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Moving toward a transportation system that fuels healthy people and a healthy planet.

MAX Update No. 66: Go With the Flo

Jan Steinman wrote this comment to MAX Update No. 65: Measuring Fuel by the Tablespoon:

MU66FloScan"If you're REALLY into precision measurement, look to the marine industry. Veggie Van Gogh uses a FloScan 9000. This device employs tiny turbines in the fuel line to accurately measure fuel use. It even has a NEMA interface to a GPS, so you can see your instantaneous fuel economy! That has changed the way I drive!”

Now I think Veggie Van Gogh is very cool. It's a snack van converted to a long distance camper/warehouse/workshop, it's powered by a four cylinder turbocharged Cummins diesel engine which has been converted to run waste vegetable oil. Jan and his accomplice Carol criss-cross the country, selling their wares at craft fairs, and they couldn't afford their gypsy lifestyle if they were buying and burning petrodiesel. Necessity is a mother, as the saying goes, and so Veggie Van Gogh was born.

However, even though I'm REALLY into precision measurement, I rolled my eyes at the suggestion that a FloScan fuel flow meter would be worth a hoot to MAX. Sure a gallons-per-hour meter that reads in tenths is useful for a van cruising 60 mph at 15 mpg; that's 4.0 gph (gallons per hour), and if the meter pops up to 4.1 gph or down to 3.9 gph, that's some useful information—it means their mileage has lost or gained about a third of a mile per gallon. Of course, there's some averaging going on, but accuracy within a third of a mile per gallon will teach you a lot about your driving style.

If we put the same fuel flow meter in MAX, which cruises at 55 mph at 85 mpg, it's going to read 0.6 gph most of the time. If it drops to 0.5, then woohoo! MAX is getting between 92 and 110 mpg. If the meter scootches up to 0.7, then bummer! MAX is getting between 69 and 79 mpg. All a 0.6 reading is going to tell me is, I'm not getting worse than 79 mpg or better than 92 mpg.

Accuracy within 13 miles per gallon isn't worth the trouble of installing the gauge, and that's not even considering the sticker shock (which I'll get to). I had greater precision with my Honey Bear fuel tank and an oven timer. So imagine my surprise when I learned that Craig Henderson has a FloScan in his 100+ mpg Avion, and he swears by it!

FloScan was developed for nautical use, but some models have a feature that makes them spectacular research tools for extreme high mileage cars like Avion and MAX: they have a GPS interface that lets them calculate mpg on the fly, and apparently (and contrary to how the gph display works) it gets more precise as economy improves. If it's showing 80.0 mpg and bumps up to 80.1 mpg, that's an awfully fine fact it's a bit finer than its repeatability (which is within 1/2%) but a half percent is good enough for me, and if it will tell me the difference between 80.0 and 80.5 mpg I'll be more than pleased.

Ooh I want one I want one. The only problem is, the latest FloScan with GPS interface sells for (gulp) fifteen hundred bucks. It's a bargain as a research tool, or for a relatively high dollar fuel sipper like the Avion (Craig is planning to offer the Avion as a kit), but it's a bit rich for MAX's budget. So if I do get a FloScan (and I am sooo tempted) it'll be part of my R&D toolkit, rather than a permanent feature of MAX's dashboard.

jack mccornack
2/3/2011 6:26:59 PM

Hi Rick, You are absolutely right and I apologize. I've been reconstructing, which means re-doing old stuff all over again, and even I find it boring. I want to get MAX back to where it was before I try my next round of improvements, since I didn't perform the quality and quantity of testing I wanted to do with the previous body (the white one)...but I may be being too much of a plodder. That's what draws me to the FloScan--it would give me instant fuel economy feedback instead of one data point per fill-up. Re a fuel efficient off-roader, that deserves some thought, and maybe even a prototype. Mother's Off Road Experiment, perhaps? We could call it MORE. Or a Mud-And-Dirt version of what we've got; we could call it MAD MAX. Unless that name's taken already.

rick pierce
2/3/2011 4:50:47 PM

Hi, Jack. I really look forward to new entries to your blog, but I must say that your entries seem to be farther apart and less 'meaty'. Obviously, the weather may not be the best, but aren't there any significant modifications (or even reconstruction details)) that can be mentioned? By the way, I would be interested in a variation of the Max that would be more off-road worthy. Some may say I'm a pessimist, but if the economy continues in the direction it's going, roads may not get the attention we have been used to and a more durable and less ground-hugging vehicle might be needed. (Think of your 'shortcut' on your trip east.) Your blog is still the first thing I look for when visiting Mother Earth News. Thanks.