It’s often said (you’ll certainly see it a lot here) that electric motors produce monstrous torque in comparison to their overall horsepower. It’s the force that causes your circular saw to accelerate with a slam, achieving 75% of its maximum RPM in a quarter second, and achieving full speed in the next 2-3 seconds. Scale that phenomemon up to a full-size car with a controller capable of feeding the necessary amps, and you’ve got a formula for some pretty exciting off-the-line acceleration.

But how much is a “lot” of torque?

Just to put things in perspective, check out this article about the new Bugatti Veyron, which is now the fastest road car in the world. At 1000 BHP, it soundly beats — no, humiliates — the performance of the previous record-holder, the McLaren F1. (My favorite oft-reported statistic: if the Veyron launches from a standstill as an F1 passes it at 120mph, the Veyron will beat the F1 to 200mph.)

The point I wanted to make here isn’t about power though; it’s about torque. Read to the end of the page at the above link — the torque that this massive quad-turbo W-16 engine produces is far and away the most ever seen from a road car, at 922 ft-lbs. That torque is directly related to the feel of acceleration you will experience from the car, and the number is truly unprecedented … from a road-going gas engine.

There is not yet any detailed information about maximum horsepower or torque available from the motor I’ve chosen, but with the earlier (shorter) prototype, I have dyno data indicating just a hair under 900 ft-lbs, at 1400 amps. With the longer armature section (i.e. more torque per amp), I expect the figure to be competitive with the Veyron.

And then of course, there’s that issue with amps — see, I won’t be limited to 1400A, as the guys at the motor shop were. My controller will be capable of 2000A on the motor side, and with a controller bypass perhaps 2500A or so is achievable at WOT. This puts torque output well past the most powerful road car ever built.

Reality check - notice I didn’t say power output. The ability to maintain a certain torque at a given RPM or vehicle speed is dependent on power. And there’s really no comparison with 1000BHP, at least not for $35k from my garage. Lest we conclude I’m having delusions of grandeur quoting my singular comparable statistic with such a product of engineering greatness, let’s enumerate some of the ways in which my project will NOT produce even a cheap electric mockery of a supercar:

• AWD. My truck will power the rear wheels; true supercars like the Veyron and the F1 send power to all four.
• Tires. I won’t have 14″ wide super-gummy tires in back, at least not on the street. In fact traction on the street is looking like it’s going to be a big problem, unless I detune the controller (which is probably a good idea anyway).
• Gearing. Unlike a real supercar, I won’t have a transmission, at least not at first. So, my motor’s torque won’t benefit from multiplication before it reaches the differential. This is probably the most important of all these points.
• Weight. The Veyron is a 2-ton car. Mine will be a little more. The Veyron has a carbon fiber body, with some aluminum thrown in for garnish. Mine … steel, and lots and lots of lead.
• Handling. While the center/rear weight distribution of the truck should provide the ability to drift (which would be pretty surreal in a pickup truck), handling will most certainly feel like a garage-built vehicle, not one designed by the world’s top automotive engineers.
• Aero drag. I’m building a pickup truck. Nuff said.
• Top speed. Well, no I was wrong; this is the most important point. By not having a transmission, I’m limited to the RPM range of the motor, which means that with race gearing installed in the rear end, I’ll be limited to around 110mph or so.

Still, there’s something compelling about torque — it’s the force that pushes your car off the line, and also the force that cracks axles and strips gear teeth. Truly it’s more of a curse than a bragging point in electric motorsport, since the enormous torque we have to deal with means parts must be much stronger (i.e. heavier) than for a gas-powered car of similar power. But there’s a silver lining; the ability to achieve that torque straight from zero RPM, and maintain that peak torque flat out to your battery current limit and/or motor voltage limit, means that e.g. a 400HP electric will be more than a match for a 400HP gas-powered car.

On many vehicles it’s the most difficult component to get to, and such is the case with the Hombre as well. Among those folks doing an EV conversion and replacing the heater core with an electric element, it’s a frequently-heard expression that most auto manufacurers start with a heater core hanging in space, and construct the car around it. In most cars the heater core is buried so deep in the dash, it’s a major endeavor to get to it, with multiple assemblies and sections of under-dash infrastructure requiring removal.

Some people go the easier route, forgoing the disassembly of the dash and installing an electric liquid heater in the engine bay, to warm the water in the heater core (in the place of the former gas engine). This approach doesn’t work nearly as well, but the simpler installation is tempting. As for me, I’ll be doing it the hard way, replacing the heater core with a PTC ceramic heater element, like the kind you find in inexpensive space heaters. Unlike simple glowing-wire resistive heaters, ceramic heaters generate lots of heat without the concentrated high temperature of an incandescent wire. This makes them less likely to start fires. Doing this installation will require not only replacing the heater core, but custom-fabricating its replacement. The effort will be worth it however, as unlike the heated water approach (and indeed unlike the heater in a gasoline-powered car), the electric heater will provide nearly instantaneous heat, seconds after it’s turned on.

