Saturday, December 11, 2010
What a Summer It Was
Those of you who have followed the long and sometimes sad tale of the Karmann Eclectric may recall that the car finally hit the dragstrip in July at the Wayland Invitationals, and produced a promising 17.4 second, 74.8 mph run with several similar backups. Nothing to write home about, but not bad for a newby driver in a 40 year old car that's carrying 800 lbs of extra weight on skinny 165 mm tires and powered by a salvaged motor that was originally rated by it's manufacturer as 20 horsepower...
Eager to show this capability and more to the aircooled VW crowd at the Northwest's biggest annual VW show, I detailed the car and finally put some sticky rubber on the 6" wide Porsche phone dial rims that had been waiting patiently for a new lease on life ever since the poor 924 Turbo that they debuted on met an untimely end.. After washing the car, I carefully toweled a few drips off of the controller and let it sit in the sun for hours before driving it uneventfully into it's enclosed trailer for the trip south to Portland. The next moring, my venerable Godzilla 1800 amp controller, serial #003, which had reliably pushed the White Zombie past 100 mph so many times, refused to come out of it's cave. Thinking it must be a minor fault, I rolled it out and proceeded to spend the next four hours troubleshooting the car in increasing frustration before having to recruit passers-by to help push it back into the trailer, because of course, today would be the day for my Harbor Freight winch to crap out....
Turns out that some moisture had migrated under Grandpa Godzilla's skin, and it was more than his old heart could take. The power stage died quietly, rather than in spectacular fashion as they have been known to do. One photo mailed to the maker was all that would be required to seal his fate- dead, unrepairable, and to be consigned to the trophy case of John Wayland.
HowEVer, our story can't end there, because generosity knows no limits on the Plasma Boy racing team. Upon hearing the news, JW asked if I'd be able to come down a little early for the races, because he happened to have a spare controller that he would be happy to help me install and use, since the White Zombie was in good shape and pretty much ready to go. Yep, that's right-the man offered a brand-new, out of production Zilla 1K controller, unavailable at nearly any price, and at any rate, not warranted for racing use, with no strings attached.
After gathering my composure from the floor, I profusely thanked John, told my boss to forget about Friday, and spent Thursday night pulling out the rat's nest of precharge circuitry and relays that fed 'ol Godzilla, 'stubbing in" all the necessary wires to feed a hairball's much more sophisticated and safety-conscous control circuitry. I got two hours of sleep, and then headed for Portland. When I arrived, I found that John had already lined up a dream team of EV installers, led by Mark Farver and Aaron Choate of http://www.revoltev.com/ in Austin, TX and ably assisted by Brian Hughes of Seattle, who's fabrication experience in converting his own MR2 ( http://www.evalbum.com/1244 ) resulted in fine custom touches like a precisely-aligned adaptor plate that expanded the baby Zilla's footprint to fill the shoes that Grandpa left behind, complete with countersunk stainless machine screws. Roger Wright, John McGowen, and others who escape my sleep-deprived brain also made it all possible by contributing tools, supplies, and expert advice.. The install looks like something that was planned well in advance and shop-built, rather than assembled entirely with hand tools out on the street by a bunch of guys who had never met before.
After such a rushed install, I crossed my fingers and turned the key, and the Zilla immediately came to life. With just a couple of quick potbox adjustments and programming in some voltage and current limits, it was off to the races.
I was relieved to hit the track again and still high with a little help from my friends, but somewhat disappointed by the initial performance. I was once again running 74 mph in 17 seconds. Was it the smaller controller, or were my batteries not up to snuff? We limited battery amps to 800 to see how long they could put that out, and Ooer the next few runs, I got a bit more aggressive with the launch, improving reaction times and 60-foot times, but encountered the old enemy of a chattering clutch. It seemed that by going with wider, stickier tires, I had eliminated the extreme tire slippage and squeal from my first 60 feet, but the Kennedy stage III pressure plate and 4 puck ceramic clutch disc weren't hooking up. This papa knows that shaking any baby is bad, even a Zilla, so a few more runs were squandered with lighter launches, and I spent staging time on clutch break-in by slipping it at low rpms and putting in some heat, but hopefully not too much. Bingo! After break-in, the chatter went away, and I actually managed to spin the tires when shifting from second to third gear, which showed up on a DAQ graph as a devil's-horn shape in the amp curve. The graphs also showed that the batteries gave a full 800 amps as long as it was asked. Speed increased to the mid 76 mph range, and ET dropped to 16.48 seconds. Still far from my goal of 100 mph in 14 seconds, but any improvement is good, especially under the circumstances. Late on Saturday, I realized that though the motor amps were turned all the way up to 1000, I had forgotten to crank the battery amps over 800, which certainly robbed some significant performance... At least this time, there's sure to be a next time.
Thank you John Wayland, the Plasma Boy Crew, ReVolt EV and EVeryone else who helped!
Here's a little video of Mike Willmon's Crazy Horse Pinto making me look slow...
Posted by Jay Donnaway