MAX: Our Quest for a DIY 100-MPG Car

Progress continues on MAX, the home-built, 100-mpg car (prospectively) that you’ll be able to make for $10,000.

| October/November 2009

Last year we introduced MAX, the MOTHER EARTH NEWS contender in the Auto X Prize fuel-efficient car competition (see Here Comes the 100-mpg Car). For those who may have just tuned in, the Progressive Insurance Automotive X Prize is a $10 million competition to create cars capable of achieving 100 miles per gallon in fuel economy. Entries must have a design that would allow for the production of 10,000 cars per year at the price most appealing to the manufacturer’s stockholders. We’re aiming for a more affordable approach: a DIY, fuel-efficient car that you can build for about $10,000.

Part of what I want to prove with MAX is that if I can build a 100-mpg car using off-the-shelf technology, the major automakers should be able to do the same, if not even better. Sure, MAX is different than a family sedan, but those car companies also have different resources than we do here in the Kinetic Vehicles garage. After MAX has been perfected — whether we hit 100 mpg or not — we will have plans available for those who want to build their own.

MAX is a sports car powered by a Kubota diesel engine that’s normally used in tractors. The car has turned heads and drawn crowds everywhere we’ve gone, and shown its heels to far zootier vehicles in everything from “play dates” on the twisty roads of southern Oregon to formal endurance racing from Berkeley, Calif., to Las Vegas (see MAX Wins 800-mile Road Rally, Without Gas).

You may be wondering whether MAX is practical. Well, we have more than 7,000 miles on its wheels now — everything from grocery getting to freeway flying — and it has served us reliably. For fuel, we’ve used everything from jet fuel to olive oil.

I bet I know your next question: Is MAX getting 100 mpg? Not yet. But so far we have the chassis and power source sorted out, so now we can improve MAX’s body, which will really improve its mpg.

Building a Better Body

The only thing holding us back from 100 mpg is air resistance. MAX’s current body looks cool and classic, but it’s an aerodynamic disaster. We’ll never see 100 mpg with this design. Frankly, it’s a bit amazing we’ve been nipping at 70 mpg (which we’ve achieved when cruising slowly). But we know what we need to do: Make a new body that has half the drag of the current one.

Jack McCornack
10/18/2009 9:09:55 PM

KeithOliver noted that... > ...anyone trying to copy the MAX concept is going to have to meet emissions regulations in effect at the time that they register. ...and that's true, but there are 50 different regs in 50 different states, and in most states homebuilt cars don't have to meet the same standards as high volume cars. > MAX was started a Loooong time ago... No it wasn't. MAX was conceved in '06, we started collecting parts and fitting things together in '07, and its registration date was '08, which is when MAX first hit the road. It's not registered as a heavily modified older car, it's registered as brand new in 2008. ...prior to soot filters and selective catalytic reduction being required... There are manufacturers working hard on those problems. Some of these manufacturers were quite interested in MAX as a demo platform before the final round of the Automotive X Prize rules were released, and affordable ceramic soot filters are just around the corner, and urea injection is coming out of the labs and hitting the roads already. It's not insurmountable. ...but that will no longer be the case in 2010 and beyond. One big thing MAX has in its favor is it doesn't make much exhaust per mile. I'm not sure how the other American auto manufacturers are doing it, but if they can pass EPA muster burning three times the fuel that MAX burns, our EPA-certified-for-agriculture engine might pass the auto emissions requirements, just the way it is.

Jack McCornack
10/18/2009 8:33:05 PM

Hi Bob, > I really feel let down that you are giving up the X-Prize contest. :-) You and me both, man. > The reason that you give that you would have to modify the engine to go from 20 seconds for 60 mmph to 18 seconds doesn't make sense to me. I know I've written a lot of words on the subject, but don't recall writing those. I'll acknowledge that the 0 to 60 performance issue was one of the first clues that the X Prize folks and I weren't seeing eye to eye, but it's not why we withdrew. I could write reams of details, but the basics are in MAX Update #32 in the MAX Update blogs. Improving 0 to 60 times by 10% isn't trivial, and I don't think the body change will do it. The streamlined body will add some weight, and it's possible the will hurt low speed acceleration as much as the streamlining helps it. We can meet their acceleration requirements with engine mods, but then we're getting out of our knowledge base re emissions, and I know the Kubota engineers worked hard to balance power against pollution. And of course, we could have got with the X Prize program and converted to electric, but then the budget would have skyrocketed, as would our carbon footprint. So we're keeping MAX a DIY car and paying more attention to economy (both fuel economy and construction/purchase price economy) than to performance.

10/17/2009 12:11:20 PM

Unless I'm mistaken, there is 1 big problem with the concept, and that is that anyone trying to copy the MAX concept is going to have to meet emissions regulations in effect at the time that they register. MAX was started a Loooong time ago, prior to soot filters and selective catalytic reduction being required, but that will no longer be the case in 2010 and beyond. I think the only chance the rest of us have is to retrofit an existing vehicle with a registration date prior to 2005. The earlier, the better, since the less stringent the emissions regulations. I have been looking and one cabn find Honda Insights with dead batteries for $1-2k. Good areodynamics come right out the box.

mother earth news fair 2018 schedule


Next: September 14-16, 2018
Seven Springs, PA

Whether you want to learn how to grow and raise your own food, build your own root cellar, or create a green dream home, come out and learn everything you need to know — and then some!


Subscribe Today - Pay Now & Save 64% Off the Cover Price

Money-Saving Tips in Every Issue!

Mother Earth NewsAt MOTHER EARTH NEWS, we are dedicated to conserving our planet's natural resources while helping you conserve your financial resources. You'll find tips for slashing heating bills, growing fresh, natural produce at home, and more. That's why we want you to save money and trees by subscribing through our earth-friendly automatic renewal savings plan. By paying with a credit card, you save an additional $5 and get 6 issues of MOTHER EARTH NEWS for only $12.95 (USA only).

You may also use the Bill Me option and pay $17.95 for 6 issues.

Canadian Subscribers - Click Here
International Subscribers - Click Here
Canadian subscriptions: 1 year (includes postage & GST).

Facebook Pinterest Instagram YouTube Twitter flipboard