openinverter forum

Finally got a github repo setup for my ZF 8HP controller project. Primary goal is to control the valve block in the GA8P75HZ gearbox for EV conversions. Should work also with traditional ICE 8HP setups.

https://github.com/damienmaguire/8HP-TCU/tree/main

I did intend to use my '97 E39 as the test vehicle for this project but might use my 2008 E92 instead. Will see ...

do you have any progress?

Little busy

Hi Dear Jack
Thanks for your interesting project.
I have some expertise in electronics and I want to use your project for my swap
You said that this board can be used on internal combustion engines as well, but it does not have tps or map inputs. Also, it has not outputs for shift up & down and also speed input. And if you can give me some guidance on its firmware, you have solved all my problems.
thank you very much.

Friends, good day. I'd like to talk about your controller and use it on an AA80E automatic transmission. I'm ready for testing, soldering, and assembly.

Please forgive me for being new, and my English is struggling. It hurts your eyes when you read it.

I'd appreciate any insightful suggestions.

Thank you very much.

The get repo only has the kicad files for the adapter and not the tcu pcb, does anyone have these or know where I could find them, if Jack/Damien could add them to the repo that would be ideal. I hope this finds it way to Jack so i can say thanks for all your hard work and dedication to the community

Back at this after a while. Sorry for the absence folks. Life and other things. Anyway, finally got my hands on the matching inverter at a reasonable price with the bonus of having the plugs still attached. This inverter will get an OI board. Also has a dcdc built in.

Re the TCU I am in the midst of a redesign as the first version did not have closed loop current control of the solenoids which is a requirement. Currently looking at the MAX22200 IC for this purpose.

Also did a 3d scan of the bellhousing and cut out a basic adapter plate.

I think, but don't know, that this is or is highly related to, the transmission used in the Jeep Wrangler 4xe here in the States. Having an OI solution for it would be awesome.

I haven't done much digging, but I understand there are some aftermarket controllers out there for the regular 8HP. I wonder if that might be the solution for the transmission side, and then pair that with your inverter work? I've seen some Youtube videos from Nivlac57 about using the 8HP in his drag cars. I'll have to dig through them to find the TCUs he's tried after work today.

Messy work bench today

Most of the interest so far seems to be from new usernames looking to control this transmission in ice powered vehicles.

For people interested in the electric side of this but silent and or confused, here's some info to help understand the significance of this transmission / hybrid transmission.

200kw (250hp) is what some of the hybrid variant electric motors are rated to but couple that with 8 speeds. For reference, the gs450h is rated to 147kw and has 2 speeds.
The 8hp was designed with fuel economy in mind, lots about down speeding the ice but likely also means they looked at lower drag components / design too (read as efficiency for us). It was also designed to target dual clutch transmission shift speed of .2 seconds, it's not a slushbox.

There's a very large list of vehicles which use this transmission, a ton of availability in RWD and AWD variants across lots of power ranges.
https://en.wikipedia.org/wiki/ZF_8HP_transmission
This specific reverse engineering is targeting the bmw hybrid transmission but the controls will likely cross over to other variants as well. No promises but likely in zf packaging this for so many different vehicles.

Taking on projects like this is a ton of effort. If you're interested in this transmission / hybrid transmission run in electric mode, please throw a like ( ) to Damien's original post to show interest if you haven't.

While likes help understand interest level, contributions help immensely to make these projects actually happen. Please consider supporting Damien on Patreon if you can. https://www.patreon.com/evbmw
If everyone interested contributed even a small amount it would go a long way towards helping make this happen.

I and others will help how we can to make this happen as well.

Please show your support how you can.

I had a gap in work today and decided to do some digging to hopefully be helpful on this project.

First, it does appear from what I can find that this is essentially the same transmission used in the Jeep Wrangle 4xe PHEV and the Grand Cherokee 4xe PHEV (not the e-torque mild hybrid of either). For Jeep/Stellantis the transmission code is 8P75HP.

Second, from the non-electrified 8HP side, which I assume might be helpful:
From this Nivlac57 video, the TCU is in the transmission, and is controlled over CAN. There are CAN emulation options, but obviously those are limited to the stock mapping. There is an expensive bypass option from TurboLamik. Most interesting for our purposes: There is an aftermarket controller that uses a different firmware that allows more control, from MaxxECU. Their technical documentation is here. Not sure if its at all helpful, but figured I'd share. I haven't dug through it all yet. They do have a Youtube video on flashing the TCU, and it looks like these use a Chinese tool for reflashing the stock TCU. I think this is that tool. I suppose it might be possible to create a new firmware for our purposes, but that's beyond my knowledge.

Unfortunately, I traded in my Challenger (which had an 8HP ICE variant) last year, I wish I had grabbed a CAN log from that before hand. I might know someone with a 4xe Wrangler that would let me CAN log, I'll have to investigate that.

So in today's exciting episode. Got the aux 12v oil pump , valve body and tcm removed. Got to work on the pump. Naturally no info available. Discovered the following :

*Uses LIN V2 at 19200 baud
*Responds to ids 0x32 , 0x33 and 0x34
*Command id is 0x30. byte 7 is a counter from 0x00 to 0x0f.

So far I have not had the pump run but managed to trick the oem tcm into communicating with the pump via an obd adapter.

Hey,

Very cool Project!
I would Like to use the Transmission also in my Project Car.
So you want to use the zf Transmission Controller and Talk with them over can or do you Plan to develop a own Transmission Controller?

I Like the approach maxxecu and cantcu do, to use the zf Controller and give them the right can telegramms.

How can i Support the devolepment?

Sorry for my Bad english