OEM-level 8HP swaps in E-series cars

Svmp

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Dec 23, 2019
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M50 DCT & M57 DCT
Thought i'd share some info on what's possible nowadays with these transmissions.
I've been driving around for over 6 months now with my 8HP-swapped daily E91 using my own controller (CANTCU), constantly doing R&D and developing further, and now it's pretty much finished regarding E6x/7x/8x/9x integration.

This is the only existing solution that keeps the OEM TCU inside the transmission, making it possible to install without disassembling/soldering etc, doesn't need any tuning, and works silky smooth like OEM. Simply put, it makes the car and the 8HP understand each other.

At the moment there are some beta testers driving around in various cars/engines like N54/M57/N57. Here's a video example of a fast diesel (E92 330xd N57) with an 8HP70X transmission (fully stock trans in the video, it got xHP afterwards).


The nice thing about E-series xdrive-cars is that the transfer case from a manual/6HP fits directly onto a xdrive-model 8HP transmission, so it will also work directly without any extra modifications.

To keep this post more informative than just a crude advert, i want to mention that there also are other solutions available to control the 8HP, in which the OEM TCU is removed and replaced with an aftermarket unit that fully controls the transmission instead, those solutions are TurboLamik and HTG.
 

johnnyd40

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Jun 21, 2022
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looks awesome, I read somewhere that the front diff is a weak point, is this true? I would suspect the transfer cases to be a weak point
 
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Svmp

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Dec 23, 2019
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M50 DCT & M57 DCT
looks awesome, I read somewhere that the front diff is a weak point, is this true? I would suspect the transfer cases to be a weak point
Well, surely both the transfer case and front diff will at some point be weak points. But i haven't really investigated it as i don't have an xdrive-car myself.

Do you include a adapter plate?
Nope, we concentrate on controlling things. There are a ton of vendors supplying mechanical adapter plates etc for conversions like these. Places like PMC Motorsport, DomiWorks etc. Also, an adapter isn't even needed if you use a 8HP45 from a N55.
 
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MR-KRAKA

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May 23, 2020
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I was trying to hold off on making a post on this until after I got to the track but... I’ve been running the CANTCU for about a month now E90/N54/xDrive 8HP45X (first ever?) I am impressed with how far the software has come in just the short time and how fast Ken was able to implement various fixes (and improvements) throughout the Beta. There was plenty of bugs to work out in the beginning mostly Gas vs Diesel issues and I know I was the Bane of Ken’s existence for a while but it all paid off in the end. The Software is very polished now and he’s still pumping out the updates. While I am still working on the DME tune (IJE0S xDrive life) side of things as time allows, I can say this implementation is as close to oem as you’re going to get for this type of swap. By far best “mod” I’ve done so far besides upgraded turbos. Second gear gets placed in a very nice ratio between the 6hp’s 1st/2nd for launch and just DD duties in general. There is also maybe a little placebo effect going on banging through all the gears so quickly when you’re used to the long 6HP. It definitely livens things up a little more.

I opted to try this unit over the others for a few reasons. First I couldn’t find one example of the other options out there having functional xDrive outside of a reply to a YouTube comment saying it would be possible. Secondly you are using the oem TCU in this case programmed by ZF and combining that with XHP which I feel has proven to be quite reliable over the years. There has been far more testing than all the others out there with this combo. Direct control of solenoids/full standalone I’m sure has its advantages over this at racecar level but for me I wanted to be able to hand the keys to my wife without worries or her telling me somethings not right. Another factor was the language barrier vs the others. While Ken is based out of Finland he spoke perfect English and was not an issue at all even with al the technical speak. Time difference was the only thing that got in the way sometimes but I’m not sure if the guy sleeps anyways? None of that should matter now since the unit is plug and play past initial setup, this was all during testing.

