Gearboxes and Clutches?

With an EV conversion you can go with various configurations. One is whether to go with a gearbox or just leave it out. If you go without then a drive shaft to fit will need to be sourced or made. This will be direct coupled to the motor, Netgain motors have a motor for the job designed with extra bearing and coupling etc. However the motor would need to be a bit bigger as it has to cope with the full range of revs (this is a simplified explanation, you can get more detail in the forums). The diff would also need to be changed to give a ratio to suit the motor. With a gearbox the diff doesn’t need to be changed as this has the correct ratios in conjunction with the diff. Only two gears would be used …….. say 2^nd for 0-70 km/hr and 3^rd or 4^th above that. I’ll find out which gears are best when the vehicle is operational. What I’ll do is check performance against battery amperage used and find what is the most economical and which gives me the ooh factor!

The other configuration option is to clutch or not to clutch. Obviously a clutch will make it easy to change gears but mating the motor to the gearbox needs to be precise. A measurement from the combustion motor in relation to the clutch needs to be accurately made. An adapter plate needs to be made between the gearbox and electric motor.

Or … you can leave the clutch out. Changing the gears will be a lot slower as you have to make sure that the power is taken off the motor to allow it to run down a bit then allow the syncro to mesh. This is what I will be doing as the gearboxes had no clutch when I bought them. I’ll go in to this more when I come to manufacture the adapter plate.

So, I bought two gearboxes for $350. If you look at the photo there is not an oil leak from the left gearbox, my dog decided that he would try to claim the g/box as his own and lifted his leg on it. Hence the mark on the floor ... must have given it an extra squirt. I don’t know how good they are but I’m hoping I’ll get one good one out of the two. One has a short shift throw, not that I need it as I won’t be racing! I’ve found that I don’t have a cross member that couples under the gearbox so I’ll have to source one. I did pick up a drive shaft from a Mazda wrecker for $100. So my setup will be with standard gearbox and drive shaft but no clutch.

I had contacted the president of Seven of Clubs Mazda Club of Queensland, a few weeks ago and asked if any members who had an RX like mine and if I could have a look and take photos. You see, I wasn’t there when the car was stripped down so I have boxes of stuff and I’m not sure where it all goes, some things I have multiple parts that I don’t need. Well the president said he had a 1979 RX7 (series one, mine is a 1980 … same series) and we organized to have a look and photo session. Wow, nice ride! This RX is a nice example and I got many photos but talking to him about the restoration was priceless. Having a person go through a restoration I got so many tips I wish I had it on tape. Anyway I now have a good idea of the order of priorities to see this project through. I have an order for a Netgain Warp 9 motor with ZEVA, they said it is on the next shipment which will arrive in about a month. Once I get it we will proceed in this order: adapter plate, motor mounts, battery boxes, strip out again, paint car, re-install motor and boxes and all fittings, make up panel for controller and charger. That's as far as I've planned.