zf6hp19 to zf8hp45 swap

1spool

New Member
Dec 31, 2018
8
Hi everyone and Happy New Year!
I drive a single turbo (6266) e92 335xi fitted with the infamously sluggish zf6hp19 6-speed auto that can't hold power, and it's slipping with only 18psi. Instead of doing a rebuild or swapping to a manual (it's my daily and I live in busy NYC) I thought of doing a zf8hp45 swap from an e84 x1.
I can't confirm this, but it seems that the e90 and the e84 are essentially the same chassis, the e84 just having an suv body sitting on it. I came across a thread where this swap was discussed in Australia in early 2018 but they never followed up in regards to whether it worked or not.
This swap would be a great solution as the zf6 is rated to hold 295ftlb but people report them starting to slip only around 450ftlb, so applying the same 50% increase to the zf8hp45's claimed limit of 450ftlb (ZF's claim) would mean that in practice it can hold up to approx. 675ftlb.

Here is what a week's worth of research revealed:
- zf6hp19 and zf8hp45's bell housing are identical
- e92 & e84 driveshafts (front and rear) are identical, same part #
- e92 & e84 torque converters are identical, same part #
- e92 & e84 CAN control unit is identical, same part #
- e92 & e84 TCUs are identical, same part #
- Zf8's are VIN locked, which may present an issue. A tuning company I spoke to said it should not be too difficult to get around that


I spoke to xHP about this project and they said that since the zf8 is VIN locked, it communicates with the FEM and the DME before starting to operate, saying this swap would require a different CANBUS architecture.

I would love to get your insight on this project, I am pretty set on making this happen but my knowledge of electrical vehicular communications and how that sort of stuff works is very limited. I'll be posting this thread on the other forums as well. All feedback would be really appreciated.
smile.gif


**Please don't suggest a manual swap; it makes no sense to manual swap a car that is rolled off the assembly line with a manual...**
 

doublespaces

Administrator
Oct 18, 2016
6,959
AZ
Before you go too far, you should check that info because you should have the ZF 6HP19TU, ZF 6HP19Z, ZF 6HP21. All of which are the same transmission, the name varies depending on which catalog you are looking at.

The ZF 6HP21 is a 21mm input shaft and is a second generation transmission as is the 6HP28 found in the diesel. The 6HP19 is a first generation transmission alongside the 6HP26 which is the one Nizpro is known for upgrading.

Regarding the swap, you're in for some interesting work because those transmissions are installed in BMW vehicles which use the FlexRays powertrain communication system, so an interpreter box would be required. You want to speak to @Bimaxtremeretro as they can do this, they just need someone's car and money, in Australia.
 

1spool

New Member
Dec 31, 2018
8
Thanks for your reply-- I have seen the thread here before with @Bimaxtremeretro and sent him a message, I'm still awaiting his response. NYC is very far from Australia, unfortunately, but maybe he can shed some light on the situation.
 

jelias17

New Member
Aug 10, 2017
6
My 6hp is starting to slip I live in Florida and am looking into getting involved with this swap, I have my own shop and Have the time to do something like this. Keep us updated, you have a guinea pig in south florida now.

Thanks for your reply-- I have seen the thread here before with @Bimaxtremeretro and sent him a message, I'm still awaiting his response. NYC is very far from Australia, unfortunately, but maybe he can shed some light on the situation.
 

1spool

New Member
Dec 31, 2018
8
Good to know I’m not the only one driven to do this! I got my zf8 this morning, but I’m still at a dead end in regards to tuning. I reached out to half a dozen trans coding/tuning shops/services to no avail. No one has done this before and seems that no one wants to get into it. If you come across someone with some more info on this let me know, I’ll be happy to share more info I’ve gathered.
 

jelias17

New Member
Aug 10, 2017
6
Good to know I’m not the only one driven to do this! I got my zf8 this morning, but I’m still at a dead end in regards to tuning. I reached out to half a dozen trans coding/tuning shops/services to no avail. No one has done this before and seems that no one wants to get into it. If you come across someone with some more info on this let me know, I’ll be happy to share more info I’ve gathered.
I was wondering if @Bimaxtremeretro was willing to do remote work and even remote troubleshooting in order to get this done in the U.S. As some sort of remote experiment where they guide us and we do the experiment here.
 

1spool

New Member
Dec 31, 2018
8
Thanks, I’ll reach out to them. In regards to the TCU- the e90 tcu & e84 tcu are identical, same part number which might be helpful.
 

1spool

New Member
Dec 31, 2018
8
Turbo Lamik from Poland did this swap on a e92 335, you can find them on Facebook & youtube. I contacted them and they said they swapped in a zf8hp70, the beefiest zf8, by using an adapter plate for the bell housing and a custom tcu. Very cool stuff.
 
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