Bosch Performance Line CX gen 4 modding

[Bush mechanic]

I've come across a few threads regarding modifying (or more precisely, being unable to modify!) the very popular Bosch CX performance line motors, and I am wondering if anyone out there has any more recent and more successful data to share. The consensus seems to be that Bosch is un-hackable.

I've managed to get a brilliant deal on a used Focus Thron2 which has the Performance line gen 4 system, and while it is obviously great in its own way I'd love to squeeze a bit more out of it. Lets pretend we've already had the conversations about warranties, speed limits, safety, and increased wear and tear

Has anyone successfully added an external throttle to one of these? Are there any mods that will increase total power output?

Thanks as always!

 

[Bengy22]

I came across this video a while ago, I don't own a bosch motor so I can't really say much though.

 

[Bush mechanic]

Great find, that looks just about perfect!! I'm surprised the controller doesn't pick this up but I suppose that is the beauty of a shunt mod.

Only thing now is a thumb throttle. I wonder if the signal from the BB torque sensor could simply be replaced by another hall effect throttle?

 

[marka-ee]

At first I thought it's a fake video, because his soldering iron was so huge! My question: Does Bosch Gen4 care if I wire an extra 36 volt pack to the Bosch pack ? I would wire it directly to the cells, so only the BMS could notice the extra capacity, possibly causing an error. On thumb throttle: I can see doing it by falsifying the torque sensing, but would it cause the pedals to spin 'wildly' in a dangourous way if you hit it too hard?

 

[Bush mechanic]

Regarding battery, I have never disassembled a Bosch battery so I can't really comment on how they are to work with, but I have read that Bosch have tried very hard to prevent modifications. I'd be quite cautious of touching the BMS or any internals of the battery if it is working as it should. Personally, if I had to add more capacity, I would probably try to connect another 36v pack of some description in parallel after the battery (ie splice in a parallel connection into the +/- wires between battery and controller). As normal when paralleling batteries you would just want to ensure that the characteristics and present state of charge of the two batteries you are connecting in this way are very close to prevent surges or power in or out.

Throttle - the question is going to be how to emulate the torque signal. I have not yet had research this but will look into it shorty.

Pedal spin, I think this is not an issue, the cranks or front sproket have their own freewheel, meaning the motor can spin the front chainring but the pedals can remain stationary.