For the physical swap itself the only modification required is adapting of the smaller 6HP oil cooler lines to the larger ports of the 8HP45. There’s several offerings out there like th adapter plates take your pick. And for the exhaust mount to the transfer case I had to find just the right length bolt/bushing washer/combo to make the stock bracket work because the pan seems to sit a little further back than the 6hp. Otherwise a direct swap. This applies when converting from 6HP19/21 to 8HP45X from an N55 powered F10 in my case. 8HP70 will require an adapter plate setup and I may regret not taking that path once I really start pushing it but time will tell. So far holding up ok in the 550-600whp range for me. I was concerned about the additional length with xDrive being uncharted territory. I didn’t have one to compare but if it were to add even a few mm To the overall package I suspect I would be needing a custom driveshaft at the very least. The 8HP45 is largely the same trans used on the B58 powered stuff now and they seem to be doing ok at least up to my power goals currently. These trans are cheap and readily available if you shop around but I definitely do not want to have to do this swap again anytime soon at least without a lift…

Next up I will hopefully get back to the drag strip soon, maybe tomorrow to see what kind of net ET gain there is at the same power level as last year. I suspect it should be significant from my 60ft alone. Here’s just a short video I made for internet proofz please don’t make fun of my skills lol

I’d be happy to answer any questions on the swap. This is not a paid promotion, no one put me up to this. Just a happy PITA customer 😁
 
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sultan.of.swing

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Jul 19, 2022
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New guy here and I think I came to the right place. I have a 2008 335xi and from what I am gathering based on my reading here as far as hardware needed.
F10 535xi lets say 2013 with the N55 and the 8hp45X
Torque converter from the same vehicle.
If I am reading this correctly the 8HP45X is a 100% complete bolt in and the transfer case from my 6at will bolt directly up to the 8HP45 and all my current driveshafts will bolt right up?
I am aware of turbo lamik and HTG but I am just looking at the physical hardware side of things right now.
 

MR-KRAKA

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May 23, 2020
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New guy here and I think I came to the right place. I have a 2008 335xi and from what I am gathering based on my reading here as far as hardware needed.
F10 535xi lets say 2013 with the N55 and the 8hp45X
Torque converter from the same vehicle.
If I am reading this correctly the 8HP45X is a 100% complete bolt in and the transfer case from my 6at will bolt directly up to the 8HP45 and all my current driveshafts will bolt right up?
I am aware of turbo lamik and HTG but I am just looking at the physical hardware side of things right now.
The trans cooler lines need to be adapted but there are several options available for that already. The 8HP ports are larger but uses the same style connection. You also need to swap out the cable shifter for an E-shift style. That was all for me hardware wise. I am E90 LCI so there may be some unforeseen small differences. IIRC pre-Lci/Lci have different rears/offsets. Best bet would be to compare part numbers between drive shafts to be sure…

I was able to get to the drag strip a couple weeks ago. Track prep was non existent so my 60ft really suffered doing 1.9’s all night either babying it or blowing the tires off leaving around 5psi. I think 10’s will be possible once I get to my normal strip if I can pull off 1.6’s. Car is much more consistent now as far as shifts go it didn’t miss a beat. Not bad for a junkyard swap with 125k on it and only a filter/fluid flush. Car should be in the 550-600whp range based on trap/weight and still fairly conservative on the tune. I made a little video of the difference between launching both ways. I still have it very biased to the rear with xDelete to protect my front end parts but may need to bring some back to hit my goals.

 
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MR-KRAKA

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May 23, 2020
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This only is a direct bolt up for the x drive guys?
No same for rwd. F series N55 donor if going with a 8HP45. 8HP70 needs an adapter but will hold much more power. The 45 is serving me well for now but I wish I had that cushion I would have with the 70. You can look to the B58 guys for the limits of the 45. The 8HP50 that they use is mostly unchanged from the 45 internally.
 

doublespaces

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Oct 18, 2016
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Is there a drive shaft length difference? Photos would be nice here.

