In a little over a week, I will be going home for my spring break. During those 10 or so days that I am home, I have a number of things on my checklist that I want to try to accomplish.
My main one is to re-engineer the transfer case. The transfer case is a sideways open differential, so it relies on the resistance of both the back and front wheels to send torque where it is needed. Right now, my solution of using steel to hold the front output still will likely not hold up. The method I have seen in a few cases on the BMW forums, is to open the transfer case and weld the front output gear set to prevent it from turning, thus forcing all of the power to the rear.
I know this is risky, and not the best solution. It could break the transmission and the transfer case is still likely going to reduce the power to the rear wheels by a bit, so there is lost efficiency there. My other option is getting a RWD transmission, but I am not sure on how the mounting for that would go. I have worked with these style cars in the past, and there’s a very good chance that the mounting methods for both transmissions will be ever so slightly different that it doesn’t fit right. Not to mention, the whole drive shaft assembly would need to be changed too. It’s a large expense, but I am not ruling it out. I have a source for those parts, just in case something does go wrong with the welding option.
Next, I’d like to try to get the motor coupled with the transmission in some sense, whether that’s mounting them together and/or getting the input/output shafts to connect. I think the mounting will be a bit more daunting, so I might leave that one for another time.
Lastly, I just found out that the controller I tracked down has just completed its refurbishment process, and now I am attempting to get the funds together to purchase it. It’s a reasonable price, $550 for a 144v 1000 amp DC controller. I am just paying for the parts that had to be replaced, so it’s miles cheaper than buying the next cheapest option. Anything else with these specs is likely going to be way over the $2,000 mark, so I don’t want to miss out on this deal.
A reader reached out to me regarding a Zivan NG3 charger intended for 144v lithium batteries, so if I can get some money together to ship it, it’ll be a great piece to have once I finally find a source for some lithium modules.
All in all, there’s still plenty to be done. And honestly, there isn’t really that much work that needs to happen on the car, it’s more about the work being done to build up the necessary funding to obtain these parts. The timing has been kind of a blessing though, as it has made me realize a number of faults in my original design and refine them into a much better final product.
It certainly won’t be perfect, but it will get closer by the day.