MAX Update No. 26: Seeking Ideas for More Horsepower

http://www.motherearthnews.com/green-transportation/100-mpg-needs-more-horsepower.aspx

The rules for the Progressive Insurance Automotive X Prize have been under development for some years now, and all us entrants are on pins and needles — waiting for their release. We've had looks at rule proposals all along the way, given to us in confidence. That's really been the only challenge I've faced as a combination entrant/journalist: there have been times I've had burn-after-reading documents and had to resist my urge to blab.

But now that the latest draft of the Auto X Prize Competition Guidelines have been made available to the public, I'm going to ask for your advice.

The final rules are pretty certain to require we meet a performance standard of zero to 60 mph in under 18 seconds. Not much under, 17.999 will do, but for MAX, that's going to be tough.

What? 18 seconds to 60 mph isn't very fast, but you'd be surprised how many vehicles on the road can't do it. Fully loaded, my four-cylinder Dodge Caravan can't do it, and while it's hardly a performance car, it's adequate. Anyway, this 18 second thing is a fairly recent requirement. It wasn't in the projections when we signed up, so we had designed MAX from the get-go to hit 60 mph in 20 seconds.

Why 20 seconds? Because that's in keeping with the low budget sports cars you could buy new when I was young (and quicker than some, such as the Bugeye Sprites and the Karman Ghias) and I thought it could be done today with a 100-mpg, low-budget sports car. I'll confess we haven't hit 60 mph in 20 seconds yet. On paper it looks like streamlining will get us down to that, so I'm not worried. Or I wasn't before … but I am now.

To increase acceleration to a given speed by 10 percent (in this case, from 20 seconds to 18 seconds) requires more than 20 percent more horsepower. To skim over the math, it would take 10 percent more thrust applied for the same length of time, but by definition it has to be accomplished in 10 percent less time.

1.1 squared = 1.21 so that's 21 percent there. Plus there's no acceleration happening when I'm shifting gears and I doubt I can shift gears 10 percent faster (if it takes me a quarter second per shift then we're really comparing 17 seconds of acceleration with 19 seconds of acceleration). And we don't have much besides horsepower we can mess with.

Make MAX lighter? That'd be nice, but it's not likely to happen given the weight of the additional crash protection structure we're installing.

So to put it simply, this upcoming performance rule is going to call for about 25 percent more horsepower than we have now. How are we going to go from the 32 horses we have to the 40 horses we need?

Beats me! But we're sure not giving up; we're going to find out. The first step of our research is to ask you. Got any ideas on how we can boost our power by 25 percent without hurting fuel economy? If so, please post a comment below!


Browse previous MAX Updates.
Read the introductory MAX article, Here Comes the 100-mpg Car.
Visit the Kinetic Vehicles website for more technical details on MAX.