Also, hasn't this can translator box idea been around for quite some time? Pretty sure they do the same thing with the 6L80 swaps.

tcm-2600.jpg


 
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MR-KRAKA

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May 23, 2020
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Is there a drive shaft length difference? Photos would be nice here.

Also, hasn't this can translator box idea been around for quite some time? Pretty sure they do the same thing with the 6L80 swaps.

View attachment 71861

Overall package length of the trans/transfer case was identical to stock for me. I can’t speak for pre-LCI but I doubt there is any difference in driveshafts. The only other little thing I remember is that you will have to get creative with the nut bolt combo for the exhaust bracket that mounts to the transfer case because the pan/filter sits a little further back than the 6HP and really limits space there. If you let me know what you want a photo of I can get it but everything there really isn’t much to see it looks factory.

For sure the concept is nothing new. But there is nothing else out there the talks to our DME this way besides the other two standalone units. No CEL’s or Christmas tree on dash for me. Everything works as it should.
 

doublespaces

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Overall package length of the trans/transfer case was identical to stock for me. I can’t speak for pre-LCI but I doubt there is any difference in driveshafts. The only other little thing I remember is that you will have to get creative with the nut bolt combo for the exhaust bracket that mounts to the transfer case because the pan/filter sits a little further back than the 6HP and really limits space there. If you let me know what you want a photo of I can get it but everything there really isn’t much to see it looks factory.

For sure the concept is nothing new. But there is nothing else out there the talks to our DME this way besides the other two standalone units. No CEL’s or Christmas tree on dash for me. Everything works as it should.

What about xhp flash?
 

MR-KRAKA

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May 23, 2020
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What about xhp flash?
Same procedure for loading xhp into any other car. If you have an existing xhp tune however that will not be transferring. You will need an all new account using the vin from the donor trans. Part of the install is wiring up its own dedicated obd port for coding/flashing the trans side. I keep it tucked away below the shifter cover. You will also need to clear/reset the security on the donor trans (ISN) There are a few methods for this and I believe they offer the service for free if you are local or willing to ship the tcu to them. IIRC he was working on a way to do this remotely. Maybe Ken can chime in on it. I haven’t had a need to bug him in a while 😃
 
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JLFC

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Mar 28, 2022
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11’ Space Grey BMW E90 335i
This is tremendously exciting guys! What an amazing community.

Hoping an easy OEM-like 8HP swap becomes a reality soon for us slushbox owners.

I'd do it in a heartbeat!! 🤩
 
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Jern54

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Oct 18, 2019
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I've received my CAN TCU to perform a F8X DCT swap into my N54 E91.

So far the support is outstanding. Kenneth is a very knowledgeable guy.
 
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Svmp

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Dec 23, 2019
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It's very nice to see some discussion starting here! We've got a lot of 8HP-swaps especially in the E6/7/8/9x cars now, and people are loving it. :hearteyes:

I've received my CAN TCU to perform a F8X DCT swap into my N54 E91.

So far the support is outstanding. Kenneth is a very knowledgeable guy.
Thanks for the kind words, can't wait for you to get it running! :sunglasses:

Same procedure for loading xhp into any other car. If you have an existing xhp tune however that will not be transferring. You will need an all new account using the vin from the donor trans. Part of the install is wiring up its own dedicated obd port for coding/flashing the trans side. I keep it tucked away below the shifter cover. You will also need to clear/reset the security on the donor trans (ISN) There are a few methods for this and I believe they offer the service for free if you are local or willing to ship the tcu to them. IIRC he was working on a way to do this remotely. Maybe Ken can chime in on it. I haven’t had a need to bug him in a while 😃

Thanks for sharing information in the topic, i appreciate it! It sounds like everything is working nicely, i was a bit worried already with no feedback for awhile. :tonguewink:

Regarding the ISN reset, if i have some spare time in the winter, i will make a built-in flasher in CANTCU. For now we offer the reset for free for all our customers, but it involves shipping the OEM TCU to us (Europe) so it's usually not beneficial for customers far away.