block & rear wheel skirts. Have one WalMart pizza pan for one front wheel, just need to pick up the second. AND I have couple pieces of plexiglass I need to bend in the oven for "aero" headlignt covers.

But who knew the ol' Jimmy would get 32 mpg at 40 mph?!?!?!? This is exciting! Of course, driving across Nevada at 40 mph might not be too exciting!!! HAH!!

An uncle of mine has a '99 Chevy Blazer with a 95hp 2.5L turbodiesel 4-banger bolted to a 5-speed Eaton and gets those 32 MPG on highway at 60 MPH. Inner-city is usually around 28 MPG. Anyway, I'm quite impressed you managed to get 32 MPG with the V6.

Oh, and I forgot to ask; has anyone else done this kind of test and got similar results? (or different results?) Any other "S-10" Blazers or Jimmys out there in the forum doing any kind of hypermiling/ecomodding? Just wondering.

Oh, and even though I'm an "SUV guy", I'm not trying to get super gas mileage at 80 mph, nor do I think driving "slow-ish" is particularly dangerous (well, I had some "white knuckles" during that 35 mph test when people were bearing down on me - - - ). But like our friend from Texas, I just love my SUV for certain things, and, considering what it is, still want to get the best mileage I can out of it....

Yeah, me too!! Although I have hit 31 in that car once before - on a trip from Carson City to Las Vegas - and I think I was going 45 to 50 mph most of the time that day, too - and hypermiling all I could - engine-off coasting, and even -gasp - running a stop sign here & there. I think I had the radio antenna off and the side mirrors folded back that trip too - and probably 50 psi in the tires....

OK, Cripple Rooster... I'm a "night owl", but you win - I'm going to bed!!

Most likely not.
Though the relative results will still remain after calibration.

The results from 35-45 seem to be in the same ballpark, though it could well be your car's most FE speed is 40.

At reasonable speeds though.
Depending on gearing, it may well be 20 mph ... at idle rpm in a high gear.


Road-testing for FE is tricky, as things change along the way - often beyond your control.
What we perceive as flat isn't always so flat either ;)
To do this really right, one'd have to measure the exact same stretch of road every time (from a milepost or a sign to another such landmark).

Site-starter MetroMPG has a thread on how to do road testing the right way - or as right as the road will allow you to test ;) - (http://ecomodder.com/forum/showthrea...ery-11445.html )

Personally, I don't do dedicated tests.
I do try out things on my regular commute.
If it works, it'll show on the gauges and ultimately show up in the fuel stats.

Welcome to the forum!

That lines up predictably with a broad range of other vehicles that members here and elsewhere have tested, as you did.

Generally passenger vehicles get the best cruising fuel economy at the lowest road speed after top gear is engaged. (Though sometimes at the lowest road speed in second from highest gear, for some vehicles with higher aerodynamic drag.)

FYI, see: http://ecomodder.com/forum/showthrea...you-15182.html

Glad you're having fun with the ScanGauge - I remember being pretty excited by the world of testing possibilities it opened up when I first got mine for my Pontiac Firefly (clone of your Suzuki, with the 1.0L 3-cylinder though).

That sometimes happens. Even though the aerodynamic load is going up dramatically as speed increases, depending on gearing and the engine in question, the engine may be be getting closer to its peak high-load efficiency zone - see Brake Specific Fuel Consumption (BSFC) Maps - EcoModder

Approaching peak BSFC as speed climbs would tend to "flatten out" the line on the chart. (Moreso than you would see with an electric vehicle, by comparison.)

Thanks euromodder,

I followed the link to MetroMPG's thread and read the entire thing on the proper way to do testing. Very enlightening. Obviously, my "single pass each way" wasn't very scientific, but I think I still gained some valuable information from it.

Regarding your caution about using the same section of road each time to a certain sign or milepost, I did that. Also, I did it both directions, so any deviation from "true level" should be compensated for, as well as any steady wind from any direction. And while the course was not level, and did, indeed have minor hills, I believe going both directions should have given me a pretty good average. And it was 5.3 miles (over 8 km) from one end to the other, so I think it was far enough to take out random little events.

Finally, my main purpose was to see if I could discern any difference in mpg with speed (boy, did I!), and furthermore, what seems to be the "best speed". So while I won't take the absolute mpg numbers as gospel, I think I now have a pretty good idea of how my car's gas mileage changes with speed.

Once I'm down to 1/4 tank, I'll do the "fillup calibration" on the ScanGauge, and go repeat parts of the test for comparison, probably just 40, 50, and 60 mph if there seems to be a good correlation to the first test. My "real" goal is to start testing my mods, rather than come up with exact mpg figures for different speeds in "stock" configuration.

Thanks,
Bill