Complex math

So, having chatted to various people we were referred to the lovely folks at BGH Geartech, who build Type 9 Ford gearboxes for race / road / rally. Now whilst we’d love to upgrade the motor, common sense (and financial imperatives) mean that we’re probably sticking with the NetGain 8″ DC motor that we’ve got. A more modern AC motor would be more efficient and in many respects probably a better plan, but unless we suddenly come into bucket loads of money, that Netgain will be it.

So, we handed off the specs for the motor and back axle that we’ve got to BGH, and away they went. Then they came back. The problem is the torque graph stops at 100 rpm. And the motor doesn’t start at 100 rpm, it starts at 0. And electric motors produce pretty much all of their torque from 0 rpm up. The Morris Ital-variant-A-Series-engine that currently sits in the Minor produces around 70lb/ft at around 3000 rpm, but as anyone who’s ever driven any manual gearbox’d car will know, it produces virtually no torque at 1rpm. Trying to pull away when you’re learning to drive gives you a rapid understanding of torque and how little a petrol engine produces at low revs.

So, building a box that can even hope to tolerate the kind kind of power a large electric motor produces, 152lb/ft; more than double the existing torque… And a motor that will supply that from a stationary – the point at which the most stress is on the transmission? That’s a challenge. And to do so without exactly knowing the specs for the motor is more tricky. So for the minute, we’ve left the problem with them, but it’s going to need a fairly rapid solution, because the car has gone up to our Morris specialist for installation of the brakes, axle, and box.

We’d hoped to go straight, at this point, into the electric conversion. But we’re planning to move to the ‘states in about 8 weeks (if the visa application is successful), and the only car we’re planning on taking is the Minor. So, an A-Series engine will be going back in, albeit mated to the box intended in the long run for the EV conversion (another factor complicating the gearbox build) until we can gather the funds for the rest of the conversion.

Still, it’s nice to have some progress.

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