The way this is usually done is to start with the absolute minimal ceramic space heater, which can be had for between $15 and $20 depending on where and when you look. I bought one at Target a couple weeks ago for $17. These heaters are sold under a multitude of brand names, with slight variations in the shape and color of the case, but they’re all a simple, cheap assembly involving a ceramic element in front of a fan in a cube-shaped plastic box. No oscillation or digital temparature control, no fancy curved shapes. I’ve seen these simple cube heaters sold for $35-40, but if you’re paying any more than $20 you’re being ripped off. Open the box, pull out the element, and string as many in series as necessary for your pack voltage. In my case, I’ll probably be using 3 of them. I’ve got two more of the Holmes heater pictured in the link coming from an eBay seller, for $11 each.

I tinkered again today with removing various bits from my dash before pausing to read the instructions in the shop manual. Especially the part where they say to remove the passenger side fender and then jack up the truck and remove the wheel. And then I decided, it’s December 24, I’ve got better things to do today.

Further proof that the real problem with electric vehicle battery tech is simply a matter of scale.

It’s widely understood that for high-performance RC vehicles, on the ground and in seriously demanding applications like aerobatics, the only real powerplant option is a fuel-burning engine, whether one that burns glow-fuel (”nitro”) or gasoline. This has been in great part for the same reason that gasoline is popular with full-size vehicles — energy density. Though significant energy is wasted when burning fuel for mechanical power, the enormous useable energy that can be stored in a given mass of fuel has always been so significantly greater than the energy capacity of batteries that electric RC vehicles haven’t stood a chance in direct competition. Well, now that’s changing. Lithium polymer, the same cell chemistry that powers your cell phone, is changing the game for electric power in the RC hobby, and it’s only a matter of production scale that keeps the price of larger battery packs prohibitive for larger applications.

Take another look at the page linked above. Notice the link for Kokam LiPo batteries on the sidebar? Now take a look at Pro-EV’s Electric Imp, a converted Subaru Impreza using larger cells from the same manufacturer to power dual Siemens 3-phase AC drives — one for each end of the car. The result is an electric AWD autocross car that’s silently winning trophies.

Outrageously expensive? You bet. But it’s just a matter of time before Lithium Polymer, and the still advancing state of the older Lithium Ion chemistries (powering your notebook computer, and soon your cordless power tools) become affordable in larger sizes and quantities. And maybe then we’ll see the story forshadowed by the changes seen today in electric RC vehicles, unfolding on streets in the real world.

Started digging into the dash last weekend, and while I don’t have any shots of that yet, I *do* have new shots of nearly everything from the past few weeks leading up to it, in the disassembly gallery. Along the way we’ve noticed some signs that the engine might not be the one that came with the truck, and found additional evidence under the floor covering that the truck may have been flooded at one point. More stuff I’d be pretty ticked about, if I weren’t converting the truck. For my purposes, it’s sufficient that the frame is solid and there is no body rust.

Wow, who’d have thought — some folks are actually irritated that I haven’t updated in a while. I’ll interpret that as good news, that I’m not just typing this for myself; maybe I’ll now feel more pressure to update it more often, which can only be a good thing. While not going into too much detail, there has been a lot going on for me in recent months, not all of it good. My apologies for the lapse.

Fortunately, it hasn’t been for lack of events with the project. Despite my earlier hopes, these days I still have almost no time to work on the project during the week, but I’ve set aside every Saturday afternoon from 2 to 4, and so at least every week sees some work done. Currently, the only thing left on the truck to be disassembled is the dash, to replace the heater core with a ceramic PTC element (e.g. from a $20 Wal-Mart space heater). Everything besides that is stripped down; the interior is even stripped to the sheet metal. The engine is out, the fuel and exhaust components are out, and this past weekend I built a size-accurate mockup of the motor to help with figuring out how I’m going to mount it. Pictures of all of this are forthcoming; I’ll add to this post or follow it up when I’ve got them on the server.

I can’t finish without some pics however — these taken by the folks at Netgain of a motor nearly identical to mine, produced for another customer. This shot shows the motor next to the Impulse 8, which looks like a golf cart motor in comparison. Another shows the six terminals, to allow series/parallel switching of the split field. The wire coil is from the overtemp switch, which can be used to tell the controller that the motor is overheating. This picture shows the drive end fitted with a yoke for a 1350 U-joint. I’ve been told that the customer intends to weld this yoke in place and use a telescoping driveshaft from a 4×4 to deal with suspension travel. I have different plans.

And that brings me to my favorite pictures, of the custom-machined 8620 chrome-moly shaft from the awesome folks at Dutchman Motorsports. Like the motor it’s designed for, this thing is a beast — that’s a sixteen-inch ruler there folks. The real challenge in making a part like this is the hardening process. When you heat-treat steel to harden it, you find that afterward, it’s changed shape slightly. So the manufacturing process ends up having 3 phases — milling to spec, hardening, and then milling again. Except that the second time, you can’t really mill it with cutters anymore; you’d ruin your tools. So you have to grind it. Really challenging work, unless you’re an expert like the Dutchman. The dimensional tolerance on nearly all the dimensions of this part was 2 thousandths of an inch. The finished part is accurate to within 1 thousandth.

If the Warp13 is truly “Torque City” as reportedly exclaimed by an impressed Warfield engineer, this shaft will provide a nice 6-lane highway out of it.

In case you’re curious, the other shaft in the pictures is one that another customer had made for a smaller (but still huge) Warp11 motor; apparently he arrived at the same conclusion I did and went for a custom job. His shaft was made by Mark Williams — some pretty esteemed company for mine to have in these